Publications by authors named "Vincent W Yang"

140 Publications

Selective killing of cancer cells harboring mutant RAS by concomitant inhibition of NADPH oxidase and glutathione biosynthesis.

Cell Death Dis 2021 Feb 16;12(2):189. Epub 2021 Feb 16.

Division of Gastroenterology and Hepatology, Department of Medicine, Stony Brook University, Stony Brook, NY, USA.

Oncogenic RAS is a critical driver for the initiation and progression of several types of cancers. However, effective therapeutic strategies by targeting RAS, in particular RAS and RAS, and associated downstream pathways have been so far unsuccessful. Treatment of oncogenic RAS-ravaged cancer patients remains a currently unmet clinical need. Consistent with a major role in cancer metabolism, oncogenic RAS activation elevates both reactive oxygen species (ROS)-generating NADPH oxidase (NOX) activity and ROS-scavenging glutathione biosynthesis. At a certain threshold, the heightened oxidative stress and antioxidant capability achieve a higher level of redox balance, on which cancer cells depend to gain a selective advantage on survival and proliferation. However, this prominent metabolic feature may irrevocably render cancer cells vulnerable to concurrent inhibition of both NOX activity and glutathione biosynthesis, which may be exploited as a novel therapeutic strategy. In this report, we test this hypothesis by treating the HRAS-transformed ovarian epithelial cells, mutant KRAS-harboring pancreatic and colon cancer cells of mouse and human origins, as well as cancer xenografts, with diphenyleneiodonium (DPI) and buthionine sulfoximine (BSO) combination, which inhibit NOX activity and glutathione biosynthesis, respectively. Our results demonstrate that concomitant targeting of NOX and glutathione biosynthesis induces a highly potent lethality to cancer cells harboring oncogenic RAS. Therefore, our studies provide a novel strategy against RAS-bearing cancers that warrants further mechanistic and translational investigation.
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http://dx.doi.org/10.1038/s41419-021-03473-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7887267PMC
February 2021

KLF5 Is Induced by FOXO1 and Causes Oxidative Stress and Diabetic Cardiomyopathy.

Circ Res 2021 Feb 2;128(3):335-357. Epub 2020 Dec 2.

Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA (I.D.K., M.H., A.M.L., E.M., D.P., W.J.K., K.D.).

Rationale: Diabetic cardiomyopathy (DbCM) is a major complication in type-1 diabetes, accompanied by altered cardiac energetics, impaired mitochondrial function, and oxidative stress. Previous studies indicate that type-1 diabetes is associated with increased cardiac expression of KLF5 (Krüppel-like factor-5) and PPARα (peroxisome proliferator-activated receptor) that regulate cardiac lipid metabolism.

Objective: In this study, we investigated the involvement of KLF5 in DbCM and its transcriptional regulation.

Methods And Results: KLF5 mRNA levels were assessed in isolated cardiomyocytes from cardiovascular patients with diabetes and were higher compared with nondiabetic individuals. Analyses in human cells and diabetic mice with cardiomyocyte-specific FOXO1 (Forkhead box protein O1) deletion showed that FOXO1 bound directly on the promoter and increased KLF5 expression. Diabetic mice with cardiomyocyte-specific FOXO1 deletion had lower cardiac KLF5 expression and were protected from DbCM. Genetic, pharmacological gain and loss of KLF5 function approaches and AAV (adeno-associated virus)-mediated delivery in mice showed that KLF5 induces DbCM. Accordingly, the protective effect of cardiomyocyte FOXO1 ablation in DbCM was abolished when KLF5 expression was rescued. Similarly, constitutive cardiomyocyte-specific KLF5 overexpression caused cardiac dysfunction. KLF5 caused oxidative stress via direct binding on NADPH oxidase ()4 promoter and induction of NOX4 (NADPH oxidase 4) expression. This was accompanied by accumulation of cardiac ceramides. Pharmacological or genetic KLF5 inhibition alleviated superoxide formation, prevented ceramide accumulation, and improved cardiac function in diabetic mice.

Conclusions: Diabetes-mediated activation of cardiomyocyte FOXO1 increases KLF5 expression, which stimulates NOX4 expression, ceramide accumulation, and causes DbCM.
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http://dx.doi.org/10.1161/CIRCRESAHA.120.316738DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7870005PMC
February 2021

Aberrant differentiation of intestinal stem cells due to inflammation-induced mitochondrial dysfunction predicts postoperative recurrence of Crohn's disease.

Dig Med Res 2020 Dec 30;3. Epub 2020 Dec 30.

Department of Medicine, Renaissance School of Medicine at Stony Brook University, Stony Brook, New York, USA.

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http://dx.doi.org/10.21037/dmr-2020-15DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7806188PMC
December 2020

Cardiomyocyte Krüppel-Like Factor 5 Promotes De Novo Ceramide Biosynthesis and Contributes to Eccentric Remodeling in Ischemic Cardiomyopathy.

Circulation 2021 Mar 12;143(11):1139-1156. Epub 2021 Jan 12.

Center for Translational Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, PA (M.H., D.P., I.D.K., C.M., S.R., E.G., R.K., K.D.).

Background: We previously showed that cardiomyocyte Krϋppel-like factor (KLF) 5 regulates cardiac fatty acid oxidation. As heart failure has been associated with altered fatty acid oxidation, we investigated the role of cardiomyocyte KLF5 in lipid metabolism and pathophysiology of ischemic heart failure.

Methods: Using real-time polymerase chain reaction and Western blot, we investigated the KLF5 expression changes in a myocardial infarction (MI) mouse model and heart tissue from patients with ischemic heart failure. Using 2D echocardiography, we evaluated the effect of KLF5 inhibition after MI using pharmacological KLF5 inhibitor ML264 and mice with cardiomyocyte-specific KLF5 deletion (αMHC [α-myosin heavy chain]-KLF5). We identified the involvement of KLF5 in regulating lipid metabolism and ceramide accumulation after MI using liquid chromatography-tandem mass spectrometry, and Western blot and real-time polymerase chain reaction analysis of ceramide metabolism-related genes. We lastly evaluated the effect of cardiomyocyte-specific KLF5 overexpression (αMHC-rtTA [reverse tetracycline-controlled transactivator]-KLF5) on cardiac function and ceramide metabolism, and rescued the phenotype using myriocin to inhibit ceramide biosynthesis.

