Publications by authors named "Kary Tsai"

7 Publications

  • Page 1 of 1

A Role for RAGE in DNA Double Strand Breaks (DSBs) Detected in Pathological Placentas and Trophoblast Cells.

Cells 2021 Apr 9;10(4). Epub 2021 Apr 9.

Lung and Placenta Research Laboratory, Department of Physiology and Developmental Biology, Brigham Young University, Provo, UT 84602, USA.

Impaired DNA damage responses are associated with several diseases, including pregnancy complications. Recent research identified an ATM-kinase dependent function for the nuclear isoform of the receptor for advanced glycation end-products (RAGE) during double strand break (DSB)-repair. RAGE contributes to end-resectioning of broken DNA sites by binding with the MRE11-Rad50-Nbs1 (MRN) complex. Placental research is limited regarding the impact of genomic instability and the mechanism for potential repair. We tested the hypothesis regarding the involvement of RAGE during the repair of placental DNA-DSBs. We first identified that the pregnancy complications of PE and preterm labor (PTL) experience loss of genomic integrity and an in vitro trophoblast cell model was used to characterize trophoblast DSBs. Colocalized immunofluorescence of γ-H2AX and RAGE support the potential involvement of RAGE in cellular responses to DNA-DSBs. Immunoblotting for both molecules in PE and PTL placenta samples and in trophoblast cells validated a connection. Co-immunoprecipitation studies revealed interactions between RAGE and pATM and MRE11 during DNA-DSBs. Reduced cellular invasion confirmed the role of genomic instability in trophoblastic function. Collectively, these experiments identified genomic instability in pregnancy complications, the impact of defective DNA on trophoblast function, and a possible RAGE-mediated mechanism during DNA-DSB repair.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/cells10040857DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8069300PMC
April 2021

Differential expression of mTOR related molecules in the placenta from gestational diabetes mellitus (GDM), intrauterine growth restriction (IUGR) and preeclampsia patients.

Reprod Biol 2021 Jun 4;21(2):100503. Epub 2021 Apr 4.

Lung and Placenta Research Laboratory, Brigham Young University, Department of Physiology and Developmental Biology, Provo, UT, USA. Electronic address:

The mechanistic target of rapamycin (mTOR) pathway is involved in the function and growth of the placenta during pregnancy. The mTOR pathway responds to nutrient availability and growth factors that regulate protein expression and cell growth. Disrupted mTOR signaling is associated with the development of several obstetric complications. The purpose of this study was to identify the differential placental expression of various mTOR-associated proteins in the placenta during normal gestation (Control), gestational diabetes mellitus (GDM), intrauterine growth restriction (IUGR) and preeclampsia (PE). Immunohistochemistry localized activated proteins (phospho; p) mTOR, pp70, p4EBP1, pAKT and pERK. Real-time PCR array was performed to show differing placental expression of additional mTOR-associated genes. Western blot was performed for pAMPK protein. We observed: 1) increased pmTOR during GDM and decreased pmTOR during IUGR and PE, 2) increased pp70 during IUGR and decreased pp70 during GDM and PE, 3) increased p4EBP1 during GDM, IUGR, and PE, 4) increased pAKT during GDM, 5) increased pERK during IUGR, 6) differential placental expression of mTOR pathway associated genes and increased pAMPK during GDM and PE. We conclude that regulation of the mTOR pathway is uniquely involved in the development of these obstetric complications. Insights into this pathway may provide avenues that if modify may help alleviate these diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.repbio.2021.100503DOI Listing
June 2021

Regulation of trophoblast cell invasion by Pyruvate Kinase isozyme M2 (PKM2).

Placenta 2021 01 15;103:24-32. Epub 2020 Oct 15.

