Publications by authors named "Linli Li"

52 Publications

Bifunctional hydrogel for potential vascularized bone tissue regeneration.

Mater Sci Eng C Mater Biol Appl 2021 May 24;124:112075. Epub 2021 Mar 24.

Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, United States; Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905, United States. Electronic address:

Most of the synthetic polymer-based hydrogels lack the intrinsic properties needed for tissue engineering applications. Here, we describe a biomimetic approach to induce the mineralization and vascularization of poly(ethylene glycol) (PEG)-based hydrogel to template the osteogenic activities. The strategy involves the covalent functionalization of oligo[poly(ethylene glycol) fumarate] (OPF) with phosphate groups and subsequent treatment of phosphorylated-OPF (Pi-OPF) hydrogels with alkaline phosphatase enzyme (ALP) and calcium. Unlike previously reported studies for ALP induced mineralization, in this study, the base polymer itself was modified with the phosphate groups for uniform mineralization of hydrogels. In addition to improvement of mechanical properties, enhancement of MC3T3-E1 cell attachment and proliferation, and promotion of mesenchymal stem cells (MSC) differentiation were observed as the intrinsic benefits of such mineralization. Current bone tissue engineering (BTE) research endeavors are also extensively focused on vascular tissue regeneration due to its inherent advantages in bone regeneration. Taking this into account, we further functionalized the mineralized hydrogels with FG-4592, small hypoxia mimicking molecule. The functionalized hydrogels elicited upregulated in vitro angiogenic activities of human umbilical vein endothelial cells (HUVEC). In addition, when implanted subcutaneously in rats, enhanced early vascularization activities around the implantation site were observed as demonstrated by the immunohistochemistry results. This further leveraged the formation of calcified tissues at the implantation site at later time points evident through X-ray imaging. The overall results here show the perspectives of bifunctional OPF hydrogels for vascularized BTE.
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http://dx.doi.org/10.1016/j.msec.2021.112075DOI Listing
May 2021

HucMSC exosome-delivered 14-3-3ζ alleviates ultraviolet radiation-induced photodamage via SIRT1 pathway modulation.

Aging (Albany NY) 2021 Apr 21;13(8):11542-11563. Epub 2021 Apr 21.

Key Laboratory of Laboratory Medicine of Jiangsu Province, School of Medicine, Jiangsu University, Zhenjiang 212013, Jiangsu, People's Republic of China.

Exosomes derived from human umbilical cord mesenchymal stem cells (hucMSC-ex) are nano-sized membrane-bound vesicles that have been reported to facilitate skin regeneration and repair. However, the roles played by hucMSC-ex in ultraviolet (UV) radiation-induced skin photodamage and the underlying mechanisms remain unknown. To investigate the functions of hucMSC-ex in a rat model of acute skin photodamage, immunofluorescence and immunohistochemical staining, quantitative real-time-polymerase chain reaction (qRT-PCR), western blot, and gene silencing assays were performed. We found that the subcutaneous injection of hucMSC-ex elicited antioxidant and anti-inflammatory effects against UV radiation-induced DNA damage and apoptosis. Further studies showed that the sirtuin 1 (SIRT1) expression level in skin keratinocytes (HaCaT) decreased in a time- and dose-dependent manner under UV radiation induced-oxidative stress conditions, which could be reversed by treatment with hucMSC-ex. The activation of SIRT1 significantly attenuated UV- and HO-induced cytotoxic damage by inhibiting oxidative stress and promoting the activation of autophagy. Our study found that 14-3-3ζ protein, which was delivered by hucMSC-ex, exerted a cytoprotective function via the modulation of a SIRT1-dependent antioxidant pathway. Collectively, our findings indicated that hucMSC-ex might represent a new potential agent for preventing or treating UV radiation-induced skin photodamage and aging.
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http://dx.doi.org/10.18632/aging.202851DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8109102PMC
April 2021

3,3'-Diindolylmethane Promotes Gastric Cancer Progression β-TrCP-Mediated NF-κB Activation in Gastric Cancer-Derived MSCs.

Front Oncol 2021 24;11:603533. Epub 2021 Mar 24.

Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Institute of Stem Cell, School of Medicine, Jiangsu University, Zhenjiang, China.

Gastric cancer is a malignant tumor characterized by high morbidity and invasion. Surgery combined with chemo-radiotherapy is the most common treatment for gastric cancer, while multiple drug resistance always results in treatment failure. Once the anti-tumor drugs enter the tumor foci, tumor cells as well as those found in the microenvironment are affected. However, the effects of drugs on tumor microenvironment (TME) are easily overlooked. In this study, we investigated the effects of the anti-cancer drug 3,3'-diindolylmethane (DIM) on gastric cancer-derived mesenchymal stem cells (GC-MSCs) and their subsequent impact on cancer progression. Surprisingly, we found that the therapeutic concentration of DIM upregulated the expression level of tumor-related factors such as CCL-2, IL-6, and IL-8 in GC-MSCs. The conditioned medium of DIM-treated GC-MSCs promoted the proliferation, invasion, and migration of gastric cancer cells and tumor growth . Mechanistically, DIM enhanced the expression of β-TrCP, an E3 ubiquitin ligase leading to IκBα degradation and NF-κB activation in GC-MSCs. The β-TrCP knockdown partially eliminated positive results caused by DIM. Our results showed that the therapeutic dosage of DIM induced cell death in cancer cells, while enhancing MSC paracrine functions in the stroma to offset the original DIM effect on cancer cells. These findings provide a new mechanism of anti-cancer drug resistance and remind us to adjust the chemotherapeutic scheme by combining the anti-cancer drug with an appropriate signaling pathway inhibitor to block the side effects of drug on targeted TME cells.
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http://dx.doi.org/10.3389/fonc.2021.603533DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8024625PMC
March 2021

Exosomes derived from autologous dermal fibroblasts promote diabetic cutaneous wound healing through the Akt/β-catenin pathway.