Results: KLF5 mRNA and protein levels were higher in human ischemic heart failure samples and in rodent models at 24 hours, 2 weeks, and 4 weeks post-permanent left coronary artery ligation. αMHC-KLF5 mice and mice treated with ML264 had higher ejection fraction and lower ventricular volume and heart weight after MI. Lipidomic analysis showed that αMHC-KLF5 mice with MI had lower myocardial ceramide levels compared with littermate control mice with MI, although basal ceramide content of αMHC-KLF5 mice was not different in control mice. KLF5 ablation suppressed the expression of SPTLC1 and SPTLC2 (serine palmitoyltransferase [SPT] long-chain base subunit ()1 2, respectively), which regulate de novo ceramide biosynthesis. We confirmed our previous findings that myocardial SPTLC1 and SPTLC2 levels are increased in heart failure patients. Consistently, αMHC-rtTA-KLF5 mice showed increased SPTLC1 and SPTLC2 expression, higher myocardial ceramide levels, and systolic dysfunction beginning 2 weeks after KLF5 induction. Treatment of αMHC-rtTA-KLF5 mice with myriocin that inhibits SPT, suppressed myocardial ceramide levels and alleviated systolic dysfunction.

Conclusions: KLF5 is induced during the development of ischemic heart failure in humans and mice and stimulates ceramide biosynthesis. Genetic or pharmacological inhibition of KLF5 in mice with MI prevents ceramide accumulation, alleviates eccentric remodeling, and increases ejection fraction. Thus, KLF5 emerges as a novel therapeutic target for the treatment of ischemic heart failure.
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http://dx.doi.org/10.1161/CIRCULATIONAHA.120.047420DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7965352PMC
March 2021

Interplay among p21, MUSASHI-1 and Krüppel-like factor 4 in activation of Bmi1-Cre reserve intestinal stem cells after gamma radiation-induced injury.

Sci Rep 2020 10 27;10(1):18300. Epub 2020 Oct 27.

Department of Medicine, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY, USA.

Gamma radiation is a commonly used adjuvant treatment for abdominally localized cancer. Since its therapeutic potential is limited due to gastrointestinal (GI) syndrome, elucidation of the regenerative response following radiation-induced gut injury is needed to develop a preventive treatment. Previously, we showed that Krüppel-like factor 4 (KLF4) activates certain quiescent intestinal stem cells (ISCs) marked by Bmi1-Cre to give rise to regenerating crypts following γ irradiation. In the current study, we showed that γ radiation-induced expression of p21 in Bmi1-Cre cells is likely mitigated by MUSASHI-1 (MSI1) acting as a negative regulator of p21 mRNA translation, which promotes exit of the Bmi1-Cre cells from a quiescent state. Additionally, Bmi1-specific Klf4 deletion resulted in decreased numbers of MSI1 cells in regenerating crypts compared to those of control mice. We showed that KLF4 binds to the Msi1 promoter and activates its expression in vitro. Since MSI1 has been shown to be crucial for crypt regeneration, this finding elucidates a pro-proliferative role of KLF4 during the postirradiation regenerative response. Taken together, our data suggest that the interplay among p21, MSI1 and KLF4 regulates Bmi1-Cre cell survival, exit from quiescence and regenerative potential upon γ radiation-induced injury.
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http://dx.doi.org/10.1038/s41598-020-75171-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7591575PMC
October 2020

KLF4 Regulates Goblet Cell Differentiation in BMI1 Reserve Intestinal Stem Cell Lineage during Homeostasis.

Int J Stem Cells 2020 Nov;13(3):424-431

Department of Medicine, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, USA.

Krüppel-like factor 4 (KLF4) is a zinc-finger transcription factor, expressed in villus cells of the intestinal epithelium, that promotes cellular differentiation and tissue homeostasis. Previous studies suggest that BMI1 cells represent secretory progenitors with reserve intestinal stem cell (rISC) activity. However, it has not been elucidated how KLF4 contributes to crypt regeneration originated from BMI1 rISC lineage during homeostasis. In this study, -Cre;Rosa26 (Ctrl) and -Cre;Rosa26; () mice were injected with tamoxifen to label BMI1 cells and their lineage and to delete . During homeostasis, MUC2 goblet cells appeared in the BMI1 cell lineage 2, 3 and 7 days after tamoxifen administration. After deletion in BMI1 cells, the number of KLF4 and MUC2 cells in cells decreased in mice compared with Ctrl mice. Thus, KLF4 was positively correlated with goblet cell differentiation in BMI1 cell derived lineage. In analysis, organoids derived from single cells of Ctrl mice contained MUC2-expressing cells that co-expressed KLF4. On the other hand, organoids derived from Klf4-deleted cells from mice showed reduced number of MUC2-expressing cells. In conclusion, these results suggest that KLF4 regulates goblet cell differentiation in BMI1 ISC-derived lineage during homeostasis.
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http://dx.doi.org/10.15283/ijsc20048DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7691855PMC
November 2020

Krüppel-like Factor 5 Regulates Stemness, Lineage Specification, and Regeneration of Intestinal Epithelial Stem Cells.

Cell Mol Gastroenterol Hepatol 2020 25;9(4):587-609. Epub 2019 Nov 25.

Department of Medicine, Stony Brook University Renaissance School of Medicine, Stony Brook, New York; Department of Physiology and Biophysics, Stony Brook University Renaissance School of Medicine, Stony Brook, New York. Electronic address:

Background & Aims: Self-renewal and multipotent differentiation are cardinal properties of intestinal stem cells (ISCs), mediated in part by WNT and NOTCH signaling. Although these pathways are well characterized, the molecular mechanisms that control the 'stemness' of ISCs are still not well defined. Here, we investigated the role of Krüppel-like factor 5 (KLF5) in regulating ISC functions.

Methods: We performed studies in adult Lgr5;Rosa26 (Lgr5) and Lgr5;Klf5;Rosa26 (Lgr5) mice. Mice were injected with tamoxifen to activate Cre recombinase, which deletes Klf5 from the intestinal epithelium in Lgr5 but not Lgr5 mice. In experiments involving irradiation, mice were subjected to 12 Gy total body irradiation (TBI). Tissues were collected for immunofluorescence (IF) analysis and next generation sequencing. Oganoids were derived from fluoresecence activated cell sorted- (FACS-) single cells from tamoxifen-treated Lgr5 or Lgr5 mice and examined by immunofluorescence stain.

Results: Lgr5 ISCs lacking KLF5 proliferate faster than control ISCs but fail to self-renew, resulting in a depleted ISC compartment. Transcriptome analysis revealed that Klf5-null Lgr5 cells lose ISC identity and prematurely differentiate. Following irradiation injury, which depletes Lgr5 ISCs, reserve Klf5-null progenitor cells fail to dedifferentiate and regenerate the epithelium. Absence of KLF5 inactivates numerous selected enhancer elements and direct transcriptional targets including canonical WNT- and NOTCH-responsive genes. Analysis of human intestinal tissues showed increased levels of KLF5 in the regenerating epithelium as compared to those of healthy controls.

