KCNH6 is essential for insulin secretion by regulating intracellular ER Ca2+ store.

Appropriate Ca2+ concentration in the endoplasmic reticulum (ER), modulating cytosolic Ca2+ signal, serves significant roles in physiological function of pancreatic ß cells. To maintaining ER homeostasis, Ca2+ movement across the ER membrane is always accompanied by a simultaneous K+ flux in the opposite direction. KCNH6 was proven to modulate insulin secretion by controlling plasma membrane action potential duration and intracellular Ca2+ influx. Meanwhile, the specific function of KCNH6 in pancreatic ß-cells remains unclear. In this study, we found that KCNH6 exhibited mainly ER localization and Kcnh6 ß-cell-specific knockout (ßKO) mice suffered from abnormal glucose tolerance and impaired insulin secretion in adulthood. ER Ca2+ store was overloaded in islets of ßKO mice, which contributed to ER stress and ER stress-induced apoptosis in ß cells. Next, we verified that ethanol treatment induced increases in ER Ca2+ store and apoptosis in pancreatic ß cells, whereas adenovirus-mediated KCNH6 overexpression in islets attenuated ethanol-induced ER stress and apoptosis. In addition, tail-vein injections of KCNH6 lentivirus rescued KCNH6 expression in ßKO mice, restored ER Ca2+ overload and attenuated ER stress in ß cells, which further confirms that KCNH6 protects islets from ER stress and apoptosis. These data suggest that KCNH6 on the ER membrane may help to stabilize intracellular ER Ca2+ stores and protect ß cells from ER stress and apoptosis. In conclusion, our study reveals the protective potential of KCNH6-targeting drugs in ER stress-induced diabetes.

Vitexin inhibits APEX1 to counteract the flow-induced endothelial inflammation.

Vascular endothelial cells are exposed to shear stresses with disturbed vs. laminar flow patterns, which lead to proinflammatory vs. antiinflammatory phenotypes, respectively. Effective treatment against endothelial inflammation and the consequent atherogenesis requires the identification of new therapeutic molecules and the development of drugs targeting these molecules. Using Connectivity Map, we have identified vitexin, a natural flavonoid, as a compound that evokes the gene-expression changes caused by pulsatile shear, which mimics laminar flow with a clear direction, vs. oscillatory shear (OS), which mimics disturbed flow without a clear direction. Treatment with vitexin suppressed the endothelial inflammation induced by OS or tumor necrosis factor-α. Administration of vitexin to mice subjected to carotid partial ligation blocked the disturbed flow-induced endothelial inflammation and neointimal formation. In hyperlipidemic mice, treatment with vitexin ameliorated atherosclerosis. Using SuperPred, we predicted that apurinic/apyrimidinic endonuclease1 (APEX1) may directly interact with vitexin, and we experimentally verified their physical interactions. OS induced APEX1 nuclear translocation, which was inhibited by vitexin. OS promoted the binding of acetyltransferase p300 to APEX1, leading to its acetylation and nuclear translocation. Functionally, knocking down APEX1 with siRNA reversed the OS-induced proinflammatory phenotype, suggesting that APEX1 promotes inflammation by orchestrating the NF-κB pathway. Animal experiments with the partial ligation model indicated that overexpression of APEX1 negated the action of vitexin against endothelial inflammation, and that endothelial-specific deletion of APEX1 ameliorated atherogenesis. We thus propose targeting APEX1 with vitexin as a potential therapeutic strategy to alleviate atherosclerosis.

Disturbed Flow-Facilitated Margination and Targeting of Nanodisks Protect against Atherosclerosis.

Disturbed blood flow induces endothelial pro-inflammatory responses that promote atherogenesis. Nanoparticle-based therapeutics aimed at treating endothelial inflammation in vasculature where disturbed flow occurs may provide a promising avenue to prevent atherosclerosis. By using a vertical-step flow apparatus and a microfluidic chip of vascular stenosis, herein, it is found that the disk-shaped versus the spherical nanoparticles exhibit preferential margination (localization and adhesion) to the regions with the pro-atherogenic disturbed flow. By employing a mouse model of carotid partial ligation, superior targeting and higher accumulation of the disk-shaped particles are also demonstrated within disturbed flow areas than that of the spherical particles. In hyperlipidemia mice, administration of disk-shaped particles loaded with hypomethylating agent decitabine (DAC) displays greater anti-inflammatory and anti-atherosclerotic effects compared with that of the spherical counterparts and exhibits reduced toxicity than "naked" DAC. The findings suggest that shaping nanoparticles to disk is an effective strategy for promoting their delivery to atheroprone endothelia.