Cell Cycle 2021 Mar-Mar;20(5-6):616-629. Epub 2021 Mar 8.

Jiangsu Key Laboratory of Medical Science and Laboratory Medicine, Institute of Stem Cell, School of Medicine, Jiangsu University, Zhenjiang, Jiangsu, China.

Diabetic cutaneous wounds are one of the complications of diabetes mellitus (DM) and are difficult to cure at present. Autologous dermal fibroblasts (DFs) have shown great promise in skin regeneration and repair. However, whether exosomes derived from autologous dermal fibroblasts (DF-Ex) can be used to accelerate diabetic cutaneous wound healing is unclear. In this study, human umbilical vein endothelial cells (HUVECs) were treated with high glucose. We found that DF-Ex could reverse the damage produced by high glucose in HUVECs in vitro. A high-fat diet and streptozotocin were used to establish a rat model of type 2 diabetes mellitus (T2DM), and a diabetic cutaneous wound model was established in the T2DM rats. We discovered that subcutaneous injections of DF-Ex could significantly promote re-epithelialization, collagen deposition, skin cell proliferation, angiogenesis and inhibit inflammation to accelerate diabetic cutaneous wound healing. We further explored the underlying mechanism and found that DF-Ex exerted positive effects by activating the Akt/β-catenin pathway. This research revealed that DF-Ex may provide a new treatment strategy for diabetic cutaneous wound healing.
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http://dx.doi.org/10.1080/15384101.2021.1894813DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8018430PMC
March 2021

Discovery of 3,6-disubstutited-imidazo[1,2-a]pyridine derivatives as a new class of CLK1 inhibitors.

Bioorg Med Chem Lett 2021 Jun 2;41:127881. Epub 2021 Mar 2.

Key Laboratory of Drug Targeting and Drug Delivery System of Ministry of Education, West China School of Pharmacy, Sichuan University, Sichuan 610041, China. Electronic address:

Inhibition of cdc2-like kinase1 (CLK1) could efficiently induce autophagy and it has been thought as a potential target for treatment of autophagy-related diseases. Herein we report the discovery of a series of 3,6-disubstutited-imidazo[1,2-a]pyridine derivatives as a new class of CLK1 inhibitors. Among them, compound 9e is the most potent one, which exhibits an IC value of 4 nM against CLK1 kinase. In vitro, this compound reduces the phosphorylation level of the typical downstream substrates of CLK1 and affects their subcellular redistribution. Further study indicates that 9e is efficient to induce autophagy. Overall, this study provides a promising lead compound for drug discovery targeting CLK1 kinase.
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http://dx.doi.org/10.1016/j.bmcl.2021.127881DOI Listing
June 2021

SARS-CoV-2 M inhibitors with antiviral activity in a transgenic mouse model.

Science 2021 03 18;371(6536):1374-1378. Epub 2021 Feb 18.

State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China.

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continually poses serious threats to global public health. The main protease (M) of SARS-CoV-2 plays a central role in viral replication. We designed and synthesized 32 new bicycloproline-containing M inhibitors derived from either boceprevir or telaprevir, both of which are approved antivirals. All compounds inhibited SARS-CoV-2 M activity in vitro, with 50% inhibitory concentration values ranging from 7.6 to 748.5 nM. The cocrystal structure of M in complex with MI-23, one of the most potent compounds, revealed its interaction mode. Two compounds (MI-09 and MI-30) showed excellent antiviral activity in cell-based assays. In a transgenic mouse model of SARS-CoV-2 infection, oral or intraperitoneal treatment with MI-09 or MI-30 significantly reduced lung viral loads and lung lesions. Both also displayed good pharmacokinetic properties and safety in rats.
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http://dx.doi.org/10.1126/science.abf1611DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8099175PMC
March 2021

Mesenchymal stem cell spheroids incorporated with collagen and black phosphorus promote osteogenesis of biodegradable hydrogels.

Mater Sci Eng C Mater Biol Appl 2021 Feb 28;121:111812. Epub 2020 Dec 28.

Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA; Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905, USA. Electronic address:

Mesenchymal stem cell (MSC)-spheroids have sparked significant interest in bone tissue engineering due to their resemblance to natural bone tissue, especially in terms of cell-cell and cell-extracellular matrix interactions. Many biomaterials or biomolecules have been incorporated into MSC-spheroids to enhance their osteogenic abilities. In this respect, we assessed the osteogenic responses of MSC spheroids leveraged through the unique combination of collagen and black phosphorus (BP). The MSC spheroids were successfully constructed with 6 μg/mL collagen and/or a concentration gradient (0 μg/mL, 4 μg/mL, 8 μg/mL, and 16 μg/mL) of BP and were evaluated for MSC viability and their osteogenic differentiation over a time period of 14 days. Improved MSC viability and osteogenic ability were observed for the spheroids with collagen and BP at the concentration of 4 μg/mL and 8 μg/mL. Next, blank spheroids (Control) or the optimized MSC spheroids with 6 μg/mL collagen and 4 μg/mL BP (Col+BP4) were further encapsulated into two types of hydrogel scaffolds: porous oligo[poly(ethylene glycol) fumarate] (OPF) hydrogel and hydroxyapatite-collagen I scaffold (HE-COL). The osteogenic abilities of these four groups were evaluated after 14 and 21 days of osteogenic induction. The MSC spheroids incorporated with collagen and BP implanted into OPF porous hydrogel (Col+BP/OPF) elicited a higher expression of Runx2, osteopontin, and alkaline phosphatase than blank spheroids implanted into OPF porous hydrogel (Control/OPF). Enhanced osteogenesis was also observed in the Col+BP/HE-COL group as compared to Control/HE-COL. Taken together, the results from this study showed the perspectives of collagen and BP incorporated MSC spheroids for the development of injectable cellular therapies for bone regeneration.
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http://dx.doi.org/10.1016/j.msec.2020.111812DOI Listing
February 2021

Discovery of selective BPTF bromodomain inhibitors by screening and structure-based optimization.