Conclusion: We conclude that ISC self-renewal, lineage specification, and precursor dedifferentiation require KLF5, by its ability to regulate epigenetic and transcriptional activities of ISC-specific gene sets. These findings have the potential for modulating ISC functions by targeting KLF5 in the intestinal epithelium.
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http://dx.doi.org/10.1016/j.jcmgh.2019.11.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7078555PMC
November 2019

The Novel Small-Molecule SR18662 Efficiently Inhibits the Growth of Colorectal Cancer and .

Mol Cancer Ther 2019 11 29;18(11):1973-1984. Epub 2019 Jul 29.

Department of Medicine, Stony Brook University School of Medicine, Stony Brook, New York.

Krüppel-like factor 5 (KLF5), a member of the SP/KLF family of zinc finger transcription factors, is overexpressed in human colorectal cancer specimens, and this overabundance is associated with aggressive cancer development and progression. We demonstrated that mice haploinsufficient for had reduced intestinal tumor burden in the background of germline mutation in , a gatekeeper of intestinal tumorigenesis. Based on a high-throughput screening strategy, we developed ML264, a small-molecule compound that inhibits KLF5, and showed that it inhibits growth of colorectal cancer and Through optimization efforts based on the structure of ML264, we have now identified a new lead compound, SR18662. We find that treatment with SR18662 significantly reduces growth and proliferation of colorectal cancer cells as compared with treatment with vehicle control, ML264, or SR15006 (a less optimized analogue from SAR efforts leading to SR18662). SR18662 showed improved efficacy in reducing the viability of multiple colorectal cancer cell lines. Flow cytometry analysis following SR18662 treatment showed an increase in cells captured in either S or G-M phases of the cell cycle and a significant increase in the number of apoptotic cells, the latter a unique property compared with ML264 or SR15006. SR18662 treatment also reduces the expression of cyclins and components of the MAPK and WNT signaling pathways. Importantly, we observed a significant dose-dependent inhibition of xenograft growth in mice following SR18662 treatment that exceeded the effect of ML264 at equivalent doses. These findings support further development of SR18662 and its analogues for colorectal cancer therapy.
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http://dx.doi.org/10.1158/1535-7163.MCT-18-1366DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6825545PMC
November 2019

Oncogenic KRAS Reduces Expression of FGF21 in Acinar Cells to Promote Pancreatic Tumorigenesis in Mice on a High-Fat Diet.

Gastroenterology 2019 11 25;157(5):1413-1428.e11. Epub 2019 Jul 25.

Department of Medicine, Stony Brook University, Stony Brook, New York; Department of Gastrointestinal Medical Oncology, University of Texas, MD Anderson Cancer Center, Houston, Texas. Electronic address:

Background & Aims: Obesity is a risk factor for pancreatic cancer. In mice, a high-fat diet (HFD) and expression of oncogenic KRAS lead to development of invasive pancreatic ductal adenocarcinoma (PDAC) by unknown mechanisms. We investigated how oncogenic KRAS regulates the expression of fibroblast growth factor 21, FGF21, a metabolic regulator that prevents obesity, and the effects of recombinant human FGF21 (rhFGF21) on pancreatic tumorigenesis.

Methods: We performed immunohistochemical analyses of FGF21 levels in human pancreatic tissue arrays, comprising 59 PDAC specimens and 45 nontumor tissues. We also studied mice with tamoxifen-inducible expression of oncogenic KRAS in acinar cells (Kras mice) and fElas mice (controls). Kras mice were placed on an HFD or regular chow diet (control) and given injections of rhFGF21 or vehicle; pancreata were collected and analyzed by histology, immunoblots, quantitative polymerase chain reaction, and immunohistochemistry. We measured markers of inflammation in the pancreas, liver, and adipose tissue. Activity of RAS was measured based on the amount of bound guanosine triphosphate.

Results: Pancreatic tissues of mice expressed high levels of FGF21 compared with liver tissues. FGF21 and its receptor proteins were expressed by acinar cells. Acinar cells that expressed Kras had significantly lower expression of Fgf21 messenger RNA compared with acinar cells from control mice, partly due to down-regulation of PPARG expression-a transcription factor that activates Fgf21 transcription. Pancreata from Kras mice on a control diet and given injections of rhFGF21 had reduced pancreatic inflammation, infiltration by immune cells, and acinar-to-ductal metaplasia compared with mice given injections of vehicle. HFD-fed Kras mice given injections of vehicle accumulated abdominal fat, developed extensive inflammation, pancreatic cysts, and high-grade pancreatic intraepithelial neoplasias (PanINs); half the mice developed PDAC with liver metastases. HFD-fed Kras mice given injections of rhFGF21 had reduced accumulation of abdominal fat and pancreatic triglycerides, fewer pancreatic cysts, reduced systemic and pancreatic markers of inflammation, fewer PanINs, and longer survival-only approximately 12% of the mice developed PDACs, and none of the mice had metastases. Pancreata from HFD-fed Kras mice given injections of rhFGF21 had lower levels of active RAS than from mice given vehicle.

Conclusions: Normal acinar cells from mice and humans express high levels of FGF21. In mice, acinar expression of oncogenic KRAS significantly reduces FGF21 expression. When these mice are placed on an HFD, they develop extensive inflammation, pancreatic cysts, PanINs, and PDACs, which are reduced by injection of FGF21. FGF21 also reduces the guanosine triphosphate binding capacity of RAS. FGF21 might be used in the prevention or treatment of pancreatic cancer.
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http://dx.doi.org/10.1053/j.gastro.2019.07.030DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6815712PMC
November 2019

Obesogenic high-fat diet heightens aerobic glycolysis through hyperactivation of oncogenic KRAS.

Cell Commun Signal 2019 02 28;17(1):19. Epub 2019 Feb 28.

Division of Gastroenterology and Hepatology, Department of Medicine, Stony Brook of University School of Medicine, Stony Brook, New York, 11794, USA.

