Volume electron microscopy reveals age-related ultrastructural differences of globular bush cell axons in mouse central auditory system.

In mammals, thick axonal calibers wrapped with heavy myelin sheaths are prevalent in the auditory nervous system. These features are crucial for fast traveling of nerve impulses with minimal attenuation required for sound signal transmission. In particular, the long-range projections from the cochlear nucleus - the axons of globular bush cells (GBCs) - to the medial nucleus of the trapezoid body (MNTB) are tonotopically organized. However, it remains controversial in gerbils and mice whether structural and functional adaptations are present among the GBC axons targeting different MNTB frequency regions. By means of high-throughput volume electron microscopy, we compared the GBC axons in full-tonotopy-ranged MNTB slices from the C57BL/6 mice at different ages. Our quantification reveals distinct caliber diameter and myelin profile of the GBC axons with endings at lateral and medial MNTB, arguing for modulation of functionally heterogeneous axon subgroups. In addition, we reported axon-specific differences in axon caliber, node of Ranvier, and myelin sheath among juvenile, adult, and old mice, indicating the age-related changes of GBC axon morphology over time. These findings provide structural insight into the maturation and degeneration of GBC axons with frequency tuning across the lifespan of mice.

Androgen-induced upregulation of CFTR in pancreatic ß-cell contributes to hyperinsulinemia in PCOS model.

PURPOSE: Polycystic ovarian syndrome (PCOS) is an endocrine-metabolic condition affecting 5-10% of reproductive-aged women and characterized by hyperandrogenism, insulin resistance (IR), and hyperinsulinemia. CFTR is known to be regulated by steroid hormones, and our previous study has demonstrated an essential role of CFTR in ß-cell function. This study aims to investigate the contribution of androgen and CFTR to hypersecretion of insulin in PCOS and the underlying mechanism. METHODS: We established a rat PCOS model by subcutaneously implanting silicon tubing containing Dihydrotestosterone (DHT). Glucose tolerance test with insulin levels was performed at 9 weeks after implantation. A rat ß-cell line RINm5F, a mouse ß-cell line ß-TC-6, and mouse islets were treated with DHT, and with or without the androgen antagonist flutamide for CFTR and insulin secretion-related functional assays or mRNA/protein expression measurement. The effect of CFTR inhibitors on DHT-promoted membrane depolarization, glucose-stimulated intracellular Ca2+ oscillation and insulin secretion were examined by membrane potential imaging, calcium imaging and ELISA, respectively. RESULTS: The DHT-induced PCOS model showed increased body weight, impaired glucose tolerance, and higher blood glucose and insulin levels after glucose stimulation. CFTR was upregulated in islets of PCOS model and DHT-treated cells, which was reversed by flutamide. The androgen receptor (AR) could bind to the CFTR promoter region, which was enhanced by DHT. Furthermore, DHT-induced membrane depolarization, enhanced glucose-stimulated Ca2+ oscillations and insulin secretion, which could be abolished by CFTR inhibitors. CONCLUSIONS: Excessive androgen enhances glucose-stimulating insulin secretion through upregulation of CFTR, which may contribute to hyperinsulinemia in PCOS.

Potassium channel-related genes are a novel prognostic signature for the tumor microenvironment of renal clear cell carcinoma.

Clear cell renal cell carcinoma (ccRCC) accounts for 80% of renal cell carcinomas (RCCs), and its morbidity and prognosis are unfavorable. Surgical resection is the first-line treatment for ccRCC, but the oncogenesis of ccRCC is very complex. With the development of high-throughput sequencing technology, it is necessary to analyze the transcriptome to determine more effective treatment methods. The tumor microenvironment (TME) is composed of tumor cells, various immune-infiltrating cells, fibroblasts, many cytokines, and catalysts. It is a complex system with a dynamic balance that plays an essential role in tumor growth, invasion, and metastasis. Previous studies have confirmed that potassium channels can affect the immune system, especially T lymphocytes that require potassium channel activation. However, the effect of potassium channels on the TME of ccRCC remains to be studied. Therefore, this study aims to construct a prognostic signature for ccRCC patients based on potassium ion channel-related genes (PCRGs), assess patient risk scores, and divide patients into high- and low-risk groups based on the cutoff value. In addition, we investigated whether there were differences in immune cell infiltration, immune activator expression, somatic mutations, and chemotherapeutic responses between the high- and low-risk groups. Our results demonstrate that the PCRG signature can accurately assess patient prognosis and the tumor microenvironment and predict chemotherapeutic responses. In summary, the PCRG signature could serve as an auxiliary tool for the precision treatment of ccRCC.