Biochem Biophys Res Commun 2021 03 3;545:125-131. Epub 2021 Feb 3.

Key Laboratory of Drug Targeting and Drug Delivery System of Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan, 610041, People's Republic of China. Electronic address:

Bromodomain and PHD finger containing transcription factor (BPTF) is a multidomain protein that regulates the transcription of chromatin and is related to many cancers. Herein, we report the screening-based discovery of Cpd1, a compound with micromolar affinity to the BPTF bromodomain. Through structure-guided optimization, we synthesized a variety of new inhibitors. Among these compounds, Cpd8 and Cpd10 were highly potent and selective inhibitors, with K values of 428 nM and 655 nM in ITC assays, respectively. The high activity was explained by the cocrystal structure of Cpd8 in complex with the BPTF bromodomain protein. Cpd8 and Cpd10 were able to stabilize the BPTF bromodomain protein in cells in a cellular thermal shift assay (CETSA). Cpd8 downregulated c-MYC expression in A549 cells. All experiments prove that these two compounds are potential BPTF inhibitors.
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http://dx.doi.org/10.1016/j.bbrc.2021.01.067DOI Listing
March 2021

Injectable Electrical Conductive and Phosphate Releasing Gel with Two-Dimensional Black Phosphorus and Carbon Nanotubes for Bone Tissue Engineering.

ACS Biomater Sci Eng 2020 08 9;6(8):4653-4665. Epub 2020 Jul 9.

Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota 55905, United States.

Injectable hydrogels have unique advantages for the repair of irregular tissue defects. In this study, we report a novel injectable carbon nanotube (CNT) and black phosphorus (BP) gel with enhanced mechanical strength, electrical conductivity, and continuous phosphate ion release for tissue engineering. The gel utilized biodegradable oligo(poly(ethylene glycol) fumarate) (OPF) polymer as the cross-linking matrix, with the addition of cross-linkable CNT-poly(ethylene glycol)-acrylate (CNTpega) to grant mechanical support and electric conductivity. Two-dimensional (2D) black phosphorus nanosheets were also infused to aid in tissue regeneration through the steady release of phosphate that results from environmental oxidation of phosphorus in situ. This newly developed BP-CNTpega-gel was found to enhance the adhesion, proliferation, and osteogenic differentiation of MC3T3 preosteoblast cells. With electric stimulation, the osteogenesis of preosteoblast cells was further enhanced with elevated expression of several key osteogenic pathway genes. As monitored with X-ray imaging, the BP-CNTpega-gel demonstrated excellent in situ gelation and cross-linking to fill femur defects, vertebral body cavities, and posterolateral spinal fusion sites in the rabbit. Together, these results indicate that this newly developed injectable BP-CNTpega-gel owns promising potential for future bone and broad types of tissue engineering applications.
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http://dx.doi.org/10.1021/acsbiomaterials.0c00612DOI Listing
August 2020

Structure-activity relationship studies of phenothiazine derivatives as a new class of ferroptosis inhibitors together with the therapeutic effect in an ischemic stroke model.

Eur J Med Chem 2021 Jan 18;209:112842. Epub 2020 Sep 18.

State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China. Electronic address:

Ferroptosis is a new type of programmed cell death discovered recently and has been demonstrated to be involved in a number of human diseases such as ischemic stroke. Ferroptosis inhibitors are expected to have potential to treat these diseases. Herein, we report the identification of promethazine derivatives as a new type of ferroptosis inhibitors. Structure-activity relationship (SAR) analyses led to the discovery of the most potent compound 2-(1-(4-(4-methylpiperazin-1-yl)phenyl)ethyl)-10H-phenothiazine (51), which showed an EC (half maximal effective concentration) value of 0.0005 μM in the erastin-induced HT1080 cell ferroptosis model. In the MCAO (middle cerebral artery occlusion) ischemic stroke model, 51 presented an excellent therapeutic effect. This compound also displayed favorable pharmacokinetic properties, in particular, a good ability to permeate the blood-brain barrier. Overall, 51 could be a promising lead compound for the treatment of ferroptosis related diseases and deserves further investigations.
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http://dx.doi.org/10.1016/j.ejmech.2020.112842DOI Listing
January 2021

Discovery of small molecule FLT3 inhibitors that are able to overcome drug-resistant mutations.

Bioorg Med Chem Lett 2020 11 3;30(22):127532. Epub 2020 Sep 3.

Key Laboratory of Drug Targeting and Drug Delivery System of Ministry of Education, West China School of Pharmacy, Sichuan University, Sichuan 610041, China. Electronic address:

Herein we report the discovery of 1-(5-(tert-butyl)isoxazol-3-yl)-3- (3-fluorophenyl)urea derivatives as new FLT3 inhibitors that are able to overcome the drug resistance mutations: the secondary D835Y and F691L mutations on the basis of the internal tandem duplications (ITD) mutation of FLT3 (FLT3-ITD/D835Y and FLT3-ITD/F691L, respectively). The most potent compound corresponds to 1-(5-(tert-butyl)isoxazol-3-yl)-3-(4-((6,7-dimethoxyquinolin-4-yl)oxy)-3- fluorophenyl)urea (4d), which showed ICs (half maximal inhibitory concentrations) of 0.072 nM, 5.86 nM and 3.48 nM against FLT3-ITD, FLT3-ITD/F691L and FLT3-ITD/D835Y, respectively. Compound 4d also showed good selectivity for FLT3 in a kinase profiling assay. Collectively, 4d could be a good lead compound and deserves further in-depth studies.
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http://dx.doi.org/10.1016/j.bmcl.2020.127532DOI Listing
November 2020

Discovery and structure-activity relationship studies of 1-aryl-1H-naphtho[2,3-d][1,2,3]triazole-4,9-dione derivatives as potent dual inhibitors of indoleamine 2,3-dioxygenase 1 (IDO1) and trytophan 2,3-dioxygenase (TDO).

