From stem cells to pancreatic β-cells: strategies, applications, and potential treatments for diabetes

Loss and functional failure of pancreatic β-cells results in disruption of glucose homeostasis and progression of diabetes. Although whole pancreas or pancreatic islet transplantation serves as a promising approach for β-cell replenishment and diabetes therapy, the severe scarcity of donor islets makes it unattainable for most diabetic patients. Stem cells, particularly induced pluripotent stem cells (iPSCs), are promising for the treatment of diabetes owing to their self-renewal capacity and ability to differentiate into functional β-cells. In this review, we first introduce the development of functional β-cells and their heterogeneity and then turn to highlight recent advances in the generation of β-cells from stem cells and their potential applications in disease modeling, drug discovery and clinical therapy. Finally, we have discussed the current challenges in developing stem cell-based therapeutic strategies for improving the treatment of diabetes. Although some significant technical hurdles remain, stem cells offer great hope for patients with diabetes and will certainly transform future clinical practice.

Pancreatic β-cell failure, clinical implications, and therapeutic strategies in type 2 diabetes

ABSTRACT

Pancreatic β-cell failure due to a reduction in function and mass has been defined as a primary contributor to the progression of type 2 diabetes (T2D). Reserving insulin-producing β-cells and hence restoring insulin production are gaining attention in translational diabetes research, and β-cell replenishment has been the main focus for diabetes treatment. Significant findings in β-cell proliferation, transdifferentiation, pluripotent stem cell differentiation, and associated small molecules have served as promising strategies to regenerate β-cells. In this review, we summarize current knowledge on the mechanisms implicated in β-cell dynamic processes under physiological and diabetic conditions, in which genetic factors, age-related alterations, metabolic stresses, and compromised identity are critical factors contributing to β-cell failure in T2D. The article also focuses on recent advances in therapeutic strategies for diabetes treatment by promoting β-cell proliferation, inducing non-β-cell transdifferentiation, and reprograming stem cell differentiation. Although a significant challenge remains for each of these strategies, the recognition of the mechanisms responsible for β-cell development and mature endocrine cell plasticity and remarkable advances in the generation of exogenous β-cells from stem cells and single-cell studies pave the way for developing potential approaches to cure diabetes.

JunB condensation attenuates vascular endothelial damage under hyperglycemic condition

Endothelial damage is the initial and crucial factor in the occurrence and development of vascular complications in diabetic patients, contributing to morbidity and mortality. Although hyperglycemia has been identified as a damaging effector, the detailed mechanisms remain elusive. In this study, identified by ATAC-seq and RNA-seq, JunB reverses the inhibition of proliferation and the promotion of apoptosis in human umbilical vein endothelial cells treated with high glucose, mainly through the cell cycle and p53 signaling pathways. Furthermore, JunB undergoes phase separation in the nucleus and in vitro, mediated by its intrinsic disordered region and DNA-binding domain. Nuclear localization and condensation behaviors are required for JunB-mediated proliferation and apoptosis. Thus, our study uncovers the roles of JunB and its coacervation in repairing vascular endothelial damage caused by high glucose, elucidating the involvement of phase separation in diabetes and diabetic endothelial dysfunction.

Liraglutide ameliorates hepatic steatosis via retinoic acid receptor-related orphan receptor α-mediated autophagy pathway

Liraglutide, an analog of human glucagon-like peptide-1 (GLP-1), has been found to improve hepatic steatosis in clinical practice. However, the underlying mechanism remains to be fully defined. Increasing evidence suggests that retinoic acid receptor-related orphan receptor α (RORα) is involved in hepatic lipid accumulation. In the current study, we investigated whether the ameliorating impact of liraglutide on lipid-induced hepatic steatosis is dependent on RORα activity and examined the underlying mechanisms. Cre-loxP-mediated, liver-specific Rorα knockout (Rora LKO) mice, and littermate controls with a Roraloxp/loxp genotype were established. The effects of liraglutide on lipid accumulation were evaluated in mice challenged with a high-fat diet (HFD) for 12 weeks. Moreover, mouse AML12 hepatocytes expressing small interfering RNA (siRNA) of Rora were exposed to palmitic acid to explore the pharmacological mechanism of liraglutide. The results showed that liraglutide treatment significantly alleviated HFD-induced liver steatosis, marked by reduced liver weight and triglyceride accumulation, improved glucose tolerance and serum levels of lipid profiles and aminotransferase. Consistently, liraglutide also ameliorated lipid deposits in a steatotic hepatocyte model in vitro. In addition, liraglutide treatment reversed the HFD-induced downregulation of Rora expression and autophagic activity in mouse liver tissues. However, the beneficial effect of liraglutide on hepatic steatosis was not observed in Rora LKO mice. Mechanistically, the ablation of Rorα in hepatocytes diminished liraglutide-induced autophagosome formation and the fusion of autophagosomes and lysosomes, resulting in weakened autophagic flux activation. Thus, our findings suggest that RORα is essential for the beneficial impact of liraglutide on lipid deposition in hepatocytes and regulates autophagic activity in the underlying mechanism.