Angiotensin(1-7) activates MAS-1 and upregulates CFTR to promote insulin secretion in pancreatic ß-cells: the association with type 2 diabetes.

Objective: The beneficial effect of angiotensin(1-7) (Ang(1-7)), via the activation of its receptor, MAS-1, has been noted in diabetes treatment; however, how Ang(1-7) or MAS-1 affects insulin secretion remains elusive and whether the endogenous level of Ang(1-7) or MAS-1 is altered in diabetic individuals remains unexplored. We recently identified an important role of cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-activated Cl- channel, in the regulation of insulin secretion. Here, we tested the possible involvement of CFTR in mediating Ang(1-7)'s effect on insulin secretion and measured the level of Ang(1-7), MAS-1 as well as CFTR in the blood of individuals with or without type 2 diabetes. Methods: Ang(1-7)/MAS-1/CFTR pathway was determined by specific inhibitors, gene manipulation, Western blotting as well as insulin ELISA in a pancreatic ß-cell line, RINm5F. Human blood samples were collected from 333 individuals with (n = 197) and without (n = 136) type 2 diabetes. Ang(1-7), MAS-1 and CFTR levels in the human blood were determined by ELISA. Results: In RINm5F cells, Ang(1-7) induced intracellular cAMP increase, cAMP-response element binding protein (CREB) activation, enhanced CFTR expression and potentiated glucose-stimulated insulin secretion, which were abolished by a selective CFTR inhibitor, RNAi-knockdown of CFTR, or inhibition of MAS-1. In human subjects, the blood levels of MAS-1 and CFTR, but not Ang(1-7), were significantly higher in individuals with type 2 diabetes as compared to those in non-diabetic healthy subjects. In addition, blood levels of MAS-1 and CFTR were in significant positive correlation in type-2 diabetic but not non-diabetic subjects. Conclusion: These results suggested that MAS-1 and CFTR as key players in mediating Ang(1-7)-promoted insulin secretion in pancreatic ß-cells; MAS-1 and CFTR are positively correlated and both upregulated in type 2 diabetes.

Involvement of kisspeptin in androgen-induced hypothalamic endoplasmic reticulum stress and its rescuing effect in PCOS rats.

Endoplasmic reticulum (ER) stress, with adaptive unfolded protein response (UPR), is a key link between obesity, insulin resistance and type 2 diabetes, all of which are often present in the most common endocrine-metabolic disorder in women of reproductive age, polycystic ovary syndrome (PCOS), which is characterized with hyperandrogenism. However, the link between excess androgen and endoplasmic reticulum (ER) stress/insulin resistance in patients with polycystic ovary syndrome (PCOS) is unknown. An unexpected role of kisspeptin was reported in the regulation of UPR pathways and its involvement in the androgen-induced ER stress in hypothalamic neuronal cells. To evaluate the relationship of kisspeptin and ER stress, we detected kisspeptin and other factors in blood plasm of PCOS patients, rat models and hypothalamic neuronal cells. We detected higher testosterone and lower kisspeptin levels in the plasma of PCOS than that in non-PCOS women. We established a PCOS rat model by dihydrotestosterone (DHT) chronic exposure, and observed significantly downregulated kisspeptin expression and activated UPR pathways in PCOS rat hypothalamus compared to that in controls. Inhibition or knockdown of kisspeptin completely mimicked the enhancing effect of DHT on UPR pathways in a hypothalamic neuronal cell line, GT1-7. Kp10, the most potent peptide of kisspeptin, effectively reversed or suppressed the activated UPR pathways induced by DHT or thapsigargin, an ER stress activator, in GT1-7 cells, as well as in the hypothalamus in PCOS rats. Similarly, kisspeptin attenuated thapsigargin-induced Ca2+ response and the DHT- induced insulin resistance in GT1-7 cells. Collectively, the present study has revealed an unexpected protective role of kisspeptin against ER stress and insulin resistance in the hypothalamus and has provided a new treatment strategy targeting hypothalamic ER stress and insulin resistance with kisspeptin as a potential therapeutic agent.