Eur J Med Chem 2020 Dec 14;207:112703. Epub 2020 Aug 14.

State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan, 610041, China. Electronic address:

Indoleamine 2,3-dioxygenase 1 (IDO1) and tryptophan 2,3-dioxygenase (TDO), which mediate kynurenine pathway of tryptophan degradation, have emerged as potential new targets in immunotherapy for treatment of cancer because of their critical role in immunosuppression in the tumor microenvironment. In this investigation, we report the structural optimization and structure-activity relationship studies of 1-phenyl-1H-naphtho[2,3-d][1,2,3]triazole-4,9-dione derivatives as a new class of IDO1/TDO dual inhibitors. Among all the obtained dual inhibitors, 1-(3-chloro-4-fluorophenyl)-6-fluoro-1H-naphtho[2,3-d][1,2,3]triazole-4,9-dione (38) displayed the most potent IDO1 and TDO inhibitory activities with IC (half-maximal inhibitory concentration) values of 5 nM for IDO1 and 4 nM for TDO. It turned out that compound 38 was not a PAINS compound. Compound 38 could efficiently inhibit the biofunction of IDO1 and TDO in intact cells. In LL2 (Lewis lung cancer) and Hepa1-6 (hepatic carcinoma) allograft mouse models, this compound also showed considerable in vivo anti-tumor activity and no obvious toxicity was observed. Therefore, 38 could be a good lead compound for cancer immunotherapy and deserving further investigation.
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http://dx.doi.org/10.1016/j.ejmech.2020.112703DOI Listing
December 2020

Discovery of Potent Small-Molecule SIRT6 Activators: Structure-Activity Relationship and Anti-Pancreatic Ductal Adenocarcinoma Activity.

J Med Chem 2020 09 9;63(18):10474-10495. Epub 2020 Sep 9.

State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, P. R. China.

SIRT6 activation is thought to be a promising target for the treatment of many diseases, particularly cancer. Herein, we report the discovery of a series of new small-molecule SIRT6 activators. Structure-activity relationship analyses led to the identification of the most potent compound, 2-(1-benzofuran-2-yl)--(diphenylmethyl) quinoline-4-carboxamide (), which showed an EC value of 0.58 ± 0.12 μM and an EC value of 5.35 ± 0.69 μM against SIRT6-dependent peptide deacetylation in FLUOR DE LYS assay. It exhibited weak or no activity against other HDAC family members as well as 415 kinases, indicating good selectivity for SIRT6. significantly inhibited the proliferation and migration of pancreatic ductal adenocarcinoma (PDAC) cells . It also markedly suppressed the tumor growth in a PDAC tumor xenograft model. This compound showed attractive pharmacokinetic properties. Overall, could be a good lead compound for the treatment of PDAC, and it is worthy of further study.
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http://dx.doi.org/10.1021/acs.jmedchem.0c01183DOI Listing
September 2020

Cerebrospinal Fluid Pulsation Stress Promotes the Angiogenesis of Tissue-Engineered Laminae.

Stem Cells Int 2020 2;2020:8026362. Epub 2020 Jul 2.

Department of Orthopedics, Shanghai Fifth People's Hospital, Fudan University, China.

Background: Angiogenesis is a prerequisite step to achieve the success of bone regeneration by tissue engineering technology. Previous studies have shown the role of cerebrospinal fluid pulsation (CSFP) stress in the reconstruction of tissue-engineered laminae. In this study, we investigated the role of CSFP stress in the angiogenesis of tissue-engineered laminae.

Methods: For the study, a CSFP bioreactor was used to investigate the impact of CSFP stress on the osteogenic mesenchymal stem cells (MSCs). For the study, forty-eight New Zealand rabbits were randomly divided into the CSFP group and the Non-CSFP group. Tissue-engineered laminae (TEL) was made by hydroxyapatite-collagen I scaffold and osteogenic MSCs and then implanted into the lamina defect in the two groups. The angiogenic and osteogenic abilities of newborn laminae were examined with histological staining, qRT-PCR, and radiological analysis.

Results: The study showed that CSFP stress could promote the vascular endothelial growth factor A (VEGF-A) expression levels of osteogenic MSCs. In the animal study, the expression levels of angiogenic markers in the CSFP group were higher than those in the Non-CSFP group; moreover, in the CSFP group, their expression levels on the dura mater surface, which are closer to the CSFP stress stimulation, were also higher than those on the paraspinal muscle surface. The expression levels of osteogenic markers in the CSFP group were also higher than those in the Non-CSFP group.

Conclusion: CSFP stress could promote the angiogenic ability of osteogenic MSCs and thus promote the angiogenesis of tissue-engineered laminae. The pretreatment of osteogenic MSC with a CSFP bioreactor may have important implications for vertebral lamina reconstruction with a tissue engineering technique.
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http://dx.doi.org/10.1155/2020/8026362DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7352145PMC
July 2020

Discovery of 5-(4-methylpiperazin-1-yl)-2-nitroaniline derivatives as a new class of SIRT6 inhibitors.

