Mouse islet-derived stellate cells are similar to, but distinct from, mesenchymal stromal cells and influence the beta cell function.

AIMS: Evidence is accumulating of the therapeutic benefits of mesenchymal stromal cells (MSCs) in diabetes-related conditions. We have identified a novel population of stromal cells within islets of Langerhans - islet stellate cells (ISCs) - which have a similar morphology to MSCs. In this study we characterize mouse ISCs and compare their morphology and function to MSCs to determine whether ISCs may also have therapeutic potential in diabetes. METHODS: ISCs isolated from mouse islets were compared to mouse bone marrow MSCs by analysis of cell morphology; expression of cell-surface markers and extracellular matrix (ECM) components; proliferation; apoptosis; paracrine activity; and differentiation into adipocytes, chondrocytes and osteocytes. We also assessed the effects of co-culture with ISCs or MSCs on the insulin secretory capacity of islet beta cells. RESULTS: Although morphological similar, ISCs were functionally distinct from MSCs. Thus, ISCs were less proliferative and more apoptotic; they had different expression levels of important paracrine factors; and they were less efficient at differentiation down multiple lineages. Co-culture of mouse islets with ISCs enhanced glucose induced insulin secretion more effectively than co-culture with MSCs. CONCLUSIONS: ISCs are a specific sub-type of islet-derived stromal cells that possess biological behaviors distinct from MSCs. The enhanced beneficial effects of ISCs on islet beta cell function suggests that they may offer a therapeutic target for enhancing beta cell functional survival in diabetes.

Genetic lineage tracing reveals stellate cells as contributors to myofibroblasts in pancreas and islet fibrosis.

Pancreatic stellate cells (PSCs) are suggested to play an important role in the development of pancreas and islet fibrosis. However, the precise contributions and solid in vivo evidence of PSCs to the fibrogenesis remain to be elucidated. Here, we developed a novel fate-tracing strategy for PSCs by vitamin A administration in Lrat-cre; Rosa26-tdTomato transgenic mouse. The results showed that stellate cells give rise to 65.7% of myofibroblasts in cerulein-induced pancreatic exocrine fibrosis. In addition, stellate cells in islets increase and contribute partly to myofibroblasts pool in streptozocin-induced acute or chronic islet injury and fibrosis. Furthermore, we substantiated the functional contribution of PSCs to fibrogenesis of pancreatic exocrine and islet in PSCs ablated mice. We also found stellate cells' genetic ablation can improve pancreatic exocrine but not islet fibrosis. Together, our data indicates that stellate cells are vital/partial contributors to myofibroblasts in pancreatic exocrine/islet fibrosis.

Perilipin 2 Protects against Lipotoxicity-Induced Islet Fibrosis by Inducing Islet Stellate Cell Activation Phenotype Changes.

Aims: We explored whether and how perilipin 2 (Plin2) protected islets against lipotoxicity-induced islet dysfunction by regulating islet stellate cells (ISCs) activation. Methods: Six-week-old male rats were given a high-fat diet or a control diet for 28 weeks. Glucose metabolic phenotypes were assessed using glucose/insulin tolerance tests, masson, and immunohistochemical staining. ISCs activation levels were assessed from rats and palmitic acid- (PA-) treated cultured ISCs by immunofluorescence, Oil red O staining, electron microscopy, quantitative PCR, and western blotting. Changes in ISCs phenotype of activation degree and its underlying mechanisms were assessed by target gene lentiviral infection, high-performance liquid chromatography (HPLC), and western blotting. Results: Obese rats showed glucose intolerance, decreased endocrine hormone profiles, and elevated expression of α-smooth muscle actin (α-SMA), a polygonal appearance without cytoplasmic lipid droplets of ISCs in rats and isolated islets. PA-treated cultured ISCs exhibited faster proliferation and migration abilities with the induction of mRNA levels of lipid metabolism proteins, especially Plin2. The overexpression of Plin2 resulted in ISCs "re-quiescent" phenotypes associated with inhibition of the Smad3-TGF-ß signaling pathways. Conclusions: Our observations suggest a protective role of Plin2 in weakening ISCs activation. It may serve as a novel therapeutic target for preventing islet fibrosis for T2DM.