Effects of Umbilical Cord Milking on Anemia in Preterm Infants: A Multicenter Randomized Controlled Trial.

OBJECTIVE: This study aimed to investigate whether umbilical cord milking (UCM) prevents and controls anemia in preterm infants, as compared with immediate cord clamping (ICC). STUDY DESIGN: Pregnant women delivering at <34 weeks' gestation in four hospitals were randomly assigned to undergo UCM or ICC from July 2017 to June 2019. Hematological parameters and iron status were collected and analyzed as primary outcomes at 24 hours, 1 week, 2 weeks, and 6 months after delivery. RESULTS: Neonates receiving UCM had significant higher levels of hemoglobin (Hb), hematocrit, and serum iron (p < 0.05). Lower prevalence of anemia and lower need for transfusions were noted in UCM group. Although UCM was associated with prolonged duration of phototherapy, the maximum levels of bilirubin were similar between two groups (p > 0.05). CONCLUSION: UCM is an effective intervention to help preterm infants experience less anemia with the potential to increase blood volume, as seen by higher Hb levels and more enhanced iron stores.

Clinical activity changes in the neurology department of Wenzhou during the COVID-19 pandemic: an observational analysis.

OBJECTIVE: To explore the activity changes in neurology clinical practice that have occurred in tertiary public hospitals during the COVID-19 pandemic. METHODS: Outpatient and inpatient data from the neurology department were extracted from the electronic medical record system of three tertiary Grade A hospitals in Wenzhou. Data were analyzed across 5 months following the beginning of the pandemic (from January 13 to May 17) and compared with the same period in 2019. Data on reperfusion therapy for acute infarction stroke were extracted monthly from January to April. RESULTS: The number of outpatients declined from 102,300 in 2019 to 75,154 in 2020 (26.54%), while the number of inpatients in the three tertiary Grade A hospitals decreased from 4641 to 3437 (25.94%). The latter trend showed a significant drop from the 3rd week to the 7th week. The number of patients in these hospitals decreased significantly, and a significant drop was seen in the neurology department. As usual, stroke was the most common disease observed; however, anxiety/depression and insomnia increased dramatically in the outpatient consultation department. CONCLUSIONS: The results of our study revealed the effects of the COVID-19 pandemic in the clinical practice of neurology in Wenzhou during the outbreak. Understanding the pandemic's trends and impact on neurological patients and health systems will allow for better preparation of neurologists in the future.

[New insights into vascular mechanobiology: roles of matrix mechanics in regulating smooth muscle cell function].

Vascular smooth muscle cell (vSMC) is the predominant cell type in the blood vessel wall and is constantly subjected to a complex extracellular microenvironment. Mechanical forces that are conveyed by changes in stiffness/elasticity, geometry and topology of the extracellular matrix have been indicated by experimental studies to affect the phenotype and function of vSMCs. vSMCs perceive the mechanical stimuli from matrix via specialized mechanosensors, translate these stimuli into biochemical signals controlling gene expression and activation, with the consequent modulation in controlling various aspects of SMC behaviors. Changes in vSMC behaviors may further cause disruption of vascular homeostasis and then lead to vascular remodeling. A better understanding of how SMC senses and transduces mechanical forces and how the extracellular mechano-microenvironments regulate SMC phenotype and function may contribute to the development of new therapeutics for vascular diseases.

VAMP3 and SNAP23 mediate the disturbed flow-induced endothelial microRNA secretion and smooth muscle hyperplasia.