Integrated analysis of microRNA and mRNA expression profiling identifies BAIAP3 as a novel target of dysregulated hsa-miR-1972 in age-related white matter lesions.

White matter lesions known as leukoaraiosis (LA) are cerebral white matter hyperintensities observed in elderly individuals. Currently, no reliable molecular biomarkers are available for monitoring their progression over time. To identify biomarkers for the onset and progression of LA, we analyzed whole blood-based, microRNA expression profiles of leukoaraiosis, validated those exhibiting significant microRNA changes in clinical subjects by means of quantitative real-time polymerase chain reactions and determined the function of miRNA in cell lines by means of microRNA mimic transfection assays. A total of seven microRNAs were found to be significantly down-regulated in leukoaraiosis. Among the microRNAs, hsa-miR-1972 was downregulated during the early onset phase of leukoaraiosis, as confirmed in independent patients, and it was found to target leukoaraiosis-dependent BAIAP3, decreasing its expression in 293T cell lines. Functional enrichment analysis revealed that significantly dysregulated miRNAs-mRNAs changes associated with the onset of leukoaraiosis were involved in neurogenesis, neuronal development, and differentiation. Taken together, the study identified a set of candidate microRNA biomarkers that may usefully monitor the onset and progression of leukoaraiosis. Given the enrichment of leukoaraiosis-associated microRNAs and mRNAs in neuron part and membrane system, BAIAP3 could potentially represent a novel target of hsa-miR-1972 in leukoaraiosis through which microRNAs are involved in the pathogenesis of white matter lesions.

[Effect of different pretreatment methods on dentin microleakage and bonding effect in caries].

PURPOSE：To evaluate the effect of different pretreatment methods on dentin microleakage and bonding effect of caries, so as to provide reference for clinical practice. METHODS: Sixty isolated caries were collected from Department of Oral and Maxillofacial Surgery, Affiliated Stomatological Hospital of Nanchang University from January 2020 to December 2020, and 120 dental samples were obtained by grinding them into two halves along the long axis of the precursor teeth. According to different pretreatment methods, they were divided into group A (2%NaClO), group B (2% chlorhexidine) and group C (75% ethanol). The bond strength, microtensile test and microleakage of the three groups of teeth were compared. SPSS 24.0 software package was used for statistical analysis of the data. RESULTS: The bond strength of the three groups from high to low was group A, group B and group C(P＜0.05); the fracture type of the three groups was compared, mixed damage of group A was lower than that of group B and group C； microleakage of the three groups was compared, and microleakage of group A was better than that of group B and group C(P＜0.05). CONCLUSIONS: Pre-treatment with 2%NaClO can reduce dentin microleakage and significantly improve the bonding strength of teeth, which is conducive to the promotion and application in the treatment of dental diseases.

Moderate Hydrogen Peroxide Postconditioning Ameliorates Ischemia/Reperfusion Injury in Cardiomyocytes via STAT3-Induced Calcium, ROS, and ATP Homeostasis.

