Genetic variation of SORBS1 gene is associated with glucose homeostasis and age at onset of diabetes: A SAPPHIRe Cohort Study

Triiodothyronine (T3) promotes browning of white adipose through inhibition of the PI3K/AKT signalling pathway

Obesity arises from an imbalance between energy consumption and energy expenditure, and thyroid hormone levels serve as a determinant of energy expenditure. We conducted experiments at the animal and cellular levels and combined those findings with clinical data to elucidate the role of triiodothyronine (T3) in facilitating the browning of white adipose tissue (WAT) and its underlying mechanism. The results showed (i) the impaired metabolic function of local WAT and the compensatory elevation of systemic thermogenesis in obesity; (ii) T3 treatment of white adipocytes in vitro and local WAT in vivo induced a shift towards a morphologically "brown" phenotype, accompanied by upregulation of mRNA and protein expression of browning-related and mitochondrial function markers, which suggest that T3 intervention promotes the browning of WAT; and (iii) the aforementioned processes could be modulated through inhibition of the PI3K/AKT signalling pathway; however, whether T3 affects the PI3K/AKT signalling pathway by affecting insulin signalling remains to be studied and clarified. The results of our study indicate that T3 treatment promotes browning of WAT through inhibition of the PI3K/AKT signalling pathway; these findings offer novel perspectives regarding the potential of localised therapies for addressing WAT volume in individuals with obesity.

Methylome-wide and meQTL analysis helps to distinguish treatment response from non-response and pathogenesis markers in schizophrenia

Schizophrenia is a complex condition with entwined genetic and epigenetic risk factors, posing a challenge to disentangle the intermixed pathological and therapeutic epigenetic signatures. To resolve this, we performed 850K methylome-wide and 700K genome-wide studies on the same set of schizophrenia patients by stratifying them into responders, non-responders, and drug-naïve patients. The key genes that signified the response were followed up using real-time gene expression studies to understand the effect of antipsychotics at the gene transcription level. The study primarily implicates hypermethylation in therapeutic response and hypomethylation in the drug-non-responsive state. Several differentially methylated sites and regions colocalized with the schizophrenia genome-wide association study (GWAS) risk genes and variants, supporting the convoluted gene-environment association. Gene ontology and protein-protein interaction (PPI) network analyses revealed distinct patterns that differentiated the treatment response from drug resistance. The study highlights the strong involvement of several processes related to nervous system development, cell adhesion, and signaling in the antipsychotic response. The ability of antipsychotic medications to alter the pathology by modulating gene expression or methylation patterns is evident from the general increase in the gene expression of response markers and histone modifiers and the decrease in class II human leukocyte antigen (HLA) genes following treatment with varying concentrations of medications like clozapine, olanzapine, risperidone, and haloperidol. The study indicates a directional overlap of methylation markers between pathogenesis and therapeutic response, thereby suggesting a careful distinction of methylation markers of pathogenesis from treatment response. In addition, there is a need to understand the trade-off between genetic and epigenetic observations. It is suggested that methylomic changes brought about by drugs need careful evaluation for their positive effects on pathogenesis, course of disease progression, symptom severity, side effects, and refractoriness.

Tirzepatide prevents neurodegeneration through multiple molecular pathways

BACKGROUND

Several evidence demonstrated that glucagon-like peptide 1 receptor agonists (GLP1-RAs) reduce the risk of dementia in type 2 diabetes patients by improving memory, learning, and overcoming cognitive impairment. In this study, we elucidated the molecular processes underlying the protective effect of Tirzepatide (TIR), a dual glucose-dependent insulinotropic polypeptide receptor agonist (GIP-RA)/ GLP-1RA, against learning and memory disorders.

METHODS

We investigated the effects of TIR on markers of neuronal growth (CREB and BDNF), apoptosis (BAX/Bcl2 ratio) differentiation (pAkt, MAP2, GAP43, and AGBL4), and insulin resistance (GLUT1, GLUT4, GLUT3 and SORBS1) in a neuroblastoma cell line (SHSY5Y) exposed to normal and high glucose concentration. The potential role on DNA methylation of genes involved in neuroprotection and epigenetic modulators of neuronal growth (miRNA 34a), apoptosis (miRNA 212), and differentiation (miRNA 29c) was also investigated. The cell proliferation was detected by measuring Ki-67 through flow cytometry. The data were analysed by SPSS IBM Version 23 or GraphPad Prism 7.0 software and expressed as the means ± SEM. Differences between the mean values were considered significant at a p-value of < 0.05. GraphPad Prism software was used for drawing figures.