Vascular endothelial cells (ECs) at arterial branches and curvatures experience disturbed blood flow and induce a quiescent-to-activated phenotypic transition of the adjacent smooth muscle cells (SMCs) and a subsequent smooth muscle hyperplasia. However, the mechanism underlying the flow pattern-specific initiation of EC-to-SMC signaling remains elusive. Our previous study demonstrated that endothelial microRNA-126-3p (miR-126-3p) acts as a key intercellular molecule to increase turnover of the recipient SMCs, and that its release is reduced by atheroprotective laminar shear (12 dynes/cm2) to ECs. Here we provide evidence that atherogenic oscillatory shear (0.5 ± 4 dynes/cm2), but not atheroprotective pulsatile shear (12 ± 4 dynes/cm2), increases the endothelial secretion of nonmembrane-bound miR-126-3p and other microRNAs (miRNAs) via the activation of SNAREs, vesicle-associated membrane protein 3 (VAMP3) and synaptosomal-associated protein 23 (SNAP23). Knockdown of VAMP3 and SNAP23 reduces endothelial secretion of miR-126-3p and miR-200a-3p, as well as the proliferation, migration, and suppression of contractile markers in SMCs caused by EC-coculture. Pharmacological intervention of mammalian target of rapamycin complex 1 in ECs blocks endothelial secretion and EC-to-SMC transfer of miR-126-3p through transcriptional inhibition of VAMP3 and SNAP23. Systemic inhibition of VAMP3 and SNAP23 by rapamycin or periadventitial application of the endocytosis inhibitor dynasore ameliorates the disturbed flow-induced neointimal formation, whereas intraluminal overexpression of SNAP23 aggravates it. Our findings demonstrate the flow-pattern-specificity of SNARE activation and its contribution to the miRNA-mediated EC-SMC communication.

DNA methyltransferase 1 and Krüppel-like factor 4 axis regulates macrophage inflammation and atherosclerosis.

Macrophage-mediated inflammatory responses occur throughout all stages of atherosclerosis. DNA methylation is one of the critical epigenetic mechanisms and is associated with the development of atherosclerosis. The underlying mechanism of epigenetic regulation of macrophage inflammation (M1 activation) remains unclear. Here we aim to study the role of DNA methyltransferase 1 (DNMT1) in modulating macrophage inflammation and atherosclerosis. DNMT1 expression is up-regulated in THP-1-derived macrophages upon treatment with lipopolysaccharide (LPS) and interferon-gamma (IFN-γ). Overexpression of DNMT1 promotes the LPS- and IFN-γ-induced M1 activation whereas inhibition of DNMT1 attenuates it. Consistently, DNMT1 expression is elevated in macrophages in atherosclerotic plaques from human and mouse specimens; compared with the Dnmt1wild-type, myeloid Dnmt1 deficiency in mice in an Apolipoprotein E (ApoE) knockout background or receiving AAV-PSCK9 injection and carotid partial ligation results in ameliorated atheroma formation and suppressed plaque inflammation. The promoter regions of atheroprotective Krüppel-like factor 4 (KLF4) are hypermethylated in M1- activated macrophages. DNMT1 down-regulates the expression of KLF4, probably through catalyzing DNA methylation of the promoter regions of KLF4. Gain- and loss-of function study of KLF4 indicates that the DNMT1-mediated macrophage M1 activation is dependent on KLF4. Our data demonstrate a proatherogenic role for DNMT1 as a defining factor in macrophage inflammation both in vitro and in vivo. DNMT1 promotes macrophage M1 activation by suppressing KLF4 expression. Thus macrophage-specific DNMT1 inhibition may provide an attractive therapeutic potential to prevent or reduce atherosclerosis.

Bioactivity-Guided Screening of Wound-Healing Active Constituents from American Cockroach (Periplaneta americana).

Ethanol extract (EE) from Periplaneta americana (PA) is the main ingredient of Kangfuxin, which is a popular traditional chinese medicine (TCM) and has long been used for the clinical treatment of burns, wounds and ulcers. We compared the wound-healing activities of three extracts of PA using cutaneous wound-healing in mice as the bioactivity model. These three extracts were EE, total polysaccharide and total protein. We also tracked bioactive fractions in the EE by organic reagent extraction, column chromatography and HPLC. Seven compounds were successfully identified from the water elution fraction of the EE of PA using UPLC-MS. Among these compounds, four compounds (P2, P3, P4, P5(1)) were first reported in PA. Some of these compounds have been previously reported to have various pharmacological activities that could contribute to the high wound-healing activity of PA.

[The Effect of p-JAK1/p-STAT3 Signaling Way in Intervening NAFLD by Blueberry Probiotic Serum].

