Understanding the genetic factors of diabetes is essential for addressing the global increase in type 2 diabetes. HNF1A mutations cause a monogenic form of diabetes called maturity-onset diabetes of ...the young (MODY), and HNF1A single-nucleotide polymorphisms are associated with the development of type 2 diabetes. Numerous studies have been conducted, mainly using genetically modified mice, to explore the molecular basis for the development of diabetes caused by HNF1A mutations, and to reveal the roles of HNF1A in multiple organs, including insulin secretion from pancreatic beta cells, lipid metabolism and protein synthesis in the liver, and urinary glucose reabsorption in the kidneys. Recent studies using human stem cells that mimic MODY have provided new insights into beta cell dysfunction. In this article, we discuss the involvement of HNF1A in beta cell dysfunction by reviewing previous studies using genetically modified mice and recent findings in human stem cell-derived beta cells.
Pathological excess of fibroblast growth factor 23 (FGF23) causes mineral and bone disorders. However, the causality of FGF23 in the development of osteoporosis remains unknown. Whether FGF23 has ...systemic effects on cardiometabolic disorders beyond regulating mineral metabolism is also controversial. In this study, we investigated the causal effect of FGF23 on osteoporosis and cardiometabolic disorders using Mendelian randomization (MR) analysis. Summary statistics for single-nucleotide polymorphisms with traits of interest were obtained from the relevant genome-wide association studies. As a result, FGF23 was found to be inversely associated with femoral neck-BMD (odds ratio OR 0.682, 95% confidence interval CI 0.546–0.853, p = 8e-04) and heel estimated BMD (eBMD) (OR 0.898, 95%CI 0.820–0.985, p = 0.022) in the inverse-variance-weighted analysis, but not lumbar spine-BMD and fractures. The results were supported by the weighted-median analysis, and there was no evidence of pleiotropy in the MR-Egger analysis. FGF23 was associated with FN-BMD and eBMD after adjustment for estimated glomerular filtration rate, height, and body mass index in multivariable MR analysis. On the other hand, there was no association between FGF23 and cardiometabolic traits including cardio artery disease, brachial-ankle pulse wave velocity, intima-media thickness of carotid arteries, systolic and diastolic blood pressure, fasting glucose, high and low-density lipoprotein cholesterol, and triglycerides. Therefore, this MR study established that FGF23 was involved in bone loss and, in contrast, was not involved in cardiometabolic disorders. Our findings provide important insights into the role of FGF23 in the pathogenesis of osteoporosis and cardiometabolic disorders.
•Role of FGF23 in the development of osteoporosis remains unknown.•Whether FGF23 has systemic effects on cardiometabolic disorders is controversial.•Mendelian randomization (MR) analysis is able to infer causal association.•This MR study found that FGF23 was associated with bone loss.•In contrast, FGF23 was not associated with cardiometabolic disorders.
Primary aldosteronism (PA) is associated with an increased risk of cardiometabolic diseases, especially in unilateral subtype. Despite its high prevalence, the case detection rate of PA is limited, ...partly because of no clinical models available in general practice to identify patients highly suspicious of unilateral subtype of PA, who should be referred to specialized centers. The aim of this retrospective cross-sectional study was to develop a predictive model for subtype diagnosis of PA based on machine learning methods using clinical data available in general practice. Overall, 91 patients with unilateral and 138 patients with bilateral PA were randomly assigned to the training and test cohorts. Four supervised machine learning classifiers; logistic regression, support vector machines, random forests (RF), and gradient boosting decision trees, were used to develop predictive models from 21 clinical variables. The accuracy and the area under the receiver operating characteristic curve (AUC) for predicting of subtype diagnosis of PA in the test cohort were compared among the optimized classifiers. Of the four classifiers, the accuracy and AUC were highest in RF, with 95.7% and 0.990, respectively. Serum potassium, plasma aldosterone, and serum sodium levels were highlighted as important variables in this model. For feature-selected RF with the three variables, the accuracy and AUC were 89.1% and 0.950, respectively. With an independent external PA cohort, we confirmed a similar accuracy for feature-selected RF (accuracy: 85.1%). Machine learning models developed using blood test can help predict subtype diagnosis of PA in general practice.