Hybrid Immuno-RT for Bulky Tumors: Standard Fractionation with Partial Tumor SBRT

PURPOSE/OBJECTIVE(S)

Bulky tumors remain challenging to be treated. Stereotactic body radiation therapy (SBRT) is effective against radioresistant tumor cells and can induce immunogenic cell death (ICD) that leads to T-cell-mediated antitumor effects. Low-dose radiation (LDRT) can inflame the tumor microenvironment (TME) by recruiting T cells. We designed a novel radiotherapy technique (RT, ERT) whose dose distribution map resembles the "eclipse" by concurrently delivering LDRT to the whole tumor, meanwhile SBRT to only a part of the same tumor. This study examined the safety and efficacy of ERT to bulky lesions with PD-1 inhibitors in mice and patients.

MATERIALS/METHODS

In mice with CT26 colon or LLC1 lung bulky tumors (400 - 500 cm3), the whole tumor was irradiated by LDRT (2 Gy x 3), meanwhile the tumor center was irradiated by SBRT (10 Gy x 3); αPD-1 was given weekly. The dependence of therapeutic effects on CD8+ T cells was determined using depleting antibodies. Frequencies of CD8+ T cells and M1 macrophages (Mφ) were determined by flow cytometry. Multiplex Immunohistochemistry (mIHC) was applied to analyze the number and the location of CD8+ T cells and their subpopulations, as well as the phospho-eIF2α level (the ICD marker) of tumor cells in TME. Patients with advanced lung or liver bulky tumors who failed standard treatment or with oncologic emergencies were treated. Kaplan-Meier method was applied to estimate patients' progression-free survival (PFS) and overall survival (OS).

RESULTS

ERT/αPD-1 is superior to SBRT/αPD-1 or LDRT/αPD-1 in controlling bulky tumors in both mouse models in a CD8+ T-cell dependent manner. In the CT26 model, ERT/αPD-1 resulted in complete tumor regression in 3/11 mice and induced more CD8+ T cells and M1 Mφ in TME compared to other groups. mIHC analysis showed that ERT/αPD-1 induced higher bulk, stem-like (TCF1+ TIM3- PD-1+), and more differentiated (TCF1- TIM3+ PD-1+) CD8+ T cells infiltration into the tumor center and periphery compared to other groups. Compared to untreated or LDRT-treated tumor centers, tumor centers irradiated with ERT or SBRT showed elevated phospho-eIF2α accompanied by higher dendritic cell infiltration. In total, 39 advanced cancer patients were treated with ERT/αPD-1 or plus chemotherapy. Radiation-induced pneumonitis occurred in 1 of 26 patients receiving thoracic ERT. There were two cases of grade III toxicity associated with PD-1 inhibitors. No toxicity above grade III was observed. The objective response rate was 38.5%. The median PFS was 5.6 months and median OS was not reached at a median follow-up of 11.7 months.

CONCLUSION

ERT/αPD-1 showed superior efficacy in controlling bulky tumor in two mouse models. The hybrid immuno-RT (ERT) combing PD-1 inhibitors was safe and effective in patients with bulky tumors. Further clinical trials in combination with bioimaging to identify the optimal SBRT target region for the bulky tumor are warranted.

Directional atherectomy combined with drug-coated balloon angioplasty for superficial femoral arteriosclerosis obliterans

INTRODUCTION

This study is an analysis of the therapeutic effects of directional atherectomy combined with drug-coated balloon angioplasty (DA+DCB) in treating superficial femoral arteriosclerosis obliterans.

METHODS

Patients in our hospital with superficial femoral arteriosclerosis obliterans who received DA+DCB during the period June 2016 to February 2019 were identified retrospectively. Preoperative demographics, operative details and postoperative follow-up outcomes were analysed statistically.

RESULTS

Between June 2016 and February 2019, 48 patients were enrolled in this retrospective study. The average age of the patients was 66.85 ± 11.28 years; 83.3% of the patients were male. During the procedure, flow-limiting dissection occurred frequently (9/48 patients) and there were six bailout stent implantations owing to flow-limiting dissections. The incidence rate of target artery thrombosis was 4.2% (2/48). There was no vessel perforation, embolism or operation-related death. The technical success rate was estimated at 100%. The mean ankle-brachial index of the patients was 0.54 ± 0.28 before the operation and 0.93 ± 0.13 before discharge (p < 0.0001). The mean follow-up time was 19.6 ± 9.0 months. The primary patency rate was 89.4%, 82.4% and 76.5% at 12, 24 and 36 months. The freedom from target lesion revascularisation (TLR) was 97.9%, 93.8% and 84.4% at 12, 24 and 36 months.

CONCLUSION

The use of DA+DCB showed good clinical benefit for superficial femoral arteriosclerosis obliterans, which had good primary patency and freedom from TLR. Multicentre randomised controlled trials with long-term follow-up are needed.

[Sinogram interpolation combined with unsupervised image-to-image translation network for CT metal artifact correction]

OBJECTIVE

To propose a framework that combines sinogram interpolation with unsupervised image-to-image translation (UNIT) network to correct metal artifacts in CT images.

METHODS

The initially corrected CT image and the prior image without artifacts, which were considered as different elements in two different domains, were input into the image transformation network to obtain the corrected image. Verification experiments were carried out to assess the effectiveness of the proposed method using the simulation data, and PSNR and SSIM were calculated for quantitative evaluation of the performance of the method.