INTRODUCTION: Moderate hydrogen peroxide postconditioning (H2O2PoC) activates signal transducer and activator of transcription 3 (STAT3) to alleviate mitochondrial calcium overload during cardiac ischemia/reperfusion (I/R). However, the initial time window of STAT3-induced calcium hemostasis, the production of reactive oxygen species (ROS) and adenosine triphosphate (ATP) in H2O2PoC, and its regulated mechanism remain unknown. This study aimed to investigate H2O2PoC-induced homeostasis of calcium, ROS and ATP, and the role of STAT3 in the regulation. METHODS: Isolated rat cardiomyocytes were exposed to H2O2PoC and Janus kinase 2 (JAK2)/STAT3 inhibitor AG490 during I/R. Ca2+ transients, cell contraction, intracellular calcium concentration, ROS production, ATP contents, phosphorylation of STAT3, gene and protein expression of manganese superoxide dismutase (MnSOD), metallothionein 1 (MT1) and metallothionein 2 (MT2), as well as activities of mitochondrial complex I and complex II were detected. RESULTS: Moderate H2O2PoC improved post-ischemic Ca2+ transients and cell contraction recovery as well as alleviated cytosolic and mitochondrial calcium overload, which were abrogated by AG490 in rat cardiomyocytes. Moderate H2O2PoC increased ROS production and rate of ROS production at early reperfusion in rat I/R cardiomyocytes, and this phenomenon was also abrogated by AG490. Notably, the expression of phosphorylated nuclear STAT3; gene and protein expression of MnSOD, MT1, and MT2; and activities of mitochondrial complex I and complex II were upregulated by moderate H2O2PoC but downregulated by AG490. CONCLUSION: These findings indicated that the cardioprotection of moderate H2O2PoC against cardiac I/R could be associated with activated STAT3 at early reperfusion to maintain calcium, ROS, and ATP homeostasis in rat cardiomyocytes.

[LncRNA NEAT1 regulates proliferation, migration and invasion of tongue squamous cell carcinoma cells by regulating miR-339-5p/ITGA3 axis].

PURPOSE: To investigate the molecular mechanism of LncRNA NEAT1 regulating proliferation, migration and invasion of tongue squamous cell carcinoma cells by regulating miR-339-5p/ITGA3 axis. METHODS: qRT-PCR and Western blot were used to detect the expression of NEAT1, miR-339-5p, ITGA3 mRNA and ITGA3 protein in 25 cases of human tongue squamous cell carcinoma, its corresponding adjacent tissues, human normal oral mucosal cell line HOK and human tongue squamous cell carcinoma cell lines TSCCA, CAL27, SCC15 and HN13. CAL27 cell lines that inhibited NEAT1 and overexpressed miR-339-5p were constructed, respectively. Cell viability was detected by MTT assay, cell numbers of migration and invasion were detected by Transwell assay, and the expression of Cyclin D1 and MMP-9 proteins were detected by Western blotting. The dual luciferase reporter gene was used to verify the targeting relationship of NEAT1, miR-339-5p and ITGA3, and the regulatory relationship was detected by Western blotting and qRT-PCR. SPSS 17.0 software package was used for statistical analysis of the data. RESULTS: Compared with normal human oral mucosal cell line HOK, the expression of NEAT1 and ITGA3 was up-regulated, while the expression of miR-339-5p was down-regulated in human tongue squamous cell carcinoma cell lines. Inhibition of NEAT1 or over-expression of miR-339-5p significantly inhibited proliferation, migration and invasion of CAL27 cells, and significantly inhibited expression of Cyclin D1 and MMP-9 proteins. Dual luciferase reporter gene assay confirmed that NEAT1 directly interacted with miR-339-5p and suppressed its expression. miR-339-5p negatively regulated ITGA3 expression. Inhibition of NEAT1 reversed the inhibitory effect of the inhibition of miR-339-5p on proliferation, migration and invasion of CAL27 cells. CONCLUSIONS: LncRNA NEAT1 promotes proliferation, migration and invasion of tongue squamous cell carcinoma cells by down-regulating miR-339-5p/ITGA3 axis.