The Cre-loxP strategy for tissue-specific gene inactivation has become a widely employed tool in several research studies. Conversely, inadequate breeding and genotyping without considering the ...potential for non-specific Cre-recombinase expression may lead to misinterpretations of results. Nestin-Cre transgenic mice, widely used for the selective deletion of genes in neurons, have been observed to have an incidence of Cre-line germline recombination. In this study, we attempted to generate neuron-specific Glucagon-like peptide 1 receptor (Glp1r) knock-out mice by crossing mice harboring the Nestin-Cre transgene with mice harboring the Glp1r gene modified with loxP insertion, in order to elucidate the role of Glp1r signaling in the nervous system. Surprisingly, during this breeding process, we discovered that the null allele emerged in the offspring irrespective of the presence or absence of the Nestin-Cre transgene, with a high probability of occurrence (93.6%). To elucidate the cause of this null allele, we conducted breeding experiments between mice carrying the heterozygous Glp1r null allele but lacking the Nestin-Cre transgene. We confirmed that the null allele was inherited by the offspring independently of the Nestin-Cre transgene. Furthermore, we assessed the gene expression, protein expression, and phenotype of mice carrying the homozygous Glp1r null allele generated from the aforementioned breeding, thereby confirming that the null allele indeed caused a global knock-out of Glp1r. These findings suggest that the null allele in the NestinCre-Glp1r floxed breeding arose due to germline recombination. Moreover, we demonstrated the possibility that germline recombination may occur not only during the spermatogenesis at testis but also during epididymal sperm maturation. The striking frequency of germline recombination in the Nestin-Cre driver underscores the necessity for caution when implementing precise breeding strategies and employing suitable genotyping methods.
Aims/hypothesis
Mitochondria are highly dynamic organelles continuously undergoing fission and fusion, referred to as mitochondrial dynamics, to adapt to nutritional demands. Evidence suggests that ...impaired mitochondrial dynamics leads to metabolic abnormalities such as non-alcoholic steatohepatitis (NASH) phenotypes. However, how mitochondrial dynamics are involved in the development of NASH is poorly understood. This study aimed to elucidate the role of mitochondrial fission factor (MFF) in the development of NASH.
Methods
We created mice with hepatocyte-specific deletion of MFF (
Mff
LiKO).
Mff
LiKO mice fed normal chow diet (NCD) or high-fat diet (HFD) were evaluated for metabolic variables and their livers were examined by histological analysis. To elucidate the mechanism of development of NASH, we examined the expression of genes related to endoplasmic reticulum (ER) stress and lipid metabolism, and the secretion of triacylglycerol (TG) using the liver and primary hepatocytes isolated from
Mff
LiKO and control mice.
Results
Mff
LiKO mice showed aberrant mitochondrial morphologies with no obvious NASH phenotypes during NCD, while they developed full-blown NASH phenotypes in response to HFD. Expression of genes related to ER stress was markedly upregulated in the liver from
Mff
LiKO mice. In addition, expression of genes related to hepatic TG secretion was downregulated, with reduced hepatic TG secretion in
Mff
LiKO mice in vivo and in primary cultures of MFF-deficient hepatocytes in vitro. Furthermore, thapsigargin-induced ER stress suppressed TG secretion in primary hepatocytes isolated from control mice.
Conclusions/interpretation
We demonstrated that ablation of MFF in liver provoked ER stress and reduced hepatic TG secretion in vivo and in vitro. Moreover,
Mff
LiKO mice were more susceptible to HFD-induced NASH phenotype than control mice, partly because of ER stress-induced apoptosis of hepatocytes and suppression of TG secretion from hepatocytes. This study provides evidence for the role of mitochondrial fission in the development of NASH.