RESULTS

The experiment using the simulation data showed that the proposed method achieved better results for improving image quality as compared with other methods, and the corrected images preserved more details and structures. Compared with ADN algorithm, the proposed algorithm improved the PSNR and SSIM by 2.4449 and 0.0023 when the metal was small, by 5.9942 and 8.8388 for images with large metals, and by 8.8388 and 0.0130 when both small and large metals were present, respectively.

CONCLUSION

The proposed method for metal artifact correction can effectively remove metal artifacts, improve image quality, and preserve more details and structures on CT images.

Nuclear factor-Y mediates pancreatic β-cell compensation by repressing reactive oxygen species-induced apoptosis under metabolic stress

BACKGROUND

Pancreatic β-cells elevate insulin production and secretion through a compensatory mechanism to override insulin resistance under metabolic stress conditions. Deficits in β-cell compensatory capacity result in hyperglycemia and type 2 diabetes (T2D). However, the mechanism in the regulation of β-cell compensative capacity remains elusive. Nuclear factor-Y (NF-Y) is critical for pancreatic islets' homeostasis under physiological conditions, but its role in β-cell compensatory response to insulin resistance in obesity is unclear.

METHODS

In this study, using obese ( ob/ob ) mice with an absence of NF-Y subunit A (NF-YA) in β-cells ( ob , Nf-ya βKO) as well as rat insulinoma cell line (INS1)-based models, we determined whether NF-Y-mediated apoptosis makes an essential contribution to β-cell compensation upon metabolic stress.

RESULTS

Obese animals had markedly augmented NF-Y expression in pancreatic islets. Deletion of β-cell Nf-ya in obese mice worsened glucose intolerance and resulted in β-cell dysfunction, which was attributable to augmented β-cell apoptosis and reactive oxygen species (ROS). Furthermore, primary pancreatic islets from Nf-ya βKO mice were sensitive to palmitate-induced β-cell apoptosis due to mitochondrial impairment and the attenuated antioxidant response, which resulted in the aggravation of phosphorylated c-Jun N-terminal kinase (JNK) and cleaved caspase-3. These detrimental effects were completely relieved by ROS scavenger. Ultimately, forced overexpression of NF-Y in INS1 β-cell line could rescue palmitate-induced β-cell apoptosis, dysfunction, and mitochondrial impairment.

CONCLUSION

Pancreatic NF-Y might be an essential regulator of β-cell compensation under metabolic stress.

The incidence, prevalence, and survival analysis of pancreatic neuroendocrine tumors in the United States

PURPOSE

The incidence of pancreatic neuroendocrine tumors (pNETs) was increasing. The main purpose of this study was to statistically analyze the incidence and prevalence of pNETs and the main risk factors for the prognosis.

METHODS

Based on the Surveillance, Epidemiology, and End Results (SEER) database, with three registries integrated, this study comprehensively displayed the annual age adjust incidence of pNETs from 1975 to 2018, the estimated 20-year limited-duration prevalence, and conducted the univariate and multivariate survival analysis.

RESULTS

The incidence of pNETs has increased to about 1.5 per 100,000 population, and the prevalence has reached about 0.008% with the aged, Grade 1 and nonfunctional tumors accounting for the majority. The average median overall survival (OS), 5-year survival rate, and median disease-free survival (DFS) of pNETs patients from 1975 to 2018 were 85 months, 57.55%, and 220 months, respectively. From 2000 to 2018, the median OS was 94 months, and the 5-year survival rate was 59.94%. In multivariate survival analysis, the greatest risk factor was Grade 3&4 with HR = 3.62 (3.10-4.28), followed by distant stage with HR = 2.77 (2.28-3.36), and aged over 80 years old with HR = 2.26 (1.33-3.83). Surgery was a protective prognostic factor with HR = 0.34 (0.29-0.40).

CONCLUSION

The incidence and prevalence of pNETs were still increasing, but the trend was gradual and aging in recent years. The survival time of pNETs was longer but has not changed much in recent years. The degrees of malignancy, stage, and operation were the most important prognosis factors.

Excimer laser atherectomy combined with drug-coated balloon angioplasty for the treatment of femoropopliteal arteriosclerosis obliterans

INTRODUCTION

It has been reported that excimer laser atherectomy combined with a drug-coated balloon (ELA+DCB) can achieve better results than simple balloon angioplasty, especially for the treatment of femoropopliteal in-stent restenosis. However, reports on the application of ELA+DCB in China for femoropopliteal arteriosclerosis obliterans are lacking. This study focuses on analysing the effectiveness and safety of ELA+DCB.

METHODS

This was a single-centre retrospective study that enrolled patients from November 2016 to January 2019 who had femoropopliteal arteriosclerosis obliterans treated by ELA+DCB. Preoperative demographics, operative details and postoperative follow-up outcomes were analysed statistically.