The Associations of PMF1, ICAM1, AGT, TRIM65, FBF1, and ACOX1 Variants With Leukoaraiosis in Chinese Population.

Background: Leukoaraiosis (LA) is shown as white matter hyperintensities on T2-weighted magnetic resonance imaging brain scans. Together with candidate gene association studies (CGAS), multiple genome-wide association studies (GWAS) have reported large numbers of single nucleotide polymorphisms (SNPs) to be associated with LA in European populations. To date, no replication studies have been reported in independent Chinese samples. Methods: Here, we performed a candidate gene association study comprising 220 Chinese subjects with LA and 50 controls. Thirty-nine polymorphisms on 32 risk genes were selected from previous studies, and they were genotyped through matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Genetic association analysis was firstly performed in all subjects with LA. Then, the same analysis was conducted in the six random sampling cohorts of 50 LA patients, respectively. Data analyses on the associations of SNPs with LA risk were evaluated through Pearson's χ2 and multivariate logistic regression tests. Results: We found that eight polymorphisms in six genes (PMF1, ICAM1, TRIM65, AGT, FBF1, and ACOX1) were significantly associated with LA in the genetic association tests. Except for those eight gene variants, 24 other polymorphisms were not found to be significantly associated with LA in general genetic model, dominant model, recessive model, or multiplicative model. Among those eight polymorphisms, rs2984613 in PMF1 showed significant association with LA in the cohort of 220 LA subjects, and such significant association remained in both general genetic model (OR: 0.262, 95% CI: 0.091-0.752, p adj = 0.030) and recessive model (OR: 0.323, 95% CI: 0.119-0.881, p adj = 0.038) when controlling for clinical variables. Seven other significant variants (rs5498 in ICAM1, rs699 in AGT, rs2305913 in FBF1, rs1135640 in ACOX1, and rs3760128, rs7214628, and rs7222757 in TRIM65) were identified in those six random sampling tests that were conducted in the adjusted cohorts of 50 LA patients. In addition, except for rs699 which showed detrimental effect and represented a risk variant for LA, seven other polymorphisms seemed to exert protective effects on LA and to reduce the risk of LA. It is necessary to confirm these associations in an independent cohort. Conclusions: This first replication study on multiple genes in an independent Chinese population did not replicate any risk polymorphisms for LA other than rs 699 in AGT but revealed the significantly negative associations of PMF1, ICAM1, TRIM65, FBF1, and ACOX1 polymorphisms with LA. It not only supported the strong ethnic differences in the genetics of LA but also indicated that those six identified genes may be involved in Chinese white matter lesions. Larger scales of CGAS and GWAS are necessary to confirm and decipher those ethnic-Han specific risk genes for LA in China.

MRP4 sustains Wnt/ß-catenin signaling for pregnancy, endometriosis and endometrial cancer.

Rationale: Abnormal Wnt/ß-catenin signaling in the endometrium can lead to both embryo implantation failure and severe pathogenic changes of the endometrium such as endometrial cancer and endometriosis. However, how Wnt/ß-catenin signaling is regulated in the endometrium remains elusive. We explored possible regulation of Wnt/ß-catenin signaling by multi-drug resistance protein 4 (MRP4), a potential target in cancer chemotherapy, and investigated the mechanism. Methods: Knockdown of MRP4 was performed in human endometrial cells in vitro or in a mouse embryo-implantation model in vivo. Immunoprecipitation, immunoblotting and immunofluorescence were used to assess protein interaction and stability. Wnt/ß-catenin signaling was assessed by TOPflash reporter assay and quantitative PCR array. Normal and endometriotic human endometrial tissues were examined. Data from human microarray or RNAseq databases of more than 100 participants with endometriosis, endometrial cancer or IVF were analyzed. In vitro and in vivo tumorigenesis was performed. Results: MRP4-knockdown, but not its transporter-function-inhibition, accelerates ß-catenin degradation in human endometrial cells. MRP4 and ß-catenin are co-localized and co-immunoprecipitated in mouse and human endometrium. MRP4-knockdown in mouse uterus reduces ß-catenin levels, downregulates a series of Wnt/ß-catenin target genes and impairs embryo implantation, which are all reversed by blocking ß-catenin degradation. Analysis of human endometrial biopsy samples and available databases reveals significant and positive correlations of MRP4 with ß-catenin and Wnt/ß-catenin target genes in the receptive endometrium in IVF, ectopic endometriotic lesions and endometrial cancers. Knockdown of MRP4 also inhibits in vitro and in vivo endometrial tumorigenesis. Conclusion: A previously undefined role of MRP4 in stabilizing ß-catenin to sustain Wnt/ß-catenin signaling in endometrial cells is revealed for both embryo implantation and endometrial disorders, suggesting MRP4 as a theranostic target for endometrial diseases associated with Wnt/ß-catenin signaling abnormality.