Oncogenic KRAS plays a vital role in controlling tumor metabolism by enhancing aerobic glycolysis. Obesity driven by chronic consumption of high-fat diet (HFD) is a major risk factor for oncogenic KRAS-mediated pancreatic ductal adenocarcinoma (PDAC). However, the role of HFD in KRAS-mediated metabolic reprogramming has been obscure. Here, by using genetically engineered mouse models expressing an endogenous level of KRAS in pancreatic acinar cells, we demonstrate that hyperactivation of KRAS by obesogenic HFD, as compared to carbohydrate-rich diet, is responsible for enhanced aerobic glycolysis that associates with critical pathogenic responses in the path towards PDAC. Ablation of Cox-2 attenuates KRAS hyperactivation leading to the reversal of both aggravated aerobic glycolysis and high-grade dysplasia under HFD challenge. Our data highlight a pivotal role of the cooperative interaction between obesity-ensuing HFD and oncogenic KRAS in driving the heightened aerobic glycolysis during pancreatic tumorigenesis and suggest that in addition to directly targeting KRAS and aerobic glycolysis pathway, strategies to target the upstream of KRAS hyperactivation may bear important therapeutic value.
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http://dx.doi.org/10.1186/s12964-019-0333-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6396546PMC
February 2019

Loss of the Krüppel-like factor 4 tumor suppressor is associated with epithelial-mesenchymal transition in colorectal cancer.

J Cancer Metastasis Treat 2019 26;5. Epub 2019 Nov 26.

Department of Medicine, Stony Brook University School of Medicine, Stony Brook, NY 11794, USA.

Aim: Colorectal cancer (CRC) is the third leading cancer-related cause of death due to its propensity to metastasize. Epithelial-mesenchymal transition (EMT) is a multistep process important for invasion and metastasis of CRC. Krüppel-like factor 4 (KLF4) is a zinc finger transcription factor highly expressed in differentiated cells of the intestinal epithelium. KLF4 has been shown to play a tumor suppressor role during CRC tumorigenesis - its loss accelerates development and progression of cancer. The present study examined the relationship between KLF4 and markers of EMT in CRC.

Methods: Immunofluorescence staining for KLF4 and EMT markers was performed on archived patient samples after colorectal cancer resection and on colonic tissues of mice with colitis-associated cancer.

Results: We found that KLF4 expression is lost in tumor sections obtained from CRC patients and in those of mouse colon following azoxymethane and dextran sodium sulfate (AOM/DSS) treatment when compared to their respective normal appearing mucosa. Importantly, in CRC patient tumor sections, we observed a negative correlation between KLF4 levels and mesenchymal markers including TWIST, β-catenin, claudin-1, N-cadherin, and vimentin. Similarly, in tumor tissues from AOM/DSS-treated mice, KLF4 levels were negatively correlated with mesenchymal markers including SNAI2, β-catenin, and vimentin and positively correlated with the epithelial marker E-cadherin.

Conclusion: These findings suggest that the loss of KLF4 expression is a potentially significant indicator of EMT in CRC.
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http://dx.doi.org/10.20517/2394-4722.2019.35DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7304562PMC
November 2019

Podocyte-Specific Induction of Krüppel-Like Factor 15 Restores Differentiation Markers and Attenuates Kidney Injury in Proteinuric Kidney Disease.

J Am Soc Nephrol 2018 10 24;29(10):2529-2545. Epub 2018 Aug 24.

Divisions of Nephrology and

Background: Podocyte injury is the hallmark of proteinuric kidney diseases, such as FSGS and minimal change disease, and destabilization of the podocyte's actin cytoskeleton contributes to podocyte dysfunction in many of these conditions. Although agents, such as glucocorticoids and cyclosporin, stabilize the actin cytoskeleton, systemic toxicity hinders chronic use. We previously showed that loss of the kidney-enriched zinc finger transcription factor Krüppel-like factor 15 (KLF15) increases susceptibility to proteinuric kidney disease and attenuates the salutary effects of retinoic acid and glucocorticoids in the podocyte.

Methods: We induced podocyte-specific in two proteinuric murine models, HIV-1 transgenic () mice and adriamycin (ADR)-induced nephropathy, and used RNA sequencing of isolated glomeruli and subsequent enrichment analysis to investigate pathways mediated by podocyte-specific in mice. We also explored in cultured human podocytes the potential mediating role of Wilms Tumor 1 (WT1), a transcription factor critical for podocyte differentiation.

Results: In mice, inducing podocyte-specific attenuated podocyte injury, glomerulosclerosis, tubulointerstitial fibrosis, and inflammation, while improving renal function and overall survival; it also attenuated podocyte injury in ADR-treated mice. Enrichment analysis of RNA sequencing from the mouse model shows that induction activates pathways involved in stabilization of actin cytoskeleton, focal adhesion, and podocyte differentiation. Transcription factor enrichment analysis, with further experimental validation, suggests that KLF15 activity is in part mediated by WT1.

Conclusions: Inducing podocyte-specific attenuates kidney injury by directly and indirectly upregulating genes critical for podocyte differentiation, suggesting that induction might be a potential strategy for treating proteinuric kidney disease.
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http://dx.doi.org/10.1681/ASN.2018030324DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6171275PMC
October 2018

Podocyte-Specific Loss of Krüppel-Like Factor 6 Increases Mitochondrial Injury in Diabetic Kidney Disease.

Diabetes 2018 11 16;67(11):2420-2433. Epub 2018 Aug 16.

Division of Nephrology, Department of Medicine, Stony Brook University, Stony Brook, NY

Mitochondrial injury is uniformly observed in several murine models as well as in individuals with diabetic kidney disease (DKD). Although emerging evidence has highlighted the role of key transcriptional regulators in mitochondrial biogenesis, little is known about the regulation of mitochondrial cytochrome c oxidase assembly in the podocyte under diabetic conditions. We recently reported a critical role of the zinc finger Krüppel-like factor 6 (KLF6) in maintaining mitochondrial function and preventing apoptosis in a proteinuric murine model. In this study, we report that podocyte-specific knockdown of increased the susceptibility to streptozotocin-induced DKD in the resistant C57BL/6 mouse strain. We observed that the loss of in podocytes reduced the expression of with resultant increased mitochondrial injury, leading to activation of the intrinsic apoptotic pathway under diabetic conditions. Conversely, mitochondrial injury and apoptosis were significantly attenuated with overexpression of in cultured human podocytes under hyperglycemic conditions. Finally, we observed a significant reduction in glomerular and podocyte-specific expression of KLF6 in human kidney biopsies with progression of DKD. Collectively, these data suggest that podocyte-specific KLF6 is critical to preventing mitochondrial injury and apoptosis under diabetic conditions.
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http://dx.doi.org/10.2337/db17-0958DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6198342PMC
November 2018

Increased Genetic Instability and Accelerated Progression of Colitis-Associated Colorectal Cancer through Intestinal Epithelium-specific Deletion of .

Mol Cancer Res 2019 01 14;17(1):165-176. Epub 2018 Aug 14.

Department of Medicine, Stony Brook University School of Medicine, Stony Brook, New York.