RESULTS

For the first time, it was highlighted: (a) the role of TIR in the activation of the pAkt/CREB/BDNF pathway and the downstream signaling cascade; (b) TIR efficacy in neuroprotection; (c) TIR counteracting of hyperglycemia and insulin resistance-related effects at the neuronal level.

CONCLUSIONS

We demonstrated that TIR can ameliorate high glucose-induced neurodegeneration and overcome neuronal insulin resistance. Thus, this study provides new insight into the potential role of TIR in improving diabetes-related neuropathy.

Increased serum extrachromosomal circular DNA SORBS1circle level is associated with insulin resistance in patients with newly diagnosed type 2 diabetes mellitus

BACKGROUND

Extrachromosomal circular DNAs (eccDNAs) exist in human blood and somatic cells, and are essential for oncogene plasticity and drug resistance. However, the presence and impact of eccDNAs in type 2 diabetes mellitus (T2DM) remains inadequately understood.

METHODS

We purified and sequenced the serum eccDNAs obtained from newly diagnosed T2DM patients and normal control (NC) subjects using Circle-sequencing. We validated the level of a novel circulating eccDNA named sorbin and SH3-domain- containing-1circle97206791-97208025 (SORBS1circle) in 106 newly diagnosed T2DM patients. The relationship between eccDNA SORBS1circle and clinical data was analyzed. Furthermore, we explored the source and expression level of eccDNA SORBS1circle in the high glucose and palmitate (HG/PA)-induced hepatocyte (HepG2 cell) insulin resistance model.

RESULTS

A total of 22,543 and 19,195 eccDNAs were found in serum samples obtained from newly diagnosed T2DM patients and NC subjects, respectively. The T2DM patients had a greater distribution of eccDNA on chromosomes 1, 14, 16, 17, 18, 19, 20 and X. Additionally, 598 serum eccDNAs were found to be upregulated, while 856 eccDNAs were downregulated in T2DM patients compared with NC subjects. KEGG analysis demonstrated that the genes carried by eccDNAs were mainly associated with insulin resistance. Moreover, it was validated that the eccDNA SORBS1circle was significantly increased in serum of newly diagnosed T2DM patients (106 T2DM patients vs. 40 NC subjects). The serum eccDNA SORBS1circle content was positively correlated with the levels of glycosylated hemoglobin A1C (HbA1C) and homeostasis model assessment of insulin resistance (HOMA-IR) in T2DM patients. Intracellular eccDNA SORBS1circle expression was significantly enhanced in the high glucose and palmitate (HG/PA)-induced hepatocyte (HepG2 cell) insulin resistance model. Moreover, the upregulation of eccDNA SORBS1circle in the HG/PA-treated HepG2 cells was dependent on generation of apoptotic DNA fragmentation.

CONCLUSIONS

These results provide a preliminary understanding of the circulating eccDNA patterns at the early stage of T2DM and suggest that eccDNA SORBS1circle may be involved in the development of insulin resistance.

Stereotactic body radiation therapy suppresses myeloid-derived suppressor cells by regulating miR-21/Sorbin and SH3 Domain-containing Protein 1 axis

BACKGROUND

Stereotactic body radiation therapy (SBRT) is a targeted form of radiotherapy used to treat early-stage cancers. Despite its effectiveness, the impact of SBRT on myeloid-derived suppressor cells (MDSCs) is not well understood. In this study, we examined how SBRT affects the differentiation and survival of MDSCs, as well as delved into the molecular mechanisms involved.

METHODS AND RESULTS

SBRT was utilized on bone marrow (BM)-derived MDSCs to investigate its impact on the differentiation and survival of MDSCs using flow cytometry. An animal model of lung cancer was created to assess the anti-cancer properties of SBRT and the role of miR-21 expression in MDSCs. The interplay of miR-21 and Sorbin and SH3 domain-containing protein 1 (SORBS1) in MDSC differentiation was explored through dual luciferase activity assay, RT-qPCR, and Western blot analysis. The findings suggest that SBRT led to an increase in miR-21 levels, inhibited MDSC differentiation, and triggered cell apoptosis in BM cells. Inhibition of miR-21 reversed the effects of SBRT on MDSC differentiation and apoptosis. Additionally, it was revealed that SORBS1 was a downstream target of miR-21 in BM cells, and the miR-21/SORBS1 axis played a role in regulating MDSC differentiation and apoptosis induced by SBRT. Modulating miR-21 levels in vivo impinged on the response to SBRT treatment and the quantity of MDSCs in a mouse model of lung cancer.