OBJECTIVES: To explore the mechanism of interlukin-22 (IL-22)-mediated phosphor-Janus kinase-1(p-JAK1)/phosphor-signal transducer and activator of transcription 3 (p-STAT3) signaling way in the experiment of improving non-alcholic fatty liver disease (NAFLD) by blueberry probiotic serum. METHODS: The rat serums with low-, medium-, and high-dose of 10% blueberry probiotics, as well as saline were prepared. NAFLD model was built by inducing normal liver cell line L-02 with free fatty acid (FFA).NAFLD model cells were cultured with saline serum (model group), low-, medium-, and high-dose blueberry probiotics serums (low-, medium-, and high-dose serum groups) , respectively .Normal liver cell group (normal group) was cultured with saline serum . Oil Red O staining was used to detect the lipid deposition in the cells; the intracellular level of triglyceride (TG) was quantitatively determined; the gene and protein expressions of IL-22, p-JAK1, p-STAT3, sterol-regulatory element binding protein-1c (SREBP-1c ) were detected by RT-PCR, Western blot and immunofluorescence methods. RESULTS: Twenty-four hours after modeling, a large amount of lipid deposition could be observed in model group. Compared with normal group, model group showed lower gene and protein expression levels of IL-22, p-JAK1 and p-STAT3 (P <0.01), and higher SREBP-1c and TG levels (P <0.01).Compared with model group, TG level and the lipid deposition in low-, medium-, and high-dose blueberry probiotics serum groups were gradually reduced. High-dose serum group showed higher gene and protein expression levels of IL-22, p-JAK1, p-STAT3 and lower SREBP-1c compared with the model, low-, and medium-dose serum groups (P <0.01). No significant [CM(155.3mm]differences in gene and protein levels between low- andmedium-doseserum groups were found (P >0.05). CONCLUSION: The blueberry probiotics could antagonize the NAFLD via p-JAK1/p-STAT3 signaling way.

Paroxetine ameliorates lipopolysaccharide-induced microglia activation via differential regulation of MAPK signaling.

BACKGROUND: Paroxetine, a selective serotonin reuptake inhibitor for counteracting depression, has been recently suggested as having a role in prevention of dopaminergic neuronal degeneration in substantia nigra, a hallmark of Parkinson's disease (PD). The pathogenesis of this type of neurological disorders often involves the activation of microglia and associated inflammatory processes. Thus in this study we aimed to understand the role of paroxetine in microglia activation and to elucidate the underlying mechanism(s). METHODS: BV2 and primary microglial cells were pretreated with paroxetine and stimulated with lipopolysaccharide (LPS). Cells were assessed for the responses of pro-inflammatory mediator and cytokines, and the related signaling pathways were evaluated and analyzed in BV2 cells. RESULTS: Paroxetine significantly inhibited LPS-induced production of nitric oxide (NO) and pro-inflammatory cytokines such as TNF-α and IL-1ß. Further analysis showed inducible nitric oxide synthase (iNOS) and mRNA expression of TNF-α and IL-1ß were attenuated by paroxetine pretreatment. Analyses in signaling pathways demonstrated that paroxetine led to suppression of LPS-induced JNK1/2 activation and baseline ERK1/2 activity, but had little effect on the activation of p38 and p65/NF-κB. Interference with specific inhibitors revealed that paroxetine-mediated suppression of NO production was via JNK1/2 pathway while the cytokine suppression was via both JNK1/2 and ERK1/2 pathways. Furthermore, conditioned media culture showed that paroxetine suppressed the microglia-mediated neurotoxicity. CONCLUSIONS: Paroxetine inhibits LPS-stimulated microglia activation through collective regulation of JNK1/2 and ERK1/2 signaling. Our results indicate a potential role of paroxetine in neuroprotection via its anti-neuroinflammatory effect besides targeting for depression.

Development of a core collection for ramie by heuristic search based on SSR markers.