Krüppel-like factor 4 (KLF4), a zinc finger transcription factor, regulates homeostasis of the intestinal epithelium. Previously, it was reported that KLF4 functions as a tumor suppressor in colorectal cancer. Here, evidence demonstrates that KLF4 mitigates the development and progression of colitis-associated colorectal cancer (CAC) in a murine model. Mice with intestinal epithelium-specific deletion of ( ) and control mice ( ) were used to explore the role of KLF4 in the development of azoxymethane (AOM) and dextran sodium sulfate (DSS)-induced CAC. Upon AOM and DSS treatment, KLF4 expression was progressively lost in colonic tissues of mice during tumor development. mice treated with AOM/DSS developed significantly more adenomatous polyps and carcinomas in comparison with treated mice. Adenomatous polyps, but not normal-appearing mucosa, from colonic tissues of treated mice contained a significantly increased number of mitotic cells with more than 2 centrosomes relative to treated control mice. KLF4 and p53 colocalize to the centrosomes in mouse embryonic fibroblasts (MEF). Absence of KLF4 in MEFs inhibits and its overexpression restores p53 localization to the centrosomes in MEFs. IMPLICATIONS: Taken together, these results indicate that KLF4 plays a protective role against progression of CAC by guarding against genetic instability.
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http://dx.doi.org/10.1158/1541-7786.MCR-18-0399DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6318049PMC
January 2019

Krüppel-like factor 4 is a negative regulator of STAT3-induced glomerular epithelial cell proliferation.

JCI Insight 2018 06 21;3(12). Epub 2018 Jun 21.

Division of Nephrology, Department of Medicine, Stony Brook University, Stony Brook, New York, USA.

Pathologic glomerular epithelial cell (GEC) hyperplasia is characteristic of both rapidly progressive glomerulonephritis (RPGN) and subtypes of focal segmental glomerulosclerosis (FSGS). Although initial podocyte injury resulting in activation of STAT3 signals GEC proliferation in both diseases, mechanisms regulating this are unknown. Here, we show that the loss of Krüppel-like factor 4 (KLF4), a zinc-finger transcription factor, enhances GEC proliferation in both RPGN and FSGS due to dysregulated STAT3 signaling. We observed that podocyte-specific knockdown of Klf4 (C57BL/6J) increased STAT3 signaling and exacerbated crescent formation after nephrotoxic serum treatment. Interestingly, podocyte-specific knockdown of Klf4 in the FVB/N background alone was sufficient to activate STAT3 signaling, resulting in FSGS with extracapillary proliferation, as well as renal failure and reduced survival. In cultured podocytes, loss of KLF4 resulted in STAT3 activation and cell-cycle reentry, leading to mitotic catastrophe. This triggered IL-6 release into the supernatant, which activated STAT3 signaling in parietal epithelial cells. Conversely, either restoration of KLF4 expression or inhibition of STAT3 signaling improved survival in KLF4-knockdown podocytes. Finally, human kidney biopsy specimens with RPGN exhibited reduced KLF4 expression with a concomitant increase in phospho-STAT3 expression as compared with controls. Collectively, these results suggest the essential role of KLF4/STAT3 signaling in podocyte injury and its regulation of aberrant GEC proliferation.
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http://dx.doi.org/10.1172/jci.insight.98214DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6124441PMC
June 2018

KLF5 mediates the hyper-proliferative phenotype of the intestinal epithelium in mice with intestine-specific endogenous K-Ras expression.

Am J Cancer Res 2018 1;8(4):723-731. Epub 2018 Apr 1.

Department of Medicine, School of Medicine, Stony Brook University, Stony Brook NY 11794, USA.

Oncogenic activation is a common mutational event in colorectal cancer. We previously showed that transcription factor, Krüppel-like factor 5 (KLF5), contributes to intestinal polyposis in mice with activation. At 14 months of age, mice developed small intestinal and colonic hyperplastic polyps while had none. The intestinal crypts of mice contained a higher number of mitotic figures and increased crypt heights compared to controls. The intestinal epithelium of mice showed prolific KLF5 expression throughout and above the elongated crypts. In contrast, KLF5 expression was limited to the upper crypt region in the controls. The levels of K-Ras effectors were significantly increased in as compared to controls. The mice showed decreased survival upon treatment with azoxymethane (AOM) as compared to controls. Furthermore, loss of one of alleles reduced levels of K-Ras effector proteins and prevented mortality of mice upon AOM treatment. The mice spontaneously develop hyperplastic intestinal polyps and display a hyper-proliferative intestinal phenotype with elongated crypts, increased numbers of mitotic figures, elevated expression of KLF5, and other pro-proliferative targets. Induction of colonic tumorigenesis with AOM is detrimental to mice that is in part dependent of KLF5.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5934562PMC
April 2018

Correction to: The Role of Intestinal Stem Cells in Epithelial Regeneration Following Radiation-Induced Gut Injury.

Curr Stem Cell Rep 2018;4(1):95. Epub 2018 Feb 19.

1Department of Medicine, Stony Brook University School of Medicine, HSC T-17, Rm. 090, Stony Brook, NY 11794 USA.

[This corrects the article DOI: 10.1007/s40778-017-0103-7.].
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http://dx.doi.org/10.1007/s40778-018-0121-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5866267PMC
February 2018

Krüppel-like Factor 5, Increased in Pancreatic Ductal Adenocarcinoma, Promotes Proliferation, Acinar-to-Ductal Metaplasia, Pancreatic Intraepithelial Neoplasia, and Tumor Growth in Mice.

Gastroenterology 2018 04 15;154(5):1494-1508.e13. Epub 2017 Dec 15.

Department of Medicine, Stony Brook University School of Medicine, Stony Brook, New York. Electronic address:

Background & Aims: Activating mutations in KRAS are detected in most pancreatic ductal adenocarcinomas (PDACs). Expression of an activated form of KRAS (KrasG12D) in pancreata of mice is sufficient to induce formation of pancreatic intraepithelial neoplasia (PanINs)-a precursor of PDAC. Pancreatitis increases formation of PanINs in mice that express KrasG12D by promoting acinar-to-ductal metaplasia (ADM). We investigated the role of the transcription factor Krüppel-like factor 5 (KLF5) in ADM and KRAS-mediated formation of PanINs.