Susceptibility Weighted Imaging (SWI) Recommended as a Regular Magnetic Resonance Diagnosis for Vascular Dementia to Identify Independent Idiopathic Normal Pressure Hydrocephalus Before Ventriculo-Peritoneal (V-P) Shunt Treatment: A Case Study.

Idiopathic normal pressure hydrocephalus (INPH) with comorbid vascular dementia (VD) often have poor response to ventriculo-peritoneal (V-P) shunt. Here, three patients over the age of 60 came to the hospital with the similar clinical symptoms, Evan index over 0.3, mini-mental state examination (MMSE) score <27, and cerebrospinal fluid (CSF) pressure under 200 mmH2O. They accepted conventional brain imaging scanning, followed by magnetic resonance-susceptibility weighted imaging (MR-SWI) scanning. We found that MR-SWI could distinguish INPH from leukoaraiosis (LA) and cerebral amyloid angiopathy (CAA), through cerebral microbleed (CMB) images, sharply. We highly recommended incorporation of MR-SWI into INPH international guidance as a routine pre-operative diagnostic method preceding V-P shunt treatment.

Activation of the epithelial sodium channel (ENaC) leads to cytokine profile shift to pro-inflammatory in labor.

The shift of cytokine profile from anti- to pro-inflammatory is the most recognizable sign of labor, although the underlying mechanism remains elusive. Here, we report that the epithelial sodium channel (ENaC) is upregulated and activated in the uterus at labor in mice. Mechanical activation of ENaC results in phosphorylation of CREB and upregulation of pro-inflammatory cytokines as well as COX-2/PGE2 in uterine epithelial cells. ENaC expression is also upregulated in mice with RU486-induced preterm labor as well as in women with preterm labor. Interference with ENaC attenuates mechanically stimulated uterine contractions and significantly delays the RU486-induced preterm labor in mice. Analysis of a human transcriptome database for maternal-fetus tissue/blood collected at onset of human term and preterm births reveals significant and positive correlation of ENaC with labor-associated pro-inflammatory factors in labored birth groups (both term and preterm), but not in non-labored birth groups. Taken together, the present finding reveals a pro-inflammatory role of ENaC in labor at term and preterm, suggesting it as a potential target for the prevention and treatment of preterm labor.

DNA Methylation Profiling Reveals the Change of Inflammation-Associated ZC3H12D in Leukoaraiosis.

Leukoaraiosis (LA) is neuroimaging abnormalities of the cerebral white matter in elderly people. However, the molecular mechanisms underlying the cerebral white matter lesions remain unclear. Here, we reported an epigenetic basis and potential pathogenesis for this complex illness. 317 differentially methylated genes were identified to distinguish the mechanism of occurrence and progression of LA. Gene-Ontology pathway analysis highlighted that those genes with epigenetic changes are mostly involved in four major signaling pathways including inflammation and immune response-associated processes (antigen processing and presentation, T cell costimulation and interferon-γ-mediated signaling pathway), synapse assembly, synaptic transmission and cell adhesion. Moreover, immune response seems to be specific to LA occurrence and subsequent disruption of nervous system functions could drive the progression of LA. The significant change of inflammation-associated ZC3H12D in promoter methylation and mRNA expression was implicated in the occurrence of LA, suggesting its potential functions in the molecular mechanism of LA. Our results suggested that inflammation-associated signaling pathways were involved in the pathogenesis of LA and ZC3H12D may contribute to such inflammatory process underlying LA, and further echoed it as a neuroinflammatory disorder in central nervous system (CNS).