CONCLUSION

Our data indicate that the upregulation of miR-21 induced by SBRT may contribute to the inhibition of MDSC expansion in a lung cancer model.

DOCK3 regulates normal skeletal muscle regeneration and glucose metabolism

DOCK (dedicator of cytokinesis) is an 11-member family of typical guanine nucleotide exchange factors (GEFs) expressed in the brain, spinal cord, and skeletal muscle. Several DOCK proteins have been implicated in maintaining several myogenic processes such as fusion. We previously identified DOCK3 as being strongly upregulated in Duchenne muscular dystrophy (DMD), specifically in the skeletal muscles of DMD patients and dystrophic mice. Dock3 ubiquitous KO mice on the dystrophin-deficient background exacerbated skeletal muscle and cardiac phenotypes. We generated Dock3 conditional skeletal muscle knockout mice (Dock3 mKO) to characterize the role of DOCK3 protein exclusively in the adult muscle lineage. Dock3 mKO mice presented with significant hyperglycemia and increased fat mass, indicating a metabolic role in the maintenance of skeletal muscle health. Dock3 mKO mice had impaired muscle architecture, reduced locomotor activity, impaired myofiber regeneration, and metabolic dysfunction. We identified a novel DOCK3 interaction with SORBS1 through the C-terminal domain of DOCK3 that may account for its metabolic dysregulation. Together, these findings demonstrate an essential role for DOCK3 in skeletal muscle independent of DOCK3 function in neuronal lineages.

Propranolol treatment during repetitive mild traumatic brain injuries induces transcriptomic changes in the bone marrow of mice

Introduction

There are 1.5 million new mild traumatic brain injuries (mTBI) annually in the US, with many of the injured experiencing long-term consequences lasting months after the injury. Although the post injury mechanisms are not well understood, current knowledge indicates peripheral immune system activation as a causal link between mTBI and long-term side effects. Through a variety of mechanisms, peripheral innate immune cells are recruited to the CNS after TBI to repair and heal the injured tissue; however, the recruitment and activation of these cells leads to further inflammation. Emerging evidence suggests sympathetic nervous system (SNS) activity plays a substantial role in the recruitment of immune cells post injury.

Methods

We sought to identify the peripheral innate immune response after repeated TBIs in addition to repurposing the nonselective beta blocker propranolol as a novel mTBI therapy to limit SNS activity and mTBI pathophysiology in the mouse. Mice underwent repetitive mTBI or sham injury followed by i.p. saline or propranolol. Isolated mRNA derived from femur bone marrow of mice was assayed for changes in gene expression at one day, one week, and four weeks using Nanostring nCounter® stem cell characterization panel.

Results

Differential gene expression analysis for bone marrow uncovered significant changes in many genes following drug alone, mTBI alone and drug combined with mTBI.

Discussion

Our data displays changes in mRNA at various timepoints, most pronounced in the mTBI propranolol group, suggesting a single dose propranolol injection as a viable future mTBI therapy in the acute setting.

Preliminary observational study of metabonomics in patients with early and late-onset type 2 diabetes mellitus based on UPLC-Q-TOF/MS

Non-targeted metabonomic techniques were used to explore changes in metabolic profiles of patients with early onset and late onset T2DM. Newly diagnosed early onset T2DM (EarT2DM) and late onset T2DM (LatT2DM) patients were recruited, and the matched age, sex, and low-risk population of diabetes mellitus were selected as the control group. 117 adults were recruited in the study, including 21 in EarT2DM group with 25 in corresponding control group (heaCG1), and 48 in LatT2DM group with 23 in corresponding control group (heaCG2). There were 15 relatively distinctive metabolic variants in EarT2DM group and 10 distinctive metabolic variants in LatT2DM group. The same changing pathways mainly involved protein, aminoacyl-tRNA biosynthesis, fatty acid biosynthesis, taurine metabolism, arginine biosynthesis, lysosome and mTOR signaling pathway. The independent disturbed pathways in EarT2DM included branched chain amino acids, alanine, aspartate and glutamate metabolism. The independent disturbed pathways in LatT2DM involved linoleic acid metabolism, biosynthesis of unsaturated fatty acids, arginine, proline metabolism and FoxO signaling pathway. T2DM patients at different diagnosed ages may have different metabolite profiles. These metabolic differences need to be further verified.