Methods: We performed studies in adult mice with conditional disruption of Klf5 (Klf5) and/or expression of Kras (LSL-Kras) via Cre recombinase regulated by an acinar cell-specific promoter (Ptf1a). Activation of Kras and loss of KLF5 was achieved by administration of tamoxifen. Pancreatitis was induced in mice by administration of cerulein; pancreatic tissues were collected, analyzed by histology and immunohistochemistry, and transcriptomes were compared between mice that did or did not express KLF5. We performed immunohistochemical analyses of human tissue microarrays, comparing levels of KLF5 among 96 human samples of PDAC. UN-KC-6141 cells (pancreatic cancer cells derived from Pdx1-Cre;LSL-Kras mice) were incubated with inhibitors of different kinases and analyzed in proliferation assays and by immunoblots. Expression of KLF5 was knocked down with small hairpin RNAs or CRISPR/Cas9 strategies; cells were analyzed in proliferation and gene expression assays, and compared with cells expressing control vectors. Cells were subcutaneously injected into flanks of syngeneic mice and tumor growth was assessed.

Results: Of the 96 PDAC samples analyzed, 73% were positive for KLF5 (defined as nuclear staining in more than 5% of tumor cells). Pancreata from Ptf1a-Cre;LSL-Kras mice contained ADM and PanIN lesions, which contained high levels of nuclear KLF5 within these structures. In contrast, Ptf1a-Cre;LSL-Kras;Klf5 mice formed fewer PanINs. After cerulein administration, Ptf1a-Cre;LSL-Kras mice formed more extensive ADM than Ptf1a-Cre;LSL-Kras;Klf5 mice. Pancreata from Ptf1a-Cre;LSL-Kras;Klf5 mice had increased expression of the tumor suppressor NDRG2 and reduced phosphorylation (activation) of STAT3, compared with Ptf1a-Cre;LSL-Kras mice. In UN-KC-6141 cells, PI3K and MEK signaling increased expression of KLF5; a high level of KLF5 increased proliferation. Cells with knockdown of Klf5 had reduced proliferation, compared with control cells, had reduced expression of ductal markers, and formed smaller tumors (71.61 ± 30.79 mm vs 121.44 ± 34.90 mm from control cells) in flanks of mice.

Conclusion: Levels of KLF5 are increased in human PDAC samples and in PanINs of Ptf1a-Cre;LSL-Kras mice, compared with controls. KLF5 disruption increases expression of NDRG2 and reduces activation of STAT3 and reduces ADM and PanINs formation in mice. Strategies to reduce KLF5 activity might reduce progression of acinar cells from ADM to PanIN and pancreatic tumorigenesis.
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http://dx.doi.org/10.1053/j.gastro.2017.12.005DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5880723PMC
April 2018

Krüppel-like factor 5 is essential for maintenance of barrier function in mouse colon.

Am J Physiol Gastrointest Liver Physiol 2017 Nov 1;313(5):G478-G491. Epub 2017 Sep 1.

Department of Medicine, Stony Brook University School of Medicine, Stony Brook, New York;

Krüppel-like factor 5 (KLF5) is a member of the zinc finger family of transcription factors that regulates homeostasis of the intestinal epithelium. Previous studies suggested an indispensable role of KLF5 in maintaining intestinal barrier function. In the current study, we investigated the mechanisms by which KLF5 regulates colonic barrier function in vivo and in vitro. We used an inducible and a constitutive intestine-specific knockout mouse models ( designated as and as ) and studied an inducible knockdown in Caco-2 BBe cells using a lentiviral Tet-on system (Caco-2 BBe ). Specific knockout of in colonic tissues, either inducible or constitutive, resulted in increased intestinal permeability. The phenotype was accompanied by a significant reduction in , which encodes desmoglein-2, a desmosomal cadherin, at both mRNA and protein levels. Transmission electron microscopy showed alterations of desmosomal morphology in both knockdown Caco-2 BBe cells and knockout mouse colonic tissues. Inducible knockdown of in Caco-2BBe cells grown on Transwell plates led to impaired barrier function as evidenced by decreased transepithelial electrical resistance and increased paracellular permeability to fluorescein isothiocyanate-4 kDa dextran. Furthermore, DSG2 was significantly decreased in knockdown cells, and DSG2 overexpression partially rescued the impaired barrier function caused by knockdown. Electron microscopy studies demonstrated altered desmosomal morphology after knockdown. In combination with chromatin immunoprecipitation analysis and promoter study, our data show that KLF5 regulates intestinal barrier function by mediating the transcription of , a gene encoding a major component of desmosome structures. The study is original research on the direct function of a Krüppel-like factor on intestinal barrier function, which is commonly exerted by cell junctions, including tight junctions, adherens junctions, and desmosomes. Numerous previous studies were focused on tight junctions and adherens junctions. However, this study provided a new perspective on how the intestinal barrier function is regulated by KLF5 through DSG2, a component of desmosome complexes.
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http://dx.doi.org/10.1152/ajpgi.00172.2017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5792213PMC
November 2017

Kruppel-like factor 4 regulates matrix metalloproteinase and aggrecanase gene expression in chondrocytes.

Cell Tissue Res 2017 12 31;370(3):441-449. Epub 2017 Aug 31.

Department of Oral Anatomy and Developmental Biology, Osaka University Graduate School of Dentistry, 1-8 Yamada-oka, Suita, Osaka, 565-0871, Japan.

Kruppel-like factor 4 (KLF4) is a zinc finger transcription factor that plays crucial roles during the development and maintenance of multiple organs. We and others have previously shown that KLF4 is involved in bone modeling and remodeling but roles played by KLF4 during skeletogenesis are still not fully understood. Here, we show that KLF4 is expressed in the epiphyseal growth plate and articular chondrocytes. Most articular chondrocytes expressed KLF4 in embryos but it localized only in a subset of superficial zone cells in postnatal mice. When KLF4 was overexpressed in chondrocytes in vitro, it severely repressed chondrocytic gene expressions. Global gene expression profiling of KLF4-transduced chondrocytes revealed matrix degrading proteinases of the matrix metalloproteinase and disintegrin and metalloproteinase with thrombospondin-1 domain families within the group of upregulated genes. Proteinase induction by KLF4 was alleviated by Trichostatin A treatment suggesting the possible involvement of epigenetic mechanisms on proteinase induction by KLF4. These results indicate the possible involvement of KLF4 in physiological and pathological aspects during cartilage development and maintenance.
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http://dx.doi.org/10.1007/s00441-017-2674-0DOI Listing
December 2017

The loss of Krüppel-like factor 15 in Foxd1 stromal cells exacerbates kidney fibrosis.

Kidney Int 2017 11 24;92(5):1178-1193. Epub 2017 Jun 24.