Bioorg Med Chem Lett 2020 08 25;30(16):127215. Epub 2020 Apr 25.

Key Laboratory of Drug Targeting and Drug Delivery System of Ministry of Education, West China School of Pharmacy, Sichuan University, Chengdu, Sichuan 610041, PR China. Electronic address:

SIRT6 is a deacetylase of histone H3 and inhibitors of SIRT6 have been thought as potential agents for treatment of diabetes. Herein we report the discovery of a series of new SIRT6 inhibitors containing the skeleton 1-phenylpiperazine. Among them, compound 5-(4-methylpiperazin-1-yl)-2-nitroaniline (6d) is the most potent one, which showed an IC value of 4.93 μM against SIRT6 in the Fluor de Lys (FDL) assay. It displayed K values of 9.76 μM and 10 μM in surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) assays, respectively. In selectivity assay, 6d showed no activity against other members of the HDAC family (SIRT1-3 and HDAC1-11) at concentrations up to 200 µM. In a mouse model of type 2 diabetes, 6d could significantly increase the level of glucose transporter GLUT-1, thereby reducing blood glucose. Overall, this study provides a promising lead compound for subsequent drug discovery targeting SIRT6.
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http://dx.doi.org/10.1016/j.bmcl.2020.127215DOI Listing
August 2020

Cervinomycins C with cytotoxic and antibacterial activity from Streptomyces sp. CPCC 204980.

J Antibiot (Tokyo) 2020 12 3;73(12):812-817. Epub 2020 Jul 3.

NHC Key Laboratory of Biotechnology of Antibiotics, CAMS Key Laboratory of Synthetic Biology for Drug Innovation, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China.

Polycyclic xanthones are secondary metabolites from actinomycetes and cervinomycin A and B are bioactive 26-membered polycyclic xanthones from Streptomyces sp. CPCC 204980. Herein, we report cervinomycins C (1-4) from the same strain. The structures of 1-4 were determined by 1D- and 2D-NMR, or single-crystal X-ray diffraction. Compounds 1-4 feature the open or loss of A (oxazolidine) ring in their angular polycyclic framework compared with cervinomycin B. Compounds 1-4 showed potent cytotoxicity against human cancer cell lines HCT116 and BxPC-3, with IC at 0.9-801.0 nM and strong anti-Gram-positive bacterial activity.
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http://dx.doi.org/10.1038/s41429-020-0342-1DOI Listing
December 2020

3D-printed scaffolds with carbon nanotubes for bone tissue engineering: Fast and homogeneous one-step functionalization.

Acta Biomater 2020 07 16;111:129-140. Epub 2020 May 16.

Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA; Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN 55905, USA. Electronic address:

Three-dimensional (3D) printing is a promising technology for tissue engineering. However, 3D-printing methods are limited in their ability to produce desired microscale features or electrochemical properties in support of robust cell adhesion, proliferation, and differentiation. This study addresses this deficiency by proposing an integrated, one-step, method to increase the cytocompatibility of 3D-printed scaffolds through functionalization leveraging conductive carbon nanotubes (CNTs). To this end, CNTs were first sonicated with water-soluble single-stranded deoxyribonucleic acid (ssDNA) to generate a negatively charged ssDNA@CNT nano-complex. Concomitantly, 3D-printed poly(propylene fumarate) (PPF) scaffolds were ammonolyzed to introduce free amine groups, which can take on a positive surface charge in water. The ssDNA@CNT nano-complex was then applied to 3D-printed scaffolds through a simple one-step coating utilizing electric-static force. This fast and facile functionalization step resulted in a homogenous and non-toxic coating of CNTs to the surface, which significantly improved the adhesion, proliferation, and differentiation of pre-osteoblast cells. In addition, the CNT based conductive coating layer enabled modulation of cell behavior through electrical stimuli (ES) leading to cellular proliferation and osteogenic gene marker expression, including alkaline phosphatase (ALP), osteocalcin (OCN), and osteopontin (OPN). Collectively, these data provide the foundation for a one-step functionalization method for simple, fast, and effective functionalization of 3D printed scaffolds that support enhanced cell adhesion, proliferation, and differentiation, especially when employed in conjunction with ES. STATEMENT OF SIGNIFICANCE: Three-dimensional (3D) printing is a promising technology for tissue engineering. However, 3D-printing methods have limited ability to produce desired features or electrochemical properties in support of robust cell behavior. To address this deficiency, the current study proposed an integrated, one-step method to increase the cytocompatibility of 3D-printed scaffolds through functionalization leveraging conductive carbon nanotubes (CNTs). This fast and facile functionalization resulted in a homogenous and non-toxic coating of CNTs to the surface, which significantly improved the adhesion, proliferation, and differentiation of cells on the 3D-printed scaffolds.
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http://dx.doi.org/10.1016/j.actbio.2020.04.047DOI Listing
July 2020

1-hydroxy-7-oxolavanducyanin and Δ-6″-hydroxynaphthomevalin from Streptomyces sp. CPCC 203577.

J Antibiot (Tokyo) 2020 05 12;73(5):324-328. Epub 2020 Feb 12.

NHC Key Laboratory of Biotechnology of Antibiotics, CAMS Key Laboratory of Synthetic Biology for Drug Innovation, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, PR China.