There are more than 2000 ramie germplasms in the National Ramie Germplasm Nursery affiliated with the Institute of Bast Fiber Crops, Chinese Academy of Agricultural Science, China. As it is difficult to perform effective conservation, management, evaluation, and utilization of redundant genetic resources, it is necessary to construct a core collection by using molecular markers. In this study, a core collection of ramie consisting of 22 germplasms was constructed from 108 accessions by heuristic search based on 21 Simple Sequence Repeat (SSR) marker combinations. The results showed that there is a poor relationship between the core collection and the geographic distribution. The number of amplification bands for the core collection was the same as that for the entire collection. Shannon's index for three of the SSR primers (14%) and Nei's index for nine of the SSR primers (19%) were lower in the core collection than in the entire collection. The true core collection had wider genetic diversity compared with the random core collection. Collectively, the core collection constructed in this study is reliable and represents the genetic diversity of all the 108 accessions.

All-potassium channel CRISPR screening reveals a lysine-specific pathway of insulin secretion.

OBJECTIVE: Genome-scale CRISPR-Cas9 knockout coupled with single-cell RNA sequencing (scRNA-seq) has been used to identify function-related genes. However, this method may knock out too many genes, leading to low efficiency in finding genes of interest. Insulin secretion is controlled by several electrophysiological events, including fluxes of KATP depolarization and K+ repolarization. It is well known that glucose stimulates insulin secretion from pancreatic ß-cells, mainly via the KATP depolarization channel, but whether other nutrients directly regulate the repolarization K+ channel to promote insulin secretion is unknown. METHODS: We used a system involving CRISPR-Cas9-mediated knockout of all 83 K+ channels and scRNA-seq in a pancreatic ß cell line to identify genes associated with insulin secretion. RESULTS: The expression levels of insulin genes were significantly increased after all-K+ channel knockout. Furthermore, Kcnb1 and Kcnh6 were the two most important repolarization K+ channels for the increase in high-glucose-dependent insulin secretion that occurred upon application of specific inhibitors of the channels. Kcnh6 currents, but not Kcnb1 currents, were reduced by one of the amino acids, lysine, in both transfected cells, primary cells and mice with ß-cell-specific deletion of Kcnh6. CONCLUSIONS: Our function-related CRISPR screen with scRNA-seq identifies Kcnh6 as a lysine-specific channel.

Establishment and application of a reverse dot blot assay for 13 mutations of hearing-loss genes in primary hospitals in China.

Background: Hearing loss is a common sensorineural dysfunction with a high incidence in China. Although genetic factors are important causes of hearing loss, hearing-related gene detection has not been widely adopted in China. Objective: Establishing a rapid and efficient method to simultaneously detect hotspot hearing loss gene mutations. Methods: A reverse dot blot assay combined with a flow-through hybridization technique was developed for the simultaneous detection of 13 hotspot mutations of 4 hearing loss-related genes including GJB2, GJB3, SLC26A4, and the mitochondrial gene MT-RNR1. This method involved PCR amplification systems and a hybridization platform. Results: The technique can detect 13 hotspot mutations of 4 hearing loss-related genes. And a total of 213 blood samples were used to evaluate the availability of this method. Discussion: Our reverse dot blot assay was a simple, rapid, accurate, and cost-effective method to identify hotspot mutations of 4 hearing loss-related genes in a Chinese population.

Molecular epidemiological survey of hemoglobinopathies in the Wuxi region of Jiangsu Province, eastern China.