Screening and Identification of Key Genes for Activation of Islet Stellate Cell.

Background: It has been demonstrated that activated islet stellate cells (ISCs) play a critical role in islet fibrogenesis and significantly contribute to the progression of type 2 diabetes mellitus. However, the key molecules responsible for ISCs activation have not yet been determined. This study aimed to identify the potential key genes involved in diabetes-induced activation of ISCs. Method: Stellate cells were isolated from three 10-week-old healthy male Wistar rats and three Goto-Kakizaki (GK) rats. Cells from each rat were primary cultured under the same condition. A Genome-wide transcriptional sequence of stellate cells was generated using the Hiseq3000 platform. The identified differentially expressed genes were validated using quantitative real-time PCR and western blotting in GK rats, high fat diet (HFD) rats, and their controls. Results: A total of 204 differentially expressed genes (DEGs) between GK. ISCs and Wistar ISCs (W.ISCs) were identified, accounting for 0.58% of all the 35,362 genes detected. After the Gene Ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) enrichment analyses, the mRNA levels of these genes were further confirmed by real-time PCR in cultured ISCs. We then selected Fos, Pdpn, Bad as the potential key genes for diabetes-induced activation of ISCs. Finally, we confirmed the protein expression levels of FOS, podoplanin, and Bad by western blotting and immunofluorescence in GK rats, HFD rats, and their controls. The results showed that the expression level of FOS was significantly decreased, while podoplanin and Bad were significantly increased in GK.ISCs and HFD rats compared with controls, which were consistent with the expression of α-smooth muscle actin. Conclusions: A total of 204 DEGs were found between the GK.ISCs and W.ISCs. After validating the expression of potential key genes from GK rats and HFD rats, Fos, Pdpn, and Bad might be potential key genes involved in diabetes-induced activation of ISCs.

Prognostic Value of Podoplanin in Various Tumors.

BACKGROUND: The prognostic significance of podoplanin (PDPN) in tumor cells for cancer patients' survival remains controversial. Therefore, we performed this meta-analysis to clarify the relationship between the podoplanin-positive tumor cells and cancer prognosis. METHOD: Eligible studies were identified by searching the Pubmed and EBSCO online databases up to August 2019. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated to evaluate the correlation between podoplanin expression and overall survival (OS) and/or disease-free survival (DFS) and odds ratios (ORs) with 95% CIs severed as the summarized statistics for clinicopathological characteristic. RESULTS: A total of 2155 patients from 21 eligible studies were included. The results revealed that high expression of podoplanin was associated with a poor survival rate in cancer patients. Further subgroup analysis stratified by tumor type showed that podoplanin-positive tumor cell infiltration had a negative prognostic effect associated with survival in esophageal cancer and oropharyngeal cancer. In addition, high expression of these cells was significantly associated with N stage, T stage, TNM stage and vascular invasion. CONCLUSION: Our study suggests the over-expression of podoplanin might be a significant prognostic indicator for patients with esophageal and oropharyngeal cancer.

Prediction of Gut Microbial Community Structure and Function in Polycystic Ovary Syndrome With High Low-Density Lipoprotein Cholesterol.

Gut microbiota has been proved to be involved in the occurrence and development of many diseases, such as type 2 diabetes, obesity, coronary heart disease, etcetera. It provides a new idea for the pathogenesis of polycystic ovary syndrome (PCOS). Our study showed that the gut microbial community of PCOS with high low-density lipoprotein cholesterol (LDLC) has a noticeable imbalance. Gut microbiota of PCOS patients was significantly changed compared with CON, and these changes were closely related to LDLC. Gut microbiota may affect the metabolic level of PCOS patients through multiple metabolic pathways, and lipid metabolism disorder may further aggravate the imbalance of gut microbiota. Actinomycetaceae, Enterobacteriaceae and Streptococcaceae had high accuracy in the diagnosis of PCOS and the differentiation of subgroups, suggesting that they may play an important role in the diagnosis and treatment of PCOS in the future. Also, the model we built showed good specificity and sensitivity for distinguishing PCOS from CON (including L_CON and L_PCOS, H_CON and H_PCOS). In conclusion, this is the first report on the gut microbiota of PCOS with high LDLC, suggesting that in the drug development or treatment of PCOS patients, the difference of gut microbiota in PCOS patients with different LDLC levels should be fully considered.