Lavanducyanin is a bioactive phenazine-containing secondary metabolite, and naphthomevalin is an antibacterial polyketide secondary metabolite. Herein, new analogues of lavanducyanin (2) and of naphthomevalin (4), together with lavanducyanin (1) and naphthomevalin (3), were identified from Streptomyces sp. CPCC 203577, an actinomycete soil isolate. The structures of 2 and 4 were elucidated as 1-hydroxy-7-oxolavanducyanin and Δ-6″-hydroxynaphthomevalin, respectively, by 1D and 2D NMR. Antibacterial assays revealed that 2 had significant but reduced anti-Gram-positive bacterial activity compared with 1, and 4 was devoid of anti-Gram-positive bacterial activity. This indicated that the phenazinone nucleus in lavanducyanin and the monoterpene side chain in naphthomevalin might be important for their anti-Gram-positive bacterial activity. Compounds 1-4 were all inactive against Gram-negative bacteria.
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http://dx.doi.org/10.1038/s41429-020-0282-9DOI Listing
May 2020

Comparison of Baumgaertner and Chang reduction quality criteria for the assessment of trochanteric fractures.

Bone Joint Res 2019 Oct 2;8(10):502-508. Epub 2019 Nov 2.

Department of Orthopaedics, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China.

Objectives: Different criteria for assessing the reduction quality of trochanteric fractures have been reported. The Baumgaertner reduction quality criteria (BRQC) are relatively common and the Chang reduction quality criteria (CRQC) are relatively new. The objectives of the current study were to compare the reliability of the BRQC and CRQC in predicting mechanical complications and to investigate the clinical implications of the CRQC.

Methods: A total of 168 patients were assessed in a retrospective observational study. Clinical information including age, sex, fracture side, American Society of Anesthesiologists (ASA) classification, tip-apex distance (TAD), fracture classification, reduction quality, blade position, BRQC, CRQC, bone quality, and the occurrence of mechanical complications were used in the statistical analysis.

Results: A total of 127 patients were included in the full analysis, and mechanical complications were observed in 26 patients. The TAD, blade position, BRQC and CRQC were significantly associated with mechanical complications in the univariate analysis. Only the TAD (p = 0.025) and the CRQC (p < 0.001) showed significant results in the multivariate analysis. In the comparison of the receiver operating characteristic curves, the CRQC also performed better than the BRQC.

Conclusion: The CRQC are reliable in predicting mechanical complications and are more reliable than the BRQC. Future studies could use the CRQC to assess fracture reduction quality. Intraoperatively, the surgeon should refer to the CRQC to achieve good reduction in trochanteric fractures.: 2019;8:502-508.
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http://dx.doi.org/10.1302/2046-3758.810.BJR-2019-0032.R1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6825041PMC
October 2019

Discovery of 4-Chromen-4-one Derivatives as a New Class of Selective Rho Kinase (ROCK) Inhibitors, which Showed Potent Activity in ex Vivo Diabetic Retinopathy Models.

J Med Chem 2019 12 20;62(23):10691-10710. Epub 2019 Nov 20.

Diabetic retinopathy (DR) is a major cause of blindness, and there is a lack of effective treatment at present. Rho-associated coiled-coil containing serine/threonine protein kinases (ROCKs) have recently been suggested as potential targets for the DR treatment. We herein report the discovery of 4-chromen-4-one derivatives as a new class of ROCK inhibitors. Structure-activity relationship analyses led to the identification of the most active compound, 4-(dimethylamino)--(3-{2-[(4-oxo-4-chromen-7-yl)oxy]acetamido}phenyl) (). This compound showed excellent kinase selectivity for ROCK I and ROCK II against 387 other kinases. In retinal explants, compound protected retinal neurons from high glucose-induced oxidative stress and apoptosis-mediated cell death. Furthermore, administration suppressed the improper proliferation of Müller cells and promoted the regression of vascular vessels in retinal explants cultured in a high glucose microenvironment. Collectively, our data suggest that could be a potential lead compound for the treatment of DR, hence deserving further in-depth studies.
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http://dx.doi.org/10.1021/acs.jmedchem.9b01143DOI Listing
December 2019

Discovery of 1,8-disubstituted-[1,2,3]triazolo[4,5-c]quinoline derivatives as a new class of Hippo signaling pathway inhibitors.

Bioorg Med Chem Lett 2019 09 2;29(18):2595-2603. Epub 2019 Aug 2.

State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China. Electronic address:

Inhibitors of the Hippo signaling pathway have been demonstrated to have a potential clinical application in cases such as tissue repair and organ regeneration. However, there is a lack of potent Hippo pathway inhibitors at present. Herein we report the discovery of a series of 1,8-disubstituted-[1,2,3]triazolo[4,5-c]quinoline derivatives as a new class of Hippo pathway inhibitors by utilizing a cell line-based screening model (A549-CTGF). Structure-activity relationship (SAR) of these compounds was also discussed. The most potent compound in the A549-CTGF cell assay, 11g, was then evaluated by real-time PCR and immunofluorescence assays. Overall, this study provides a starting point for later drug discovery targeting the Hippo signaling pathway.
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http://dx.doi.org/10.1016/j.bmcl.2019.08.001DOI Listing
September 2019

Cytotoxic and Antibacterial Cervinomycins B from a Species.

J Nat Prod 2019 08 5;82(8):2337-2342. Epub 2019 Aug 5.

NHC Key Laboratory of Biotechnology of Antibiotics, CAMS Key Laboratory of Synthetic Biology for Drug Innovation , Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College , Beijing 100050 , People's Republic of China.

AntiSMASH analysis of genome DNA of CPCC 204980, a soil isolate with potent antibacterial activity, revealed a gene cluster for polycyclic xanthones. A subsequent chemical study confirmed that the microorganism produced polycyclic xanthone cervinomycin A () and the new congeners cervinomycins B (-). The structures of - were determined by comprehensive analyses of MS and NMR data, which indicated that - featured a common dihydro-D ring in the polycyclic xanthone core moiety of their molecules. - are toxic to human cancer cells and active against Gram-positive bacteria.
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http://dx.doi.org/10.1021/acs.jnatprod.9b00198DOI Listing
August 2019

Exosomal MMP2 derived from mature osteoblasts promotes angiogenesis of endothelial cells via VEGF/Erk1/2 signaling pathway.