Graphical abstract
Angiopoietin-like protein (ANGPTL)8 is a liver- and adipocyte-derived protein that controls plasma triglyceride (TG) levels. Most animal studies have used mouse models. Here, we generated an Angptl8 ...KO rat model using a clustered regulatory interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) (CRISPR/Cas9) system to clarify the roles of ANGPTL8 in glucose and lipid metabolism. Compared with WT rats, Angptl8 KO rats had lower body weight and fat content, associated with impaired lipogenesis in adipocytes; no differences existed between the groups in food intake or rectal temperature. Plasma TG levels in both the fasted and refed states were significantly lower in KO than in WT rats, and an oral fat tolerance test showed decreased plasma TG excursion in Angptl8 KO rats. Higher levels of lipase activity in the heart and greater expression of genes related to β-oxidation in heart and skeletal muscle were observed in Angptl8 KO rats. However, there were no significant differences between KO and WT rats in glucose metabolism or the histology of pancreatic β-cells on both standard and high-fat diets. In conclusion, we demonstrated that Angptl8 KO in rats resulted in lower body weight and plasma TG levels without affecting glucose metabolism. ANGPTL8 might be an important therapeutic target for obesity and dyslipidemia.
There has been a concern that sodium-glucose cotransporter 2 (SGLT2) inhibitors could reduce skeletal muscle mass and function. Here, we examine the effect of canagliflozin (CANA), an SGLT2 ...inhibitor, on slow and fast muscles from nondiabetic C57BL/6J mice. In this study, mice were fed with or without CANA under ad libitum feeding, and then evaluated for metabolic valuables as well as slow and fast muscle mass and function. We also examined the effect of CANA on gene expressions and metabolites in slow and fast muscles. During SGLT2 inhibition, fast muscle function is increased, as accompanied by increased food intake, whereas slow muscle function is unaffected, although slow and fast muscle mass is maintained. When the amount of food in CANA-treated mice is adjusted to that in vehicle-treated mice, fast muscle mass and function are reduced, but slow muscle was unaffected during SGLT2 inhibition. In metabolome analysis, glycolytic metabolites and ATP are increased in fast muscle, whereas glycolytic metabolites are reduced but ATP is maintained in slow muscle during SGLT2 inhibition. Amino acids and free fatty acids are increased in slow muscle, but unchanged in fast muscle during SGLT2 inhibition. The metabolic effects on slow and fast muscles are exaggerated when food intake is restricted. This study demonstrates the differential effects of an SGLT2 inhibitor on slow and fast muscles independent of impaired glucose metabolism, thereby providing new insights into how they should be used in patients with diabetes, who are at a high risk of sarcopenia.
Pheochromocytoma (PHEO) and paraganglioma (PGL) (PHEO and PGL: PPGLs), catecholamine-producing tumors, represent an emerging cause of secondary osteoporosis. However, despite decreased bone mineral ...density (BMD), vertebral fracture (VF) is not associated with BMD in PPGLs.
To evaluate whether deteriorated bone quality is involved in the development of osteoporosis in PPGLs.
Trabecular bone score (TBS), used to assess trabecular bone quality, was examined in 56 patients with PPGLs and 52 with non-functional adrenal tumors (AT). Radiograph of the spine was carried out in 35 patients with PPGLs, and TBS was analyzed in 18 patients with PPGLs at follow-up.
TBS and BMD at the lumbar spine in patients with PPGLs with and without VF.
PPGLs had a lower TBS (n = 56, 1.338 1.294–1.420) than non-functional AT (n = 52, 1.394 1.342–1.444; p = 0.033). Among those with PPGLs, patients with VF (n = 14, 1.314 1.289–1.346) had a lower TBS than those without VF (n = 21, 1.383 1.324–1.426; p = 0.046), despite no significant difference in BMD at the lumbar spine between the two groups (p = 0.501). An optimal cut-off level of TBS for diagnosing VF in PPGLs was 1.323, and its area under the curve was 0.702. The severity of catecholamine excess and maximal size of tumor were associated with decreased TBS in PPGLs patients (p = 0.016 and p = 0.020, respectively). Surgical resection of PPGLs improved TBS at follow-up, with 2.5% increase (p = 0.007).