DOCK3 regulates normal skeletal muscle regeneration and glucose metabolism

DOCK (dedicator of cytokinesis) is an 11-member family of typical guanine nucleotide exchange factors (GEFs) expressed in the brain, spinal cord, and skeletal muscle. Several DOCK proteins have been implicated in maintaining several myogenic processes such as fusion. We previously identified DOCK3 as being strongly upregulated in Duchenne muscular dystrophy (DMD), specifically in the skeletal muscles of DMD patients and dystrophic mice. Dock3 ubiquitous KO mice on the dystrophin-deficient background exacerbated skeletal muscle and cardiac phenotypes. We generated Dock3 conditional skeletal muscle knockout mice (Dock3 mKO) to characterize the role of DOCK3 protein exclusively in the adult muscle lineage. Dock3 mKO mice presented with significant hyperglycemia and increased fat mass, indicating a metabolic role in the maintenance of skeletal muscle health. Dock3 mKO mice had impaired muscle architecture, reduced locomotor activity, impaired myofiber regeneration, and metabolic dysfunction. We identified a novel DOCK3 interaction with SORBS1 through the C-terminal domain of DOCK3 that may account for its metabolic dysregulation. Together, these findings demonstrate an essential role for DOCK3 in skeletal muscle independent of DOCK3 function in neuronal lineages.

CBL/CAP Is Essential for Mitochondria Respiration Complex I Assembly and Bioenergetics Efficiency in Muscle Cells

CBL is rapidly phosphorylated upon insulin receptor activation. Mice whole body CBL depletion improved insulin sensitivity and glucose clearance; however, the precise mechanisms remain unknown. We depleted either CBL or its associated protein SORBS1/CAP independently in myocytes and assessed mitochondrial function and metabolism compared to control cells. CBL- and CAP-depleted cells showed increased mitochondrial mass with greater proton leak. Mitochondrial respiratory complex I activity and assembly into respirasomes were reduced. Proteome profiling revealed alterations in proteins involved in glycolysis and fatty acid degradation. Our findings demonstrate CBL/CAP pathway couples insulin signaling to efficient mitochondrial respiratory function and metabolism in muscle.

Suicide-Related Single Nucleotide Polymorphisms, rs4918918 and rs10903034: Association with Dementia in Older Adults

Dementia has enormous implications for patients and the health care system. Genetic markers are promising for detecting the risk of cognitive impairment. We hypothesized that genetic variants associated with suicide risk might significantly increase the risk of cognitive decline because suicide in older adults is often a consequence of cognitive impairment. We investigated several single-nucleotide polymorphisms that were initially associated with suicide risk in dementia older adults and identified the APOE gene alleles. The study was performed with subjects over the age of 65: 112 patients with dementia and 146 healthy volunteers. The MMSE score was used to assess cognitive functions. Study participants were genotyped using real-time PCR (APOE: rs429358, rs7412; genes associated with suicide: rs9475195, rs7982251, rs2834789, rs358592, rs4918918, rs3781878, rs10903034, rs165774, rs16841143, rs11833579 rs10898553, rs7296262, rs3806263, and rs2462021). Genotype analysis revealed the significance of APOEε4, APOEε2, and rs4918918 (SORBS1) when comparing dementia and healthy control groups. The association of APOEε4, APOEε2, and rs10903034 (IFNLR1) with the overall MMSE score was indicated. The study found an association with dementia of rs4918918 (SORBS1) and rs10903034 (IFNLR1) previously associated with suicide and confirmed the association of APOEε4 and APOEε2 with dementia.

The Joint Public Health Impact of Family History of Diabetes and Cardiovascular Disease among Adults in the United States: A Population-Based Study

INTRODUCTION

Family history is an established risk factor for both cardiovascular disease (CVD) and diabetes; however, no study has presented population-based prevalence estimates of family histories of CVD and diabetes and examined their joint impact on prevalence of diabetes, CVD, cardiometabolic risk factors, and mortality risk.

METHODS

We analyzed data from a representative sample of the US adult population including 29,440 participants from the National Health and Nutrition Examination Survey (2007-2018) and assessed self-reported first-degree family history of diabetes and CVD (premature heart disease before age of 50 years) as well as meeting criteria and/or having risk factors for CVD and diabetes.