RESULTS

There were 43 patients with an average patient age of 68.0±8.6 years; 79.1% were male. In 30 cases, the lesions were de novo and the others were in-stent restenosis (ISR). During the procedure, flow-limiting dissection (48.8%) was the main adverse event and there were 17 bailout stent implantations due to dissection. Mean (±sd) ankle-brachial index (ABI) in the patients was 0.42±0.31 before the operation and 0.83±0.13 before discharge. The mean (±sd) follow-up time was 29.35±9.71 months. The primary patency rate was 66.8%, 64.3% and 60.9% at 12, 24 and 36 months. Freedom from target lesion revascularisation (TLR) was 85.7%, 80.7% and 75.3% at 12, 24 and 36 months. Rutherford categories also greatly improved during follow-up. Overall mortality was 6.9% (3/48), and no deaths were related to the intervention.

CONCLUSION

The use of ELA+DCB had good clinical benefit for femoropopliteal arteriosclerosis obliterans, which had good primary patency and freedom from TLR, although intraoperative complications still required attention. Multicentre randomised controlled trials with long-term follow-up are needed.

Symptom burden, psychological distress, and symptom management status in hospitalized patients with advanced cancer: a multicenter study in China

BACKGROUND

The management of physical symptoms and psychological distress of cancer patients is an important component of cancer care. The purpose of this study was to evaluate the symptom burden, psychological distress, and management status of hospitalized patients with advanced cancer in China and explore the potential influencing factors of undertreatment and non-treatment of symptoms.

PATIENTS AND METHODS

A total of 2930 hospitalized patients with advanced cancer (top six types of cancer in China) were recruited from 10 centers all over China. Patient-reported MD Anderson Symptom Inventory, Hospital Anxiety and Depression Scale (HADS), and Patient Health Questionnaire-9 (PHQ-9) scales and symptom management-related information were collected and linked with the patient's clinical data. The proportion of patients reporting moderate-to-severe (MS) symptoms and whether they were currently well managed were examined. Multivariable logistic regression models were applied to explore the factors correlated to undertreatment and non-treatment of symptoms.

RESULTS

About 27% of patients reported over three MS symptoms, 16% reported over five, and 9% reported over seven. Regarding psychological distress, the prevalence of HADS-anxiety was 29% and that of PHQ-9 depression was 11%. Sixty-one percent of patients have at least one MS symptom without any treatment. Sex [odds ratio (OR) = 2.238, 95% confidence interval (95% CI) 1.502-3.336], Eastern Cooperative Oncology Group (ECOG; OR = 0.404, 95% CI 0.241-0.676), and whether currently undergoing anticancer treatment (OR = 0.667, 95% CI 0.503-0.886) are the main factors correlated with the undertreatment of symptoms. Age (OR = 1.972, 95% CI 1.263-3.336), sex (OR = 0.626, 95% CI 0.414-0.948), ECOG (OR = 0.266, 95% CI 0.175-0.403), whether currently undergoing anticancer treatment (OR = 0.356, 95% CI 0.249-0.509), and comorbidity (OR = 0.713, 95% CI 0.526-0.966) are the main factors correlated with the non-treatment of symptoms.

CONCLUSIONS

This study shows that hospitalized patients with advanced cancer had a variety of physical and psychological symptoms but lacked adequate management and suggests that a complete symptom screening and management system is needed to deal with this complex problem.

[Relationship between body mass index and sexual development in Chinese children]

Objective: To investigate the relationship between body mass index (BMI) and sexual development in Chinese children. Methods: A nationwide multicenter and population-based large cross-sectional study was conducted in 13 provinces, autonomous regions and municipalities of China from January 2017 to December 2018. Data on sex, age, height, weight were collected, BMI was calculated and sexual characteristics were analyzed. The subjects were divided into four groups based on age, including ages 3-<6 years, 6-<10 years, 10-<15 years and 15-<18 years. Multiple Logistic regression models were used for evaluating the associations of BMI with sexual development in children. Dichotomous Logistic regression was used to compare the differences in the distribution of early and non-early puberty among normal weight, overweight and obese groups. Curves were drawn to analyze the relationship between the percentage of early puberty and BMI distribution in girls and boys at different Tanner stages. Results: A total of 208 179 healthy children (96 471 girls and 111 708 boys) were enrolled in this study. The OR values of B2, B3 and B4+ in overweight girls were 1.72 (95%CI: 1.56-1.89), 3.19 (95%CI: 2.86-3.57), 7.14 (95%CI: 6.33-8.05) and in obese girls were 2.05 (95%CI: 1.88-2.24), 4.98 (95%CI: 4.49-5.53), 11.21 (95%CI: 9.98-12.59), respectively; while the OR values of G2, G3, G4+ in overweight boys were 1.27 (95%CI: 1.17-1.38), 1.52 (95%CI: 1.36-1.70), 1.88 (95%CI: 1.66-2.14) and in obese boys were 1.27 (95%CI: 1.17-1.37), 1.59 (95%CI: 1.43-1.78), and 1.93 (95%CI: 1.70-2.18) (compared with normal weight Tanner 1 group,all P<0.01). Analysis in different age groups found that OR values of obese girls at B2 stage and boys at G2 stage were 2.02 (95%CI: 1.06-3.86) and 2.32 (95%CI:1.05-5.12) in preschool children aged 3-<6 years, respectively (both P<0.05). And in the age group of 6-10 years, overweight girls had a 5.45-fold risk and obese girls had a 12.54-fold risk of B3 stage compared to girls with normal BMI. Compared with normal weight children, the risk of early puberty was 2.67 times higher in overweight girls, 3.63 times higher in obese girls, and 1.22 times higher in overweight boys, 1.35 times higher in obese boys (all P<0.01). Among the children at each Tanner stages, the percentage of early puberty increased with the increase of BMI, from 5.7% (80/1 397), 16.1% (48/299), 13.8% (27/195) to 25.7% (198/769), 65.1% (209/321), 65.4% (157/240) in girls aged 8-<9, 10-<11 and 11-<12 years, and 6.6% (34/513), 18.7% (51/273), 21.6% (57/264) to 13.3% (96/722), 46.4% (140/302), 47.5% (105/221) in boys aged 9-<10, 12-<13 and 13-<14 years, respectively. Conclusions: BMI is positively correlated with sexual development in both Chinese boys and girls, and the correlation is stronger in girls. Obesity is a risk factor for precocious puberty in preschool children aged 3-<6 years, and 6-<10 years of age is a high risk period for early development in obese girls.