Lung and Placenta Research Laboratory, Brigham Young University, Department of Physiology and Developmental Biology, Provo, UT, USA. Electronic address:

The Pyruvate kinase isozymes M2 (PKM2) protein is a metabolic enzyme that regulates the final step of glycolysis. This enzyme is present in highly proliferating cells and is expressed in the placenta. We recently demonstrated upregulated placental PKM2 during human intrauterine growth restriction (IUGR). Our current objective was to determine PKM2 regulation of trophoblast invasion, trophoblast PKM2 localization as well as mTOR protein expression, and to determine effects of activation of PKM2 during IUGR. Human placental tissues were obtained and analyzed by immunohistochemistry and western blot. Trophoblast cells were cultured in normoxic and hypoxic conditions and real time cell invasion and PKM2 protein were determined during activation (Fructose-6-bisphosphate; FBP6) or inhibition (Shikonin) of PKM2. In vivo studies determined the effects of PKM2 activation on placental and fetal weights. IUGR samples had elevated levels of p-PKM2. Different trophoblast PKM2 localization and expression was observed during normoxia and hypoxia. Decreased trophoblast invasion and PKM2 expression was observed during mTOR inhibition. Protection from decreased placental and fetal weights was observed by PKM2 activation. We conclude that PKM2 regulates trophoblast cell invasion depending on its subcellular location. Our results suggest that PKM2 regulation in trophoblast cells is more directly affected during hypoxia and its expression is regulated by mTOR activity. Additionally, we conclude that activation of PKM2 could reverse and/or rescue the deceased placental and fetal weights observed during IUGR. These results suggest that PKM2 could be a mediator of trophoblast cell invasion and its abundance influences the development of complicated pregnancies like IUGR.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.placenta.2020.10.019DOI Listing
January 2021

Cell invasion, RAGE expression, and inflammation in oral squamous cell carcinoma (OSCC) cells exposed to e-cigarette flavoring.

Clin Exp Dent Res 2020 12 11;6(6):618-625. Epub 2020 Aug 11.

Lung and Placenta Research Laboratory, Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, USA.

Objective: Electronic cigarettes have given rise to a new, largely unregulated market within the smoking industry. While generally supposed to be less harmful than traditional tobacco smoke, awareness of the biological effects of electronic cigarette liquid is still scarce. Our objective was to determine the impact of electronic cigarette flavoring and nicotine on gingival squamous cell carcinoma invasion, RAGE expression, and the elaboration of pro-inflammatory molecules.

Methods And Materials: Gingival and tongue squamous cell carcinoma cells were exposed to Red Hot or Green Apple flavored electronic cigarette flavoring with or without nicotine. Immunofluorescence determined RAGE expression. Real-time cellular invasion was assessed using a RTCA DP instrument. Culture medium was assayed for cytokine secretion.

Results: Compared to controls we observed: increased cell invasion in gingival cells with Red Hot electronic cigarette flavoring and decreased cell invasion with Green Apple; decreased cell invasion in tongue cells treated with Red Hot electronic cigarette flavoring and no differences in invasion with Green Apple; flavor and nicotine dependent increases in RAGE expression; and differential expression of IL-1α, IL-8, and MMP-13.

Conclusion: We conclude that electronic cigarette flavoring and nicotine orchestrate differential regulation of oral squamous cell carcinoma (OSCC) cell invasion and inflammatory effects. This study provides an important initial step in dissecting RAGE-mediated mechanisms of cancerous invasion and molecular avenues employed by OSCC.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cre2.314DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7745078PMC
December 2020

RAGE and AXL expression following secondhand smoke (SHS) exposure in mice.

Exp Lung Res 2019 Nov - Dec;45(9-10):297-309. Epub 2019 Nov 24.

Lung and Placenta Laboratory, Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, USA.

: Tobacco exposure is one of the top three global health risks leading to the development of chronic obstructive pulmonary disease (COPD). Although there is extensive research into the effects of cigarette smoke, the effect of secondhand smoke (SHS) in the lung remains limited. SHS induces receptors for advanced glycation end-products (RAGE) and an inflammatory response that leads to COPD characteristics. Semi-synthetic glycosaminoglycan ethers (SAGEs) are sulfated polysaccharides derived from hyaluronic acid that inhibit RAGE signaling. The growth arrest-specific 6 (Gas6) protein is known to induce dynamic cellular responses and is correlated with cell function. Gas6 binds to the AXL tyrosine kinase receptor and AXL-mediated signaling is implicated in proliferation and inflammation. This project's purpose was to study the correlation between RAGE, AXL, and Gas6 during SHS exposure in the lung. : C57Bl/6 mice were exposed to SHS alone or SHS + SAGEs for 4 weeks and compared to control animals exposed to room air (RA). : Compared to controls we observed: 1) increased RAGE mRNA and protein expression in SHS-exposed lungs which was decreased by SAGEs; 2) decreased expression of total AXL, but highly elevated pAXL expression following exposure; 3) highly elevated Gas6 expression when RAGE was targeted by SAGEs during SHS exposure; 4) SHS-mediated BALF cellularity and inflammatory molecule elaboration; and 5) the induction of both RAGE and AXL by Gas6 in cell culture models. : Our results suggest that there is a possible correlation between RAGE and AXL during SHS exposure. Additional research is critically needed that dissects the molecular interplay between these two important signaling cascades. At this point, the current studies provide insight into tobacco-mediated effects in the lung and clarify possible avenues for alleviating complications that could arise during SHS exposure such as those observed during COPD exacerbations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/01902148.2019.1684596DOI Listing
May 2020