Identification of two novel genes SLC15A2 and SLCO1B3 associated with maintenance dose variability of warfarin in a Chinese population.

Warfarin is a commonly prescribed and effective oral anticoagulant. Genetic polymorphisms associated with warfarin metabolism and sensitivity have been implicated in the wide inter-individual dose variation that is observed. Several algorithms integrating patients' clinical characteristics and genetic polymorphism information have been explored to predict warfarin dose. However, most of these algorithms could explain only over half of the variation in a warfarin maintenance dose, suggesting that additional genetic factors may exist and need to be identified. Here, a drug absorption, distribution, metabolism and excretion (ADME) Core Panel Kit-based pharmacogenetic study was performed to screen for warfarin dose-associated SNP sites in Han-Chinese population patients taking warfarin therapy, and the screen was followed by pyrosequencing-based validation. Finally, we confirmed that the common variant rs9923231 in VKORC1 and two novel genes, SLC15A2 (rs1143671 and rs1143672) and SLCO1B3 (rs4149117 and rs7311358), are associated with the warfarin maintenance dose. As has been shown for those carriers with the variant rs9923231 in VKORC1, it was suggested that those subjects with homozygous minor alleles in those four SNPs should take a lower warfarin dose than those carrying the wild type alleles. Together with the established predictor rs9923231 in VKORC1, those four novel variants on SLC15A2 and SLCO1B3 should be considered as useful biomarkers for warfarin dose adjustment in clinical practice in Han-Chinese populations.

Abnormal CFTR Affects Glucagon Production by Islet α Cells in Cystic Fibrosis and Polycystic Ovarian Syndrome.

Glucagon, produced by islet α cells, functions to increase blood glucose. Abnormal glucose levels are often seen in cystic fibrosis (CF), a systematic disease caused by mutations of the CF transmembrane conductance regulator (CFTR), and in polycystic ovarian syndrome (PCOS), an endocrine disorder featured with hyperandrogenism affecting 5-10% women of reproductive age. Here, we explored the role of CFTR in glucagon production in α cells and its possible contribution to glucagon disturbance in CF and PCOS. We found elevated fasting glucagon levels in CFTR mutant (DF508) mice compared to the wildtypes. Glucagon and prohormone convertase 2 (PC2) were also upregulated in CFTR inhibitor-treated or DF508 islets, as compared to the controls or wildtypes, respectively. Dihydrotestosterone (DHT)-induced PCOS rats exhibited significantly lower fasting glucagon levels with higher CFTR expression in α cells compared to that of controls. Treatment of mouse islets or αTC1-9 cells with DHT enhanced CFTR expression and reduced the levels of glucagon and PC2. The inhibitory effect of DHT on glucagon production was blocked by CFTR inhibitors in mouse islets, and mimicked by overexpressing CFTR in αTC1-9 cells with reduced phosphorylation of the cAMP/Ca2+ response element binding protein (p-CREB), a key transcription factor for glucagon and PC2. These results revealed a previously undefined role of CFTR in suppressing glucagon production in α-cells, defects in which may contribute to glucose metabolic disorder seen in CF and PCOS.

Glucose-Sensitive CFTR Suppresses Glucagon Secretion by Potentiating KATP Channels in Pancreatic Islet α Cells.