Spinal P2X7R contributes to streptozotocin-induced mechanical allodynia in mice.

Painful diabetic neuropathy (PDN) is a diabetes mellitus complication. Unfortunately, the mechanisms underlying PDN are still poorly understood. Adenosine triphosphate (ATP)-gated P2X7 receptor (P2X7R) plays a pivotal role in non-diabetic neuropathic pain, but little is known about its effects on streptozotocin (STZ)-induced peripheral neuropathy. Here, we explored whether spinal cord P2X7R was correlated with the generation of mechanical allodynia (MA) in STZ-induced type 1 diabetic neuropathy in mice. MA was assessed by measuring paw withdrawal thresholds and western blotting. Immunohistochemistry was applied to analyze the protein expression levels and localization of P2X7R. STZ-induced mice expressed increased P2X7R in the dorsal horn of the lumbar spinal cord during MA. Mice injected intrathecally with a selective antagonist of P2X7R and P2X7R knockout (KO) mice both presented attenuated progression of MA. Double-immunofluorescent labeling demonstrated that P2X7R-positive cells were mostly co-expressed with Iba1 (a microglia marker). Our results suggest that P2X7R plays an important role in the development of MA and could be used as a cellular target for treating PDN.

CX3CR1 contributes to streptozotocin-induced mechanical allodynia in the mouse spinal cord.

Patients with diabetic peripheral neuropathy experience debilitating pain that significantly affects their quality of life (Abbott et al., 2011), by causing sleeping disorders, anxiety, and depression (Dermanovic Dobrota et al., 2014). The primary clinical manifestation of painful diabetic neuropathy (PDN) is mechanical hypersensitivity, also known as mechanical allodynia (MA) (Callaghan et al., 2012). MA's underlying mechanism remains poorly understood, and so far, based on symptomatic treatment, it has no effective therapy (Moore et al., 2014).

Improving the accuracy and efficacy of diagnosing polycystic ovary syndrome by integrating metabolomics with clinical characteristics: study protocol for a randomized controlled trial.

BACKGROUND: Polycystic ovary syndrome (PCOS) is a complex endocrine syndrome with poorly understood mechanisms. To provide patients with PCOS with individualized therapy, it is critical to precisely diagnose the phenotypes of the disease. However, the criteria for diagnosing the different phenotypes are mostly based on symptoms, physical examination and laboratory results. This study aims to compare the accuracy and efficacy of diagnosing PCOS by integrating metabolomic markers with common clinical characteristics. METHODS: This is a prospective, multicenter, analyst-blinded, randomized controlled trial. Participants will be grouped into (1) people without PCOS (healthy control group), (2) patients diagnosed with PCOS based on clinical indices (experimental group 1), and (3) patients diagnosed with PCOS based on metabolomic indices (experimental group 2). A total of 276 participants, including 60 healthy people and 216 patients with PCOS, will be recruited. The 216 patients with PCOS will be randomly assigned to the two experimental groups in a 1:1 ratio, and each group will receive a different 6-month treatment. The primary outcome for the experimental groups will be the effect of PCOS treatment. DISCUSSION: The results of this trial should help to determine whether using metabolomic indices is more accurate and effective than using clinical characteristics in diagnosing the phenotypes of PCOS. The results could provide a solid foundation for the accurate diagnosis of different PCOS subgroups and for future research on individualized PCOS therapy. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ID: ChiCTR-INR-1800016346. Registered 26 May 2018.