Cholesterol Sulfate Exerts Protective Effect on Pancreatic β-Cells by Regulating β-Cell Mass and Insulin Secretion

Rational: Cholesterol sulfate (CS) is the most abundant known sterol sulfate in human plasma, and it plays a significant role in the control of metabolism and inflammatory response, which contribute to the pathogenesis of insulin resistance, β-cell dysfunction and the resultant development of diabetes. However, the role of CS in β-cells and its effect on the development of diabetes remain unknown. Here, we determined the physiological function of CS in pancreatic β-cell homeostasis.

Materials and Methods: Blood CS levels in streptozotocin (STZ)- or high-fat diet-induced diabetic mice and patients with type 1 or 2 diabetes were determined by LC-MS/MS. The impact of CS on β-cell mass and insulin secretion was investigated in vitro in isolated mouse islets and the β-cell line INS-1 and in vivo in STZ-induced diabetic mice. The molecular mechanism of CS was explored by viability assay, EdU incorporation analysis, flow cytometry, intracellular Ca²⁺ influx analysis, mitochondrial membrane potential and cellular ROS assays, and metabolism assay kits.

Results: Plasma CS levels in mice and humans were significantly elevated under diabetic conditions. CS attenuated diabetes in a low-dose STZ-induced mouse model. Mechanistically, CS promoted β-cell proliferation and protected β-cells against apoptosis under stressful conditions, which in turn preserved β-cell mass. In addition, CS supported glucose transporter-2 (GLUT2) expression and mitochondrial integrity, which then resulted in a less reactive oxygen species (ROS) generation and an increase in ATP production, thereby enabling insulin secretion machinery in the islets to function adequately.

Conclusion: This study revealed a novel dual role of CS in integrating β-cell survival and cell function, suggesting that CS might offer a physiologic approach to preserve β-cells and protect against the development of diabetes mellitus.

The suppressive functions of Rora in B lineage cell proliferation and BCR/ABL1-induced B-ALL pathogenesis

RORA plays an important role in regulating circadian rhythms, inflammation, metabolism and cellular development. Herein, we explore the roles of Rora in B cell proliferation and differentiation, as well as in Ph⁺ B-ALL. By using Rora^loxp/loxp Mx-1-Cre mice, Rora was deleted in hematopoietic cells post Pipc induction. Rora deficiency mice were associated with an obvious accumulation of B cells in the peripheral blood, bone marrow, and spleen. On the other hand, activation of Rora with Cholesterol sulfate (CS) was associated with decreased B cell numbers. RNA-seq analysis revealed that the transcription level of Lmo1 was decreased in Rora deficient B cells. Moreover, the expression of RORA was shown to be decreased in Ph⁺ B-ALL cells compared to peripheral blood derived B cells from healthy donors. The overexpression of Rora in BaF3 cells with BCR/ABL1 was also associated with impeded the cell growth and an increased apoptotic rate compared to cells transduced with BCR/ABL1 alone. The co-expression of BCR/ABL1 and Rora induced B-ALL mouse model was associated with the significant inhibition of BCR/ABL1-transformed cell growth and prolonged the survival of the diseased mice. These results suggest a novel role for Rora in B cell development and Ph⁺ leukemogenesis.

Why is COVID-19 more deadly to nursing home residents?

COVID-19 is deadly to older adults, with research showing that being older and having underlying chronic diseases are significant risk factors for COVID-19 related deaths. However, though similarities exist between both nursing home residents and older community-dwelling people, nursing home residents are substantially more vulnerable to COVID-19. A closer review of both demographic groups provides clarity concerning the difference within the context of COVID-19. Therefore, to address the research gap, drawing insights from Maslow's hierarchy of needs model, this article aims to examine similarities and differences in COVID-19 risk factors experienced by nursing home residents and community-dwelling older people.