Exp Cell Res 2019 10 29;383(2):111541. Epub 2019 Jul 29.

Department of Orthopedics, The Fifth People's Hospital of Shanghai, Fudan University, China; Department of Orthopedics, Huashan Hospital, Fudan University, China. Electronic address:

The skeletal system is a dynamic organ that continuously undergoes coupled trabeculae and blood vessels remodeling, indicating the possible existence of molecular crosstalk between endothelial and osteoblastic cells. Since the cross-talk between bone-forming osteoblasts (OBs) and vessel-forming endothelial cells (ECs) have progressively gained investigators' attention, few studies focused on the regulatory function of extracellular vesicles derived from OBs on ECs. In this study, the effect of the exosomes derived from mature osteoblasts (MOBs) on the ECs was investigated. Firstly, exosomes derived from mature osteoblasts (MOB-Exos) were isolated and identified by NanoSight light scatter technology, electron microscopy and Western bolting. Fluorescent labeling of MOB-Exos revealed its internalization by ECs. RNA interference technique was used to knock down matrix metalloproteinase-2 (MMP2) in MOB-Exos. Then ECs were co-cultured with MOB-Exos and MMP2 knockdown MOB-Exos. Wound healing migration assay, transwell migration assay, CCK-8 assay and tube formation assay of ECs were conducted to determine the angiogenic capability of ECs. Then the VEGF/Erk1/2 pathway markers were detected by Western blot. Our results showed that MOB-Exos could promote the proliferation, migration and tube formation of ECs. Meanwhile, the promoted angiogenetic capacities of ECs were impaired when MMP2 in MOB-Exos was knocked down. In addition, immunoblotting indicated that MOB-Exos could promote the activation of the VEGF/Erk1/2 pathway of ECs; whereas the activation of the VEGF/Erk1/2 pathway was attenuated when the ECs were co-cultured with the MMP2 knockdown MOB-Exos. In conclusion, the MMP-2 existing in exosomes derived from MOBs could promote the angiogenesis of ECs in vitro, which might be realized through VEGF/Erk1/2 signaling pathway.
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http://dx.doi.org/10.1016/j.yexcr.2019.111541DOI Listing
October 2019

Genome-Guided Discovery of Pretilactam from ATCC 31565.

Molecules 2019 Jun 19;24(12). Epub 2019 Jun 19.

NHC Key Laboratory of Biotechnology of Antibiotics, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.

is a small but well-known genus of actinomycetes for production of ansamitocin, the payload component of antibody-drug conjugates against cancers. However, the secondary metabolite production profile of ATCC 31565, the most famous producer of ansamitocin, has never been fully explored. Our antiSMASH analysis of the genomic DNA of ATCC 31565 revealed a NRPS-PKS gene cluster for polyene macrolactam. The gene cluster is very similar to gene clusters for mirilactam and salinilactam, two 26-membered polyene macrolactams from and , respectively. Guided by this bioinformatics prediction, we characterized a novel 26-membered polyene macrolactam from ATCC 31565 and designated it pretilactam. The structure of pretilactam was elucidated by a comprehensive analysis of HRMS, 1D and 2D-NMR, with absolute configuration of chiral carbons predicted bioinformatically. Pretilactam features a dihydroxy tetrahydropyran moiety, and has a hexaene unit and a diene unit as its polyene system. A preliminary antibacterial assay indicated that pretilactam is inactive against and .
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http://dx.doi.org/10.3390/molecules24122281DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6631532PMC
June 2019

Comparative analysis of mesenchymal stromal cells derived from rabbit bone marrow and Wharton's jelly for adipose tissue engineering.

Connect Tissue Res 2020 11 18;61(6):537-545. Epub 2019 Jun 18.

Department of Orthopedics, The Fifth People's Hospital of Shanghai, Fudan University , Shanghai, China.

: To investigate the proliferative, adipogenic, and immunological properties of rabbit Mesenchymal stromal cells (MSCs) derived from bone marrow and umbilical cord Wharton's jelly.: We extracted rabbit MSCs from bone marrow (BMSCs) and umbilical cord Wharton's jelly (WJ-MSCs). Both BMSCs and WJ-MSCs underwent adipogenic differentiation for 2 weeks, and then were transferred to non-inductive complete medium. Their adipogenic capacities were examined by histomorphometry and quantitative RT-PCR (qRT-PCR). The immunological markers were determined by mRNA expression of MHC-Ia, MHC-II, and RLA-DRA by qRT-PCR and protein expression of MHC-II by immunofluorescent staining. The proliferative capacities of adipogenic MSCs were also examined by counting kit-8 experiment and cell population doubling time.: We found that adipogenic differentiation increased the mRNA expression levels of adipogenic and immunological markers. The protein expression levels of MHC-II also increased after adipogenic differentiation in both groups. The adipogenic BMSCs showed higher mRNA expression levels of adipogenic and immunological markers. Removal of adipogenic agents after 2 weeks of adipo-differentiation inversely decreased the expression of immunological and adipogenic markers. The adipo-differentiation could decreased the proliferative capacities of both MSCs, but the adipogenic WJ-MSCs showed significantly higher proliferative capacities than BMSCs.: Adipogenic differentiation increased the immunogenicity of both BMSCs and WJ-MSCs, and dedifferentiation inversely decreased their immunogenicity. Adipogenic WJ-MSCs showed significantly higher proliferative and immunoprivileged capacities than BMSCs, and the dedifferentiated BMSCs showed almost the same adipogenic capacity as WJ-MSCs. WJ-MSCs were more suitable than BMSCs for adipose tissue engineering.
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http://dx.doi.org/10.1080/03008207.2019.1631297DOI Listing
November 2020

Isarubrolones Containing a Pyridooxazinium Unit from Streptomyces as Autophagy Activators.