In order to determine the prevalence and molecular characterization of hemoglobinopathies in the Wuxi region of Jiangsu Province in the People's Republic of China (PRC), a total of 10,297 healthy people selected from a regional hospital were screened. Hemoglobin (Hb) electrophoresis, complete blood cell (CBC) count, polymerase chain reaction (PCR), DNA sequencing, reverse dot-blot and multiplex ligation-dependent probe amplification (MLPA) were used to detect Hb variants, thalassemias and hereditary persistence of fetal Hb (HPFH). Two thousand and twenty-one adult subjects were screened for thalassemia, five cases were identified as α-thalassemia (α-thal) carriers including three cases of the -α(3.7) (rightward) deletion, one case of the - -(SEA) deletion and one case of ß-thal [IVS-II-654 (C>T), (HBB: c.316-197C>T)]. The incidence of Hb variants, thalassemia and HPFH/δß-thal were 0.136% (14/10,297), 0.25% (5/2021) and 0.0001% (1/10,297), respectively. Eight genotypes of Hb variants were found, including Hb E [ß26(B8)Glu→Lys, GAG>AAG; HBB: c.79G>A], Hb J-Bangkok [ß56(D7)Gly→Asp (GGC>GAC); HBB; c.170G>A], Hb G-Coushatta [ß22(4)Glu→Ala (GAA>GCA); HBB: c.68A>C], Hb Queens [α34(B15)Leu→Arg (CTG>CGG) (α2 or α1); HBA2: c.104T>G (or HBA1)], Hb I [α16(A14)Lys→Glu, AAG>GAG (α1); HBA1: c.49A>G], Hb Beijing [α16(A14)Lys→Asn (AAG>AAC or AAT) (α2 or α1); HBA2: c.51G>C (or HBA1) or 51G>T (or HBA1)], Hb Ube-2 [α68(E17)Asn→Asp (AAC>GAC) (α2 or α1); HBA2: c.205A>G (or HBA1)] and Hb G-Taipei [ß22(B4)Glu→Gly (GAA>GGA); HBB: c.68A>G]. A Sicilian δß(0)-thal, identified for the first time in Asia, was also found in this survey.

Development and evaluation of a reverse dot blot assay for the simultaneous detection of common alpha and beta thalassemia in Chinese.

Thalassemia is the commonest inherited autosomal recessive disorders of hemoglobin in southern China. We developed and evaluated a reverse dot blot (RDB) assay combined with flow-through hybridization technology platform for the rapid and simultaneous identification of 5 types of α-thalassemia and 16 types of ß-thalassemia common in Chinese. Reliable genotyping of wild-type and thalassemic genomic DNA samples was achieved by means of a gene chip on which allele-specific oligonucleotide probes were immobilized on a nylon membrane. This method involved two multiplex PCR amplification systems of α-thalassemia and ß-thalassemia and one time of hybridization. The whole procedure starting from blood sampling to the identification of thalassemia genotype required less than 4h. The diagnostic reliability of this reverse dot blot assay was evaluated on 427 samples (387 cases of thalassemia and 40 healthy persons) by using direct DNA sequence analysis and gap-PCR in a blind study. These samples included 377 cases of blood, 7 cases of amniotic fluid, 18 cases of chorionic villus, and 25 cases of cord blood. The RDB gene chip was in complete concordance with the reference method. The reverse dot blot assay was a simple, rapid, accurate, and cost-effective method to identify common thalassemia genotypes in the Chinese population.

Association Analysis Between HLA-DQA1 Loci and Neuromyelitis Optica Spectrum Disorder in a Han Chinese Population.

BACKGROUND: Genome-wide association studies for neuromyelitis optica spectrum disorder (NMOSD) have established an association between HLA-DQ alpha 1 (DQA1) and risk for NMOSD. Though ethnicity is generally considered a major influencing factor in genetic analyses, little is known regarding the association of HLA-DQA1 polymorphisms with NMOSD in the Han population, especially the single-nucleotide polymorphisms (SNPs) at HLA-DQA1 . METHODS: We genotyped SNP at loci rs28383224 in a case-control study consisting of 137 subjects (51 patients with NMOSD and 86 unrelated controls were recruited) of Han ethnicity. Logistic regression was used to test the association of SNP with NMOSD susceptibility, the sex and age were adjusted, odds ratios and 95% confidence intervals were estimated. RESULTS: The rs28383224 polymorphism and susceptibility to NMOSD were not statistically associated ( P >0.05) in the Han population in the current study. No significant difference was found in allelic frequencies or genotypic distributions among different subsets of NMOSD patients ( P >0.05). CONCLUSION: In the current study, there is no evidence that polymorphism of rs28383224 in the HLA-DQA1 gene is associated with the risk of NMOSD in the Han Chinese population.

Cisapride induced hypoglycemia via the KCNH6 potassium channel.