Nuclear Factor-Y in Mouse Pancreatic β-Cells Plays a Crucial Role in Glucose Homeostasis by Regulating β-Cell Mass and Insulin Secretion

Pancreatic β-cell mass and insulin secretion are determined by the dynamic change of transcription factor expression levels in response to altered metabolic demand. Nuclear factor-Y (NF-Y) is an evolutionarily conserved transcription factor playing critical roles in multiple cellular processes. However, the physiological role of NF-Y in pancreatic β-cells is poorly understood. The current study was undertaken in a conditional knockout of Nf-ya specifically in pancreatic β-cells (Nf-ya βKO) to define the essential physiological role of NF-Y in β-cells. Nf-ya βKO mice exhibited glucose intolerance without changes in insulin sensitivity. Reduced β-cell proliferation resulting in decreased β-cell mass was observed in these mice, which was associated with disturbed actin cytoskeleton. NF-Y-deficient β-cells also exhibited impaired insulin secretion with a reduced Ca²⁺ influx in response to glucose, which was associated with an inefficient glucose uptake into β-cells due to a decreased expression of GLUT2 and a reduction in ATP production resulting from the disruption of mitochondrial integrity. This study is the first to show that NF-Y is critical for pancreatic islet homeostasis and function through regulation in β-cell proliferation, glucose uptake into β-cells, and mitochondrial energy metabolism. Modulating NF-Y expression in β-cells may therefore offer an attractive approach for therapeutic intervention.

Garlic skin induces shifts in the rumen microbiome and metabolome of fattening lambs

Garlic (Allium sativum L.) and its constituents have been shown to modify rumen fermentation and improve growth performance. Garlic skin, a by-product of garlic processing, contains similar bioactive components as garlic bulb. This study aimed to investigate the effects of garlic skin supplementation on growth performance, ruminal microbes, and metabolites in ruminants. Twelve Hu lambs were randomly assigned to receive a basal diet (CON) or a basal diet supplemented with 80 g/kg DM of garlic skin (GAS). The experiment lasted for 10 weeks, with the first 2 weeks serving as the adaptation period. The results revealed that the average daily gain and volatile fatty acid concentration were higher (P < 0.05) in lambs fed GAS than those in the CON group. Garlic skin supplementation did not significantly (P > 0.10) affect the α-diversity indices, including the Chao1 index, the abundance-based coverage estimator value, and the Shannon and Simpson indices. At the genus level, garlic skin supplementation altered the ruminal bacterial composition by increasing (P < 0.05) the relative abundances of Prevotella, Bulleidia, Howardella, and Methanosphaera and decreasing (P < 0.05) the abundance of Fretibacterium. Concentrations of 139 metabolites significantly differed (P < 0.05) between the GAS and the CON groups. Among them, substrates for rumen microbial protein synthesis were enriched in the GAS group. The pathways of pyrimidine metabolism, purine metabolism, and vitamin B6 metabolism were influenced (P < 0.05) by garlic skin supplementation. Integrated correlation analysis also provided a link between the significantly altered rumen microbiota and metabolites. Thus, supplementation of garlic skin improved the growth performance of lambs by modifying rumen fermentation through shifts in the rumen microbiome and metabolome.

Effects of propofol on proliferation and apoptosis of cardia cancer cells via MAPK/ERK signaling pathway

OBJECTIVE

To explore the influences of propofol on the proliferation and apoptosis of cardia cancer cells via mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathway.

PATIENTS AND METHODS

A total of 65 surgical resection specimens of cardia cancer were selected as research objects and divided into control group and with low (12.5 μmol/L), medium (25 μmol/L), and high (50 μmol/L) propofol concentration groups. The apoptosis of cancer cells, ERK1/2 phosphorylation level, expressions of Caspase-3, B-cell lymphoma-2 (Bcl-2), and Bcl-2 associated X protein (Bax) in each group were detected.

RESULTS

Propofol in different concentrations could all effectively inhibit the proliferation of cardia cancer cells in a dose-dependent manner. Different concentrations of propofol promoted the apoptosis of cardia cancer cells, and the apoptosis rate constantly increased with the rising concentration of propofol (p<0.05). Propofol could repress the expression of Bcl-2 and up-regulate the expression levels of Caspase-3, Bax, and phosphorylated ERK1/2.

CONCLUSIONS

Propofol can inhibit the proliferation and induce the apoptosis of cardia cancer cells, and the action mechanism may be correlated with the inhibition on the MAPK/ERK signaling pathway.

Suppression of myocardial HIF-1 by pubertal insulin resistance compromises metabolic adaptation and impairs cardiac function in patients with cyanotic congenital heart disease

Background

Cyanotic congenital heart disease (CCHD) is a complex pathophysiological condition involving systemic chronic hypoxia (CH). A proportion of CCHD patients are unoperated due to various reasons. These patients remain CH all their lives and are at increased risk of heart failure as they age. Hypoxia activates cellular metabolic adaptation to balance energy demands by accumulation of hypoxia-inducible factor 1α (HIF-1α).

Purpose

The aim of this study was to determine the effect of CH on cardiac metabolism and function in CCHD patients and how it relates with age. The mechanistic role of HIF-1α in this process was investigated and potential therapeutic targets were explored.