Kidney Institute of PLA, Department of Medicine, Changzheng Hospital, Second Military Medical University, Shanghai 200003, People's Republic of China. Electronic address:

Large epidemiological studies clearly demonstrate that multiple episodes of acute kidney injury contribute to the development and progression of kidney fibrosis. Although our understanding of kidney fibrosis has improved in the past two decades, we have limited therapeutic strategies to halt its progression. Myofibroblast differentiation and proliferation remain critical to the progression of kidney fibrosis. Although canonical Wnt signaling can trigger the activation of myofibroblasts in the kidney, mediators of Wnt inhibition in the resident progenitor cells are unclear. Recent studies demonstrate that the loss of a Krüppel-like factor 15 (KLF15), a kidney-enriched zinc-finger transcription factor, exacerbates kidney fibrosis in murine models. Here, we tested whether Klf15 mRNA and protein expression are reduced in late stages of fibrosis in mice that underwent unilateral ureteric obstruction, a model of progressive renal fibrosis. Knockdown of Klf15 in Foxd1-expressing cells (Foxd1-Cre Klf15fl/fl) increased extracellular matrix deposition and myofibroblast proliferation as compared to wildtype (Foxd1-Cre Klf15+/+) mice after three and seven days of ureteral obstruction. This was validated in mice receiving angiotensin II treatment for six weeks. In both these murine models, the increase in renal fibrosis was found in Foxd1-Cre Klf15 mice and accompanied by the activation of Wnt/β-catenin signaling. Furthermore, knockdown of Klf15 in cultured mouse embryonic fibroblasts activated canonical Wnt/β-catenin signaling, increased profibrotic transcripts, and increased proliferation after treatment with a Wnt1 ligand. Conversely, the overexpression of KLF15 inhibited phospho-β-catenin (Ser552) expression in Wnt1-treated cells. Thus, KLF15 has a critical role in attenuating kidney fibrosis by inhibiting the canonical Wnt/β-catenin pathway.
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http://dx.doi.org/10.1016/j.kint.2017.03.037DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5651204PMC
November 2017

DNA Methyltransferases Modulate Hepatogenic Lineage Plasticity of Mesenchymal Stromal Cells.

Stem Cell Reports 2017 07 8;9(1):247-263. Epub 2017 Jun 8.

Taipei City Hospital, Taipei 10341, Taiwan; Institute of Clinical Medicine, National Yang-Ming University, Taipei 11221, Taiwan; Stem Cell Research Center, National Yang-Ming University, Taipei 11221, Taiwan; Department of Medical Research, Taipei Veterans General Hospital, Taipei 11221, Taiwan. Electronic address:

The irreversibility of developmental processes in mammalian cells has been challenged by rising evidence that de-differentiation of hepatocytes occurs in adult liver. However, whether reversibility exists in mesenchymal stromal cell (MSC)-derived hepatocytes (dHeps) remains elusive. In this study, we find that hepatogenic differentiation (HD) of MSCs is a reversible process and is modulated by DNA methyltransferases (DNMTs). DNMTs are regulated by transforming growth factor β1 (TGFβ1), which in turn controls hepatogenic differentiation and de-differentiation. In addition, a stepwise reduction in TGFβ1 concentrations in culture media increases DNMT1 and decreases DNMT3 in primary hepatocytes (Heps) and confers Heps with multi-differentiation potentials similarly to MSCs. Hepatic lineage reversibility of MSCs and lineage conversion of Heps are regulated by DNMTs in response to TGFβ1. This previously unrecognized TGFβ1-DNMTs-MSC-HD axis may further increase the understanding the normal and pathological processes in the liver, as well as functions of MSCs after transplantation to treat liver diseases.
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http://dx.doi.org/10.1016/j.stemcr.2017.05.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5511371PMC
July 2017

SP and KLF Transcription Factors in Digestive Physiology and Diseases.

Gastroenterology 2017 06 30;152(8):1845-1875. Epub 2017 Mar 30.

Department of Medicine, Stony Brook University School of Medicine, Stony Brook, New York; Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, New York. Electronic address:

Specificity proteins (SPs) and Krüppel-like factors (KLFs) belong to the family of transcription factors that contain conserved zinc finger domains involved in binding to target DNA sequences. Many of these proteins are expressed in different tissues and have distinct tissue-specific activities and functions. Studies have shown that SPs and KLFs regulate not only physiological processes such as growth, development, differentiation, proliferation, and embryogenesis, but pathogenesis of many diseases, including cancer and inflammatory disorders. Consistently, these proteins have been shown to regulate normal functions and pathobiology in the digestive system. We review recent findings on the tissue- and organ-specific functions of SPs and KLFs in the digestive system including the oral cavity, esophagus, stomach, small and large intestines, pancreas, and liver. We provide a list of agents under development to target these proteins.
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http://dx.doi.org/10.1053/j.gastro.2017.03.035DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5815166PMC
June 2017

Krüppel-like factors in mammalian stem cells and development.

Development 2017 03;144(5):737-754

Division of Nephrology, Department of Medicine, Stony Brook University School of Medicine, Stony Brook, NY 11794-8176, USA

Krüppel-like factors (KLFs) are a family of zinc-finger transcription factors that are found in many species. Recent studies have shown that KLFs play a fundamental role in regulating diverse biological processes such as cell proliferation, differentiation, development and regeneration. Of note, several KLFs are also crucial for maintaining pluripotency and, hence, have been linked to reprogramming and regenerative medicine approaches. Here, we review the crucial functions of KLFs in mammalian embryogenesis, stem cell biology and regeneration, as revealed by studies of animal models. We also highlight how KLFs have been implicated in human diseases and outline potential avenues for future research.
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http://dx.doi.org/10.1242/dev.145441DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5374354PMC
March 2017

Krüppel-like factor 4 (KLF4): What we currently know.

Gene 2017 May 22;611:27-37. Epub 2017 Feb 22.

Department of Medicine, Stony Brook University, Stony Brook, NY 11794, USA; Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY 11794, USA. Electronic address:

Krüppel-like factor 4 (KLF4) is an evolutionarily conserved zinc finger-containing transcription factor that regulates diverse cellular processes such as cell growth, proliferation, and differentiation. Since its discovery in 1996, KLF4 has been gaining a lot of attention, particularly after it was shown in 2006 as one of four factors involved in the induction of pluripotent stem cells (iPSCs). Here we review the current knowledge about the different functions and roles of KLF4 in various tissue and organ systems.
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http://dx.doi.org/10.1016/j.gene.2017.02.025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5391259PMC
May 2017

The Role of Intestinal Stem Cells in Epithelial Regeneration Following Radiation-Induced Gut Injury.

Curr Stem Cell Rep 2017 5;3(4):320-332. Epub 2017 Oct 5.

1Department of Medicine, Stony Brook University School of Medicine, HSC T-17, Rm. 090, Stony Brook, NY 11794 USA.