J Nat Prod 2019 05 9;82(5):1149-1154. Epub 2019 May 9.

NHC Key Laboratory of Biotechnology of Antibiotics, Key Laboratory of Synthetic Biology for Drug Innovation, Institute of Medicinal Biotechnology , Chinese Academy of Medical Sciences and Peking Union Medical College , Beijing 100050 , People's Republic of China.

Isarubrolones are bioactive polycyclic tropoloalkaloids from Streptomyces. Three new isarubrolones (2-4), together with the known isarubrolone C (1) and isatropolones A (5) and C (6, 3( R)-hydroxyisatropolone A), were identified from Streptomyces sp. CPCC 204095. The structures of these compounds were determined using a combination of mass spectrometry, 1D and 2D NMR spectroscopy, and ECD. Compounds 3 and 4 feature a pyridooxazinium unit, which is rarely seen in natural products. Compound 6 could conjugate with amino acids or amines to expand the structural diversity of isarubrolones with a pentacyclic or hexacyclic core. Importantly, 1 and 3-6 were found to induce complete autophagy.
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http://dx.doi.org/10.1021/acs.jnatprod.8b00857DOI Listing
May 2019

Discovery of 5-(5-fluoro-1H-pyrrolo[2,3-b]pyridin-3-yl)pyrazin-2(1H)-one derivatives as new potent PB2 inhibitors.

Bioorg Med Chem Lett 2019 07 26;29(13):1609-1613. Epub 2019 Apr 26.

Key Laboratory of Drug Targeting and Drug Delivery System of Ministry of Education, West China School of Pharmacy, Sichuan University, Sichuan 610041, China. Electronic address:

PB2 is an important subunit of influenza RNA-dependent RNA polymerase (RdRP) and has been recognized as a promising target for the treatment of influenza. We herein report the discovery of a new series of PB2 inhibitors containing the skeleton 5-(5-fluoro-1H-pyrrolo[2,3-b]pyridin-3-yl)pyrazin-2(1H)-one. Compound 12b is the most potent one, which showed K values of 0.11 μM and 0.19 μM in surface plasmon resonance (SPR) and isothermal titration calorimetry (ITC) assays, respectively. In antiviral activity and cellular cytotoxicity assays, compound 12b showed an EC value of 1.025 μM and a CC value greater than 100 μM. Molecular docking was also used to predict the binding mode of 12b with PB2. Collectively, this study provides a promising lead compound for subsequent anti-influenza drug discovery targeting PB2.
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http://dx.doi.org/10.1016/j.bmcl.2019.04.042DOI Listing
July 2019

Discovery of Pyrrolo[3,2- d]pyrimidin-4-one Derivatives as a New Class of Potent and Cell-Active Inhibitors of P300/CBP-Associated Factor Bromodomain.

J Med Chem 2019 05 30;62(9):4526-4542. Epub 2019 Apr 30.

State Key Laboratory of Biotherapy and Cancer Center, West China Hospital , Sichuan University , Chengdu 610041 , P. R. China.

Herein, we report the discovery of a series of new P300/CBP-associated factor (PCAF) bromodomain (BRD) inhibitors, which were obtained through a hit discovery process and subsequent structure-based optimization and structure-activity relationship analyses toward a retrieved hit compound (12). Among these inhibitors, ( R, R)-36n is the most potent one with an IC of 7 nM in homogeneous time-resolved fluorescence assay and a K of 78 nM in isothermal titration calorimetry assay. This compound also exhibited activity against GCN5 and FALZ, but weak or no activity against other 29 BRD proteins and 422 kinases, indicating considerable selectivity. X-ray cocrystal structure analysis revealed the molecular interaction mode and the precise stereochemistry required for bioactivity. Cellular activity, preliminary RNA-seq analysis, and pharmacokinetic properties were also examined for this compound. Collectively, this study provides a versatile tool molecule to explore molecular mechanisms of PCAF BRD regulation and also offers a new lead compound for drug discovery targeting PCAF.
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http://dx.doi.org/10.1021/acs.jmedchem.9b00096DOI Listing
May 2019

The bromodomain protein BRD4 positively regulates necroptosis via modulating MLKL expression.

Cell Death Differ 2019 Oct 15;26(10):1929-1941. Epub 2019 Jan 15.

State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, 610041, China.

Necroptosis is a programmed form of necrotic cell death, which is tightly regulated by the necroptotic signaling pathway containing receptor-interacting protein (RIP)1, RIP3, and mixed-lineage kinase domain-like (MLKL) protein. In addition to the RIP1-RIP3-MLKL axis, other factors regulating necroptosis are still largely unknown. Here a cell-based small-molecule screening led to the finding that BET inhibitors protected cells from necroptosis in the TNFα/Smac-mimetic/Z-VAD-FMK (TSZ)-induced cell necroptosis model. Mechanistic studies revealed that BET inhibitors acted by downregulating MLKL expression. Further research demonstrated that BRD4, IRF1, P-TEFb, and RNA polymerase II formed a transcription complex to regulate the expression of MLKL, and BET inhibitors interfered with the transcription complex formation. In necroptosis-related disease model, the BET inhibitor JQ-1 showed promising therapeutic effects. Collectively, our studies establish, for the first time, BRD4 as a new epigenetic factor regulating necroptosis, and highlight the potential of BET inhibitors in the treatment of necroptosis-related diseases.
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http://dx.doi.org/10.1038/s41418-018-0262-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6748082PMC
October 2019