Methods

CCHD patients (n=20) were evaluated for cardiac metabolism and function by positron-emission tomography/computed tomography and magnetic resonance imaging. Heart tissues collected during surgical intervention were subjected to metabolomic and protein analyses. CH rodent models were generated to enable continuous observation of changes in cardiac metabolism and function. The role of HIF-1α in cardiac metabolic adaptation to CH was investigated using genetically modified animals and isotope-labeled metabolomic-pathway tracing studies.

Results

Prepubertal CCHD patients had glucose-dominant cardiac metabolism and normal cardiac function. By comparison, among patients who had entered puberty, the level of myocardial glucose uptake and glycolytic intermediates were significantly lower, but fatty acids were significantly higher, along with decreased left ventricular ejection fraction. These clinical phenotypes were replicated in CH rodent models. In patients and animals with CH, myocardial HIF-1α was upregulated prior to puberty, but was significantly downregulated during puberty. In cardiomyocyte-specific Hif-1α-knockout mice, CH failed to initiate the switch of myocardial substrates from fatty acids to glucose, leading to inhibition of ATP production and impairment of cardiac function. Increased insulin resistance (IR) suppressed myocardial HIF-1α and was responsible for cardiac metabolic maladaptation under CH during puberty. Pioglitazone significantly reduced myocardial IR, restored glucose metabolism, and improved cardiac function in pubertal animals.

Conclusions

In CCHD patients, maladaptation of cardiac metabolism occurred during puberty, impairing cardiac function. HIF-1α was identified as the key regulator of cardiac metabolic adaptation under CH but its expression was suppressed by pubertal IR. The use of pioglitazone during puberty might help improve cardiac function in these patients.

Metabolic maladaptation in CCHD patients

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): National Natural Science Foundation of China (81525002, 31971048) and Shanghai Outstanding Medical Academic Leader

Mitochondria-Associated Endoplasmic Reticulum Membranes in the Pathogenesis of Type 2 Diabetes Mellitus

The endoplasmic reticulum (ER) and mitochondria are essential intracellular organelles that actively communicate via temporally and spatially formed contacts called mitochondria-associated membranes (MAMs). These mitochondria-ER contacts are not only necessary for the physiological function of the organelles and their coordination with each other, but they also control the intracellular lipid exchange, calcium signaling, cell survival, and homeostasis in cellular metabolism. Growing evidence strongly supports the role of the mitochondria-ER connection in the insulin resistance of peripheral tissues, pancreatic β cell dysfunction, and the consequent development of type 2 diabetes mellitus (T2DM). In this review, we summarize current advances in the understanding of the mitochondria-ER connection and specifically focus on addressing a new perspective of the alterations in mitochondria-ER communication in insulin signaling and β cell maintenance.

Multiyear in-situ L-band microwave radiometry of land surface processes on the Tibetan Plateau

We report a unique multiyear L-band microwave radiometry dataset collected at the Maqu site on the eastern Tibetan Plateau and demonstrate its utilities in advancing our understandings of microwave observations of land surface processes. The presented dataset contains measurements of L-band brightness temperature by an ELBARA-III microwave radiometer in horizontal and vertical polarization, profile soil moisture and soil temperature, turbulent heat fluxes, and meteorological data from the beginning of 2016 till August 2019, while the experiment is still continuing. Auxiliary vegetation and soil texture information collected in dedicated campaigns are also reported. This dataset can be used to validate the Soil Moisture and Ocean Salinity (SMOS) and Soil Moisture Active Passive (SMAP) satellite based observations and retrievals, verify radiative transfer model assumptions and validate land surface model and reanalysis outputs, retrieve soil properties, as well as to quantify land-atmosphere exchanges of energy, water and carbon and help to reduce discrepancies and uncertainties in current Earth System Models (ESM) parameterizations. Measurement cases in winter, pre-monsoon, monsoon and post-monsoon periods are presented.

Effects of genetic variations in Acads gene on the risk of chronic obstructive pulmonary disease

Short-chain acyl-CoA dehydrogenase (SCAD), encoded by the Acads gene, functions in the mitochondrial β-oxidation of saturated short-chain fatty acids. SCAD deficiency results in mitochondrial dysfunction, which is one underlying biological mechanism of chronic obstructive pulmonary disease (COPD) pathogenesis. In this case-control study, we aimed to examine the effects of Acads gene polymorphisms on the susceptibility to COPD. A total of 16 tagging single-nucleotide polymorphisms (SNPs) in Acads gene region was identified and genotyped in 646 unrelated ethnic Chinese Han individuals including 279 patients with COPD and 367 healthy controls, their allelic and genotypic associations with COPD were determined by different genetic models. Furthermore, we estimated the linkage disequilibrium and haplotypes from these tested variants and determined the effects of haplotypes on the risk of COPD. The allelic and genotypic frequencies of SNPs rs2239686 and rs487915 in Acads gene were significantly different between COPD patients and controls, no statistically significant results were observed for other SNPs. Minor alleles A of rs2239686 and T of rs487915 were associated with a decreased pulmonary function and an increased COPD risk in a dominant manner. Functional analysis indicated that the risk allele A of rs2239686 could increase Acads expressions and the intracellular reactive oxygen species content. Haplotype analysis revealed that the haplotypes CTCCT in block 2 (rs3794216-rs3794215-rs34491494-rs558314-rs7312316) as well as GC in block 3 (rs2239686-rs487915) were protective against COPD, while haplotypes CTCGC in block 2 and AT in block 3 exhibited significant associations with the increased susceptibility to COPD. Our results suggest that Acads gene could potentially be a risk factor of COPD and thus its genetic variants might be as genetic biomarkers to predict the COPD susceptibility.