Purpose Of Review: Intestinal epithelial cells show remarkable plasticity in regenerating the epithelium following radiation injury. In this review, we explore the regenerative capacity and mechanisms of various populations of intestinal stem cells (ISCs) in response to ionizing radiation.

Recent Findings: Ionizing radiation targets mitotic cells that include "active" ISCs and progenitor cells. Lineage-tracing experiments showed that several different cell types identified by a single or combination of markers are capable of regenerating the epithelium, confirming that ISCs exhibit a high degree of plasticity. However, the identities of the contributing cells marked by various markers require further validation.

Summary: Following radiation injury, quiescent and/or radioresistant cells become active stem cells to regenerate the epithelium. Looking forward, understanding the mechanisms by which ISCs govern tissue regeneration is crucial to determine therapeutic approaches to promote intestinal epithelial regeneration following injury.
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http://dx.doi.org/10.1007/s40778-017-0103-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5818549PMC
October 2017

Epithelial derived-matrix metalloproteinase (MMP9) exhibits a novel defensive role of tumor suppressor in colitis associated cancer by activating MMP9-Notch1-ARF-p53 axis.

Oncotarget 2017 Jan;8(1):364-378

Institute for Biomedical Sciences, Georgia State University, Atlanta, GA, USA.

Colitis associated cancer (CAC) is chronic inflammation driven colon cancer, prevalent among individuals with Inflammatory Bowel Disease. Matrix-metalloproteinase (MMP9) is one of the essential regulators of extra cellular matrix components. We have shown that MMP9 is protective in CAC contrary to its inflammatory role in acute-colitis. Aim of our study is to identify the mechanism of the protective role of epithelial derived-MMP9 in CAC. We used homozygous transgenic mice constitutively-expressing MMP9 in colonic-epithelium (TgM9) and wild-type (WT) littermates for in vivo experiments. Stably-transfected HCT116 with/without MMP9, and mouse embryonic-fibroblasts (WT and MMP9-/-, MEFs) were used for in vitro experiments. TgM9 mice exhibited less tumor burden, increased apoptosis, and increased expressions of active-Notch1, p53, p21WAF1/Cip1, caspase-3 and cyclin E in CAC compared to WTs. These results were supported by MEFs data. HCT116-cells overexpressing MMP9 indicated decreased cell proliferation, S-phase cell-cycle arrest and less DNA damage compared to vector. MMP9-/- mice showed attenuation of MMP9 was directly associated with p19ARF. Our study identifies the tumor suppressor role of epithelial derived-MMP9 in CAC via novel mechanistic pathway "MMP9-Notch1-ARF-p53 axis" regulating apoptosis, cell-cycle arrest and DNA damage implying, that MMP9 expression might be a natural/biological way to suppress colonic ulceration due to chronic inflammation.
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http://dx.doi.org/10.18632/oncotarget.13406DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5352126PMC
January 2017

Intestinal stem cell resurgence by enterocyte precursors.

Stem Cell Investig 2016 23;3:49. Epub 2016 Sep 23.

Department of Medicine, Stony Brook University School of Medicine, Stony Brook, NY, USA;; Department of Physiology and Biophysics, Stony Brook University School of Medicine, Stony Brook, NY, USA.

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http://dx.doi.org/10.21037/sci.2016.09.01DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5067364PMC
September 2016

Role of neutral ceramidase in colon cancer.

FASEB J 2016 12 8;30(12):4159-4171. Epub 2016 Sep 8.

Department of Medicine, Stony Brook University, New York, USA;

Alterations in sphingolipid metabolism, especially ceramide and sphingosine 1-phosphate, have been linked to colon cancer, suggesting that enzymes of sphingolipid metabolism may emerge as novel regulators and targets in colon cancer. Neutral ceramidase (nCDase), a key enzyme in sphingolipid metabolism that hydrolyzes ceramide into sphingosine, is highly expressed in the intestine; however, its role in colon cancer has not been defined. Here we show that molecular and pharmacological inhibition of nCDase in colon cancer cells increases ceramide, and this is accompanied by decreased cell survival and increased apoptosis and autophagy, with minimal effects on noncancerous cells. Inhibition of nCDase resulted in loss of β-catenin and inhibition of ERK, components of pathways relevant for colon cancer development. Furthermore, inhibition of nCDase in a xenograft model delayed tumor growth and increased ceramide while decreasing proliferation. It is noteworthy that mice lacking nCDase treated with azoxymethane were protected from tumor formation. Taken together, these studies show that nCDase is pivotal for regulating initiation and development of colon cancer, and these data suggest that this enzyme is a suitable and novel target for colon cancer therapy.-García-Barros, M., Coant, N., Kawamori, T., Wada, M., Snider, A. J., Truman, J.-P., Wu, B. X., Furuya, H., Clarke, C. J., Bialkowska, A. B., Ghaleb, A., Yang, V. W., Obeid, L. M., Hannun, Y. A. Role of neutral ceramidase in colon cancer.
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http://dx.doi.org/10.1096/fj.201600611RDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5102116PMC
December 2016

Improved Swiss-rolling Technique for Intestinal Tissue Preparation for Immunohistochemical and Immunofluorescent Analyses.

J Vis Exp 2016 07 13(113). Epub 2016 Jul 13.

Department of Medicine, Stony Brook University School of Medicine; Department of Physiology & Biophysics, Stony Brook University School of Medicine;

Understanding the role of factors that regulate intestinal epithelial homeostasis and response to injury and regeneration is important. The current literature describes several different methodological approaches to obtain images of intestinal tissues for data validation. In this paper, we delineate a common protocol relating to the derivation and processing of mouse intestinal tissues. Proper fixation of intestinal tissues and Swiss-roll techniques that enhance intestinal epithelial morphology are discussed. Postresection processing and reorientation of embedded intestinal tissues are critical in obtaining paraffin-embedded blocks that display intact intestinal structural features after sectioning. The Swiss-rolling technique helps in histological assessment of the complete intestinal or colonic sections examined. An ability to differentiate intestinal structural features can be vital in quantitative measurements of intestinal inflammation and tumorigenesis along the entire length. Finally, paraffin-embedded sections are ideal for robust processing using both immunohistochemical and immunofluorescent detection methods. Nonfluorescent immunohistochemical sections provide a vibrant image of the tissue detailing different cellular structural features but do not provide flexibility for intracellular co-localization experiments. Multiple fluorescent channels can be appropriately utilized with immunofluorescent detection for co-localization experiments, lending support to mechanistic studies.
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http://dx.doi.org/10.3791/54161DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4993444PMC
July 2016