Differential placental ceramide levels during gestational diabetes mellitus (GDM).

Reprod Biol Endocrinol 2019 Oct 23;17(1):81. Epub 2019 Oct 23.

Department of Physiology and Developmental Biology, Lung and Placenta Research Laboratory, Brigham Young University, 3052 LSB, Provo, UT, 84602, USA.

Background: Gestational diabetes mellitus (GDM) is associated with important factors that influence fetal development. Sphingolipids are known to be associated with the development of diabetes. Our objective was to examine ceramide, a key sphingolipid, hyperosmolarity, and apoptosis in placentas from GDM patients treated with insulin or diet.

Methods: Ceramide levels were assessed in placental tissues using immunohistochemistry. Immunoblot was performed to quantify serine palmitoyltransferase (SPT), the rate-limiting enzyme in ceramide biosynthesis, NFAT5, SMIT, AR, caspase 3 and the X-linked inhibitor of apoptosis. Trophoblast cells were treated with insulin or ceramide and assessments for mitochondrial respiration, caspase 3 and XIAP were also performed.

Results: Immunohistochemistry showed increased ceramides in the placental villous trophoblasts of the insulin-treated GDM patients. Nuclear SPT was upregulated only in the insulin-treated GDM placenta when compared to controls. Nuclear NFAT5 was also increased in the GDM placenta. Active caspase 3 was elevated in placentas from both insulin- and diet-treated GDM patients. Mitochondrial respiration was decreased in trophoblasts treated with ceramide. Active caspase was not changed while XIAP protein was increased in trophoblasts treated with ceramide.

Conclusions: Our findings confirm the presence of ceramide in the human placenta of control and GDM patients. Furthermore, we conclude that ceramide is increased in the placental trophoblast during insulin treatment and that its upregulation correlates with elevated NFAT5, SMIT, increased apoptosis and decreased trophoblast mitochondrial respiration.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12958-019-0523-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6813062PMC
October 2019

Growth arrest-specific protein-6/AXL signaling induces preeclampsia in rats†.

Biol Reprod 2020 02;102(1):199-210

Lung and Placenta Laboratory, Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, USA.

Preeclampsia (PE) is a complicated obstetric complication characterized by increased blood pressure, decreased trophoblast invasion, and inflammation. The growth arrest-specific 6 (Gas6) protein is known to induce dynamic cellular responses and is elevated in PE. Gas6 binds to the AXL tyrosine kinase receptor and AXL-mediated signaling is implicated in proliferation and migration observed in several tissues. Our laboratory utilized Gas6 to induce preeclamptic-like conditions in pregnant rats. Our objective was to determine the role of Gas6/AXL signaling as a possible model of PE. Briefly, pregnant rats were divided into three groups that received daily intraperitoneal injections (from gestational day 7.5 to 17.5) of phosphate buffered saline (PBS), Gas6, or Gas6 + R428 (an AXL inhibitor administered from gestational day 13.5 to 17.5). Animals dispensed Gas6 experienced elevated blood pressure, increased proteinuria, augmented caspase-3-mediated placental apoptosis, and diminished trophoblast invasion. Gas6 also enhanced expression of several PE-related genes and a number of inflammatory mediators. Gas6 further enhanced placental oxidative stress and impaired mitochondrial respiration. Each of these PE-related characteristics was ameliorated in dams and/or their placentae when AXL inhibition by R428 occurred in tandem with Gas6 treatment. We conclude that Gas6 signaling is capable of inducing PE and that inhibition of AXL prevents disease progression in pregnant rats. These results provide insight into pathways associated with PE that could be useful in the clarification of potential therapeutic approaches.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/biolre/ioz140DOI Listing
February 2020