[Study of relationship between dietary patterns and precocious puberty of school-age girls in Shenzhen]

Objective: To explore the daily dietary behaviors of girls under precocious puberty and provide targeted measures for the prevention of precocious puberty. Methods: A case control study was conducted in a hospital in Shenzhen between September 2016 and December 2018. Girls with diagnosed precocious puberty were selected as case group. A 1∶1 matching was conducted. The control group was from 26 primary schools in Shenzhen. Dietary survey was conducted in parents, completing a self-administered questionnaire. Frequencies of 12 kinds of food intakes were investigated and dietary patterns were analyzed. Conditional logistic regression was used to analyze the relationship between dietary patterns and precocious puberty. Results: A total of 568 girls were included in the study. Among them, those aged 8-year-old accounted for highest proportion (43.8%). The median of age was same in both case group and control group (8 years-old). There was no significant difference in ethnic group between two groups (P>0.05). The medians of height, weight and BMI of case group were 135.0 cm, 30.2 kg and 16.6 kg/m(2), respectively, which were all higher than those of the control group (129.2 cm, 25.0 kg and 15.3 kg/m(2)), the differences were significant (P<0.05). There was significant difference in nutritional assessment result between two groups (P< 0.05). Three dietary patterns were defined, i.e. balanced pattern, high calorie and fat pattern and high protein diet pattern. The cumulative rate of variance contribution of the three dietary patterns was 0.541 2. The differences in the prevalence of three dietary patterns between two groups were significant (χ(2)=4.41, χ(2)=49.24, χ(2)=39.68, P<0.05 respectively). Data from the multivariate regression analysis showed that both balanced dietary pattern (OR=0.633, 95%CI: 0.504-0.769) and high protein diet pattern (OR=0.622, 95%CI: 0.498-0.776) were protective factors for precocious puberty, while high calorie and fat pattern was risk factors (OR=1.850, 95%CI: 1.461-2.342). Conclusions: Balanced dietary pattern was common in school-aged girls. High calorie and fat pattern was risk factor for precocious puberty. Children should be encouraged to develop a balanced dietary habit and increasing the intake of legumes and fish since they are beneficial to normal growth and development.

miR-137 alleviates focal cerebral ischemic injury in rats by regulating JAK1/STAT1 signaling pathway

The repairing effect and potential mechanism of miR-137 on cerebral ischemic injury in rats was investigated. The volume of cerebral infarction and calculated brain water content was detected by triphenyltetrazolium chloride staining. The expression of inflammatory factors was detected by enzyme-linked immunosorbent assay. The pathological damage of brain tissue was analyzed by hematoxylin and eosin and Nissl staining. The apoptosis in ischemic brain tissue was detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling. The levels of STAT1 and JAK1 proteins were analyzed by Western blot. The expression of miR-137 in primary hippocampal neurons was detected by reverse transcription polymerase chain reaction. miR-137 overexpression significantly improved brain damage in rats. miR-137 overexpression can reduce the expression of TNF-α, IL-1β, and IL-6. miR-137 overexpression can reduce the degree of brain tissue damage and inhibit the expression of JAK1 and STAT1 proteins. miR-137 overexpression can reduce oxygen-glucose deprivation (OGD)/R-induced cell damage, improve cell proliferation, and reduce apoptotic rate. JAK1 and STAT1 protein expression was inhibited in hippocampal neurons after OGD/R treatment after transfection with miR-137 mimic. After the addition of the Filgotinib inhibitor, the levels of JAK1 and STAT1 proteins were significantly reduced. The results suggested that miR-137 overexpression can effectively improve ischemic injury after focal cerebral ischemia and protect against by inhibiting JAK1/STAT1 pathway.

Mutation spectrum in GNAQ and GNA11 in Chinese uveal melanoma

Uveal melanoma is the most common intraocular cancer in the adult eye. R183 and Q209 were found to be mutational hotspots in exon 4 and exon 5 of GNAQ and GNA11 in Caucasians. However, only a few studies have reported somatic mutations in GNAQ or GNA11 in uveal melanoma in Chinese. We extracted somatic DNA from paraffin-embedded biopsies of 63 Chinese uveal melanoma samples and sequenced the entire coding regions of exons 4 and 5 in GNAQ and GNA11. The results showed that 33% of Chinese uveal melanoma samples carried Q209 mutations while none had R183 mutation in GNAQ or GNA11. In addition, seven novel missense somatic mutations in GNAQ (Y192C, F194L, P170S, D236N, L232F, V230A, and M227I) and four novel missense somatic mutations in GNA11 (R166C, I200T, S225F, and V206M) were found in our study. The high mutation frequency of Q209 and the novel missense mutations detected in this study suggest that GNAQ and GNA11 are common targets for somatic mutations in Chinese uveal melanoma.