This study provides evidence for the importance of deteriorated bone quality rather than decreased bone mass in the development of VF in PPGLs.
Display omitted
•VF is associated with decreased TBS rather than decreased BMD in PPGLs.•A cut-off of TBS for detecting VF in PPGLs is comparable to that in general.•Surgical resection of the PPGLs improves TBS beyond the cut-off.
Since respiratory sample collection is an uncomfortable experience, simultaneous detection of pathogens with a single swab is preferable. We prospectively evaluated the clinical performance of a ...newly developed antigen test QuickNavi-Flu+COVID19 Ag (Denka Co., Ltd., Tokyo, Japan) which can detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses at the same time with a single testing device.
We included those who were suspected of contracting coronavirus disease 2019 (COVID-19) and were referred to a PCR center at Ibaraki prefecture in Japan, between August 2, 2021 to September 13, 2021, when the variant carrying L452R spike mutation of SARS-CoV-2 were prevalent. Additional nasopharyngeal samples and anterior nasal samples were obtained for the antigen test and were compared with a reference real-time reverse transcription PCR (RT-PCR) using nasopharyngeal samples.
In total, 1510 nasopharyngeal samples and 862 anterior nasal samples were evaluated. During the study period, influenza viruses were not detected by QuickNavi-Flu+COVID19 Ag and reference real-time RT-PCR. For SARS-CoV-2 detection in nasopharyngeal samples, the sensitivity and specificity of the antigen test were 80.9% and 99.8%, respectively. The sensitivity and specificity using anterior nasal samples were 67.8% and 100%, respectively. In symptomatic cases, the sensitivities increased to 88.3% with nasopharyngeal samples and 73.7% with anterior nasal samples. There were three cases of discrepant results between the antigen test and the real-time RT-PCR. All of them were positive with the antigen test but negative with the real-time RT-PCR in SARS-CoV-2 detection.
A combo kit, QuickNavi-Flu+COVID19 Ag, showed an acceptable sensitivity and sufficient specificity for SARS-CoV-2 detection, especially using nasopharyngeal sample collected from symptomatic patients.
Pheochromocytoma (PHEO) and paraganglioma (PGL) (PHEO and PGL: PPGLs) are catecholamine-producing neuroendocrine tumors, which are known to be associated with low bone mineral density (BMD). However, ...it remains unknown whether PPGLs are associated with high prevalence of osteoporotic fracture and if so, whether their surgical resection improves BMD has been addressed.
To evaluate the risk of vertebral fracture (VF) in PPGLs and the improvement of BMD after surgery.
A retrospective cross-sectional study in a single referral center.
This study included the following patients: 1) 49 patients with PPGLs and 61 patients with non-functional AT who were examined radiograph of the spine, 2) 23 patients with PPGLs who were examined BMD at follow-up.
1) The prevalence of VF was evaluated between PPGLs and non-functional AT. 2) In PPGLs, BMD was evaluated at baseline and after surgery.
PPGLs had a higher prevalence of VF (43% 21/49) than non-functional AT (16% 10/61; p = 0.002). PPGLs were associated with VF after adjusting for age and sex (odds ratio, 4.47; 95% confidence interval, 1.76–11.3; p = 0.001). In PPGLs, BMD at the lumber spine was improved (before: 0.855 ± 0.198 g/cm2, after: 0.888 ± 0.169 g/cm2, mean of the difference: 0.032 g/cm2, p = 0.026), with 3.8% increase.
This study demonstrates that PPGLs was associated with VF and that their surgical resection contributes to the improvement of BMD in the trabecular bone. These observations support the notion that PPGLs are an emerging cause of secondary osteoporosis.
•PPGLs are associated with vertebral fracture.•BMD improves after surgery.•PPGLs could be an emerging cause of secondary osteoporosis.
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