Mutations in KCNH6 has been proved to cause hypoinsulinemia and diabetes in human and mice. Cisapride is a stomach-intestinal motility drug used to treat gastrointestinal dysfunction. Cisapride has been reported to be a potential inhibitor of the KCNH family, but it remained unclear whether cisapride inhibited KCNH6. Here, we discovered the role of cisapride on glucose metabolism, focusing on the KCNH6 potassium channel protein. Cisapride reduced blood glucose level and increased serum insulin secretion in wild-type (WT) mice fed standard normal chow/a high-fat diet or in db/db mice, especially when combined with tolbutamide. This effect was much stronger after 4 weeks of intraperitoneal injection. Whole-cell patch-clamp showed that cisapride inhibited KCNH6 currents in transfected HEK293 cells in a concentration-dependent manner. Cisapride induced an increased insulin secretion through the disruption of intracellular calcium homeostasis in a rat pancreatic ß-cell line, INS-1E. Further experiments revealed that cisapride did not decrease blood glucose or increase serum insulin in KCNH6 ß-cell knockout (Kcnh6-ß-KO) mice when compared with WT mice. Cisapride also ameliorated glucose-stimulated insulin secretion (GSIS) in response to high glucose in WT but not Kcnh6-ß-KO mice. Thus, our data reveal a novel way for the effect of KCNH6 in cisapride-induced hypoglycemia.

KCNH6 Enhanced Hepatic Glucose Metabolism through Mitochondrial Ca2+ Regulation and Oxidative Stress Inhibition.

KCNH6 has been proven to affect glucose metabolism and insulin secretion both in humans and mice. Further study revealed that Kcnh6 knockout (KO) mice showed impaired glucose tolerance. However, the precise function of KCNH6 in the liver remains unknown. Mitochondria have been suggested to maintain intracellular Ca2+ homeostasis; ROS generation and defective mitochondria can cause glucose metabolism disorders, including type 2 diabetes (T2D). Here, we found that Kcnh6 attenuated glucose metabolism disorders by decreasing PEPCK and G6pase abundance and induced Glut2 and IRS2 expression. Overexpression of Kcnh6 increased hepatic glucose uptake and glycogen synthesis. Kcnh6 attenuated intracellular and mitochondrial calcium levels in primary hepatocytes and reduced intracellular ROS and mitochondrial superoxide production. Kcnh6 suppressed oxidative stress by inhibiting mitochondrial pathway activation and NADPH oxidase expression. Experiments demonstrated that Kcnh6 expression improved hepatic glucose metabolism disorder through the c-Jun N-terminal kinase and p38MAPK signaling pathways. These results were confirmed by experiments evaluating the extent to which forced Kcnh6 expression rescued metabolic disorder in KO mice. In conclusion, KCNH6 enhanced hepatic glucose metabolism by regulating mitochondrial Ca2+ levels and inhibiting oxidative stress. As liver glucose metabolism is key to T2D, understanding KCNH6 functions may provide new insights into the causes of diabetes.

Clinical characteristics and ABCC2 genotype in Dubin-Johnson syndrome: A case report and review of the literature.

BACKGROUND: Dubin-Johnson syndrome (DJS) is a benign autosomal recessive liver disease involving mutations of the ABCC2 gene. It is characterized by chronic or intermittent conjugated hyperbilirubinemia, with chronic idiopathic jaundice as the main clinical manifestation. Genetic alterations of the ABCC2 gene are commonly used for diagnosing DJS; however, the causative ABCC2 point mutation in Chinese patients remains unknown. Research on ABCC2 mutations in Chinese DJS patients is extremely rare, and the diagnosis of DJS remains limited. The routine analysis of ABCC2 mutations is helpful for the diagnosis of DJS. Here, we report the clinical characteristics and ABCC2 genotype of an adult female DJS patient. This article is to expound the discovery of more potentially pathogenic ABCC2 variants will that contribute to DJS identification. CASE SUMMARY: This study investigated a woman referred for DJS and involved clinical and genetic analyses. ABCC2 mutations were identified by next-generation sequencing (NGS). The patient showed intermittent jaundice and conjugated hyper-bilirubinemia. Histopathological examinations were consistent with the typical phenotype of DJS. Genetic diagnostic analysis revealed an ABCC2 genotype exhibiting a pathogenic variant, namely c.2443C>T (p.Arg815*), which has not been reported previously in the domestic or foreign literature. CONCLUSION: Pathogenic ABCC2 mutations play an important role in the diagnosis of DJS, especially in patients with atypical presentations. Currently, NGS is used in the routine analysis of DJS cases and such tests of further cases will better illuminate the relationship between various genotypes and phenotypes of DJS.