The secretion of glucagon by islet α cells is normally suppressed by high blood glucose, but this suppressibility is impaired in patients with diabetes or cystic fibrosis (CF), a disease caused by mutations in the gene encoding CF transmembrane conductance regulator (CFTR), a cyclic adenosine monophosphate-activated Cl- channel. However, precisely how glucose regulates glucagon release remains controversial. Here we report that elevated glucagon secretion, together with increased glucose-induced membrane depolarization and Ca2+ response, is found in CFTR mutant (DF508) mice/islets compared with the wild-type. Overexpression of CFTR in AlphaTC1-9 cells results in membrane hyperpolarization and reduced glucagon release, which can be reversed by CFTR inhibition. CFTR is found to potentiate the adenosine triphosphate-sensitive K+ (KATP) channel because membrane depolarization and whole-cell currents sensitive to KATP blockers are significantly greater in wild-type/CFTR-overexpressed α cells compared with that in DF508/non-overexpressed cells. KATP knockdown also reverses the suppressive effect of CFTR overexpression on glucagon secretion. The results reveal that by potentiating KATP channels, CFTR acts as a glucose-sensing negative regulator of glucagon secretion in α cells, a defect of which may contribute to glucose intolerance in CF and other types of diabetes.

Incidence and risk factors of leukoaraiosis from 4683 hospitalized patients: A cross-sectional study.

Leukoaraiosis (LA) refers to white matter hyperintensities or white matter lesions (WMLs) on magnetic resonance imaging (MRI) scans of the brain; this disease is associated with an increased risk of stroke, dementia, and cognitive decline. The aims of the study are to assess the incidence of LA and its associated risk factors in a Chinese population.A hospital-based cross-sectional study was conducted that included 4683 patients who were 40 years or older. Data collected included age, sex, hypertension, diabetes, smoking, drinking, homocysteine (HCY), and low-density lipoprotein cholesterol (LDL-C) levels in the blood in addition to brain MRI information. We examined the relationship of those putative risk factors with LA, LA occurrence, and LA progression through single-factor and multivariate analyses.Of the total subjects, 58.3% (2731/4683 cases) suffered from LA. LA was more frequent amongst elderly females, particularly in those older than 60, compared to men. The incidence of LA increased with age. Age, sex, hypertension, diabetes, smoking, and HCY levels all were risk factors for LA. Amongst those risk factors, both smoking and high HCY levels were associated with the onset process of LA. Moreover, the multivariate logistic analysis revealed that both drinking and abnormal LDL-C levels were positive regulators in the progression process of LA.This study revealed that the incidence of LA is high in hospitalized patients in China; moreover, age, sex, hypertension, diabetes mellitus, smoking, drinking, and abnormal HCY and LDL-C levels were found to be associated with overall LA risk, LA onset, or LA progression. These results provide insight into strategies for the prevention and treatment of LA.

A Novel CCM2 Gene Mutation Associated with Familial Cerebral Cavernous Malformation.

Background: Cerebral cavernous malformations (CCMs) are common vascular malformations that predominantly arise in the central nervous system and are mainly characterized by enlarged vascular cavities without intervening brain parenchyma. Familial CCMs (FCCMs) is inherited in an autosomal dominant pattern with incomplete penetrance and variable symptoms. Methods: Mutations of three pathogenic genes, CCM1, CCM2, and CCM3, were investigated by direct DNA sequencing in a Chinese family with multiple CCM lesions. Results: Four heterozygous variants in the CCM2 gene, including one deletion (c.95delC), a missense mutation (c.358G>A, p.V120I), one silent mutation (c.915G>A, p.T305T), and a substitution (c. *1452 T>C), were identified in the subjects with multiple CCM lesions, but not in a healthy sibling. Among these variants, the c.95delC deletion is a novel mutation which is expected to cause a premature termination codon. It is predicted to produce a truncated CCM2 protein lacking the PTB and C-terminal domains, thus disrupting the molecular functions of CCM2. Conclusions: The novel truncating mutation in the CCM2 gene, c.95delC, may be responsible for multiple CCM lesions in a part of FCCM. In addition, it may represent a potential genetic biomarker for early diagnosis of FCCM.