RESULTS

Participants with joint family history exhibit 6.5 greater odds for having both diseases and are diagnosed with diabetes 6.6 years earlier than participants without family history. Healthy participants without prevalent CVD or diabetes but with joint family history exhibit a greater prevalence of diabetes risk factors compared to no family history counterparts. Joint family history is associated with an increase in all-cause mortality, but with no interactive effect.

CONCLUSION

Over 44% of the US adult population has a family history of CVD and/or diabetes that is comparable in risk to common cardiometabolic risk factors. This wide presence of high-risk family history and its simplicity of ascertainment suggests that clinical and public health efforts should collect and act on joint family history of CVD and diabetes to improve population efforts in the prevention and early detection of these common chronic diseases.

Development and Validation of a Prognostic Classifier Based on Lipid Metabolism-Related Genes for Breast Cancer

Background

The changes of lipid metabolism have been implicated in the development of many tumors, but its role in breast invasive carcinoma (BRCA) remains to be fully established. Here, we attempted to ascertain the prognostic value of lipid metabolism-related genes in BRCA.

Methods

We obtained RNA expression data and clinical information for BRCA and normal samples from public databases and downloaded a lipid metabolism-related gene set. Ingenuity Pathway Analysis (IPA) was applied to identify the potential pathways and functions of Differentially Expressed Genes (DEGs) related to lipid metabolism. Subsequently, univariate and multivariate Cox regression analyses were utilized to construct the prognostic gene signature. Functional enrichment analysis of prognostic genes was achieved by the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). Kaplan-Meier analysis, Receiver Operating Characteristic (ROC) curves, clinical follow-up results were employed to assess the prognostic potency. Potential compounds targeting prognostic genes were screened by Connectivity Map (CMap) database and a prognostic gene-drug interaction network was constructed using Comparative Toxicogenomics Database (CTD). Furthermore, we separately validated the selected marker genes in BRCA samples and human breast cancer cell lines (MCF-7, MDA-MB-231).

Results

IPA and functional enrichment analysis demonstrated that the 162 lipid metabolism-related DEGs we obtained were involved in many lipid metabolism and BRCA pathological signatures. The prognostic classifier we constructed comprising SDC1 and SORBS1 can serve as an independent prognostic marker for BRCA. CMap filtered 37 potential compounds against prognostic genes, of which 16 compounds could target both two prognostic genes were identified by CTD. The functions of the two prognostic genes in breast cancer cells were verified by cell function experiments.

Conclusion

Within this study, we identified a novel prognostic classifier based on two lipid metabolism-related genes: SDC1 and SORBS1. This result highlighted a new perspective on the metabolic exploration of BRCA.

Polymorphisms of SORBS1 Gene and Their Correlation with Milk Fat Traits of Cattleyak

Simple Summary

Increasing milk fat rate has a good effect on the milk quality of cattleyak. SNPs can help us find potential molecular markers for the milk fat traits of cattleyak, and they can be screened according to molecular markers when they are young. It provides a reference for cultivating high milk fat cattle population in the future. The results of this study suggest that the SORBS1 gene polymorphism is closely related to the milk fat traits of cattleyak, which could be used as a candidate genetic marker for milk fat trait selection in cattleyak. This study provides a new molecular marker and theoretical basis for screening the milk fat traits of cattleyak. It has a certain reference value for the research and improvement of milk quality.

Abstract

This study aimed to find the SNPs in the SORBS1 gene of cattleyak, analyze the relationship between its polymorphisms and the milk fat traits, and find potential molecular markers for the milk fat traits of cattleyak. The polymorphism of the SORBS1 gene in 350 cattleyak from Hongyuan County (Sichuan, China) were detected by PCR and DNA sequencing, and the correlation between these SNPs and the milk production traits of cattleyak was analyzed. The results showed that there were nine SNPs in the CDS and their adjacent non-coding regions of the SORBS1 gene, and all SNPs have three genotypes. The correlation analysis found that the genotypes with superior milk fat traits in the other eight alleles were homozygous genotypes with a high genotype frequency except the g.96284 G > A (c.3090 G > A) (p < 0.05). However, at locus g.96284 G > A, the milk fat percentage, monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFAs) of the GA genotype were significantly higher than that of GG and AA genotypes (p < 0.05). Among these SNPs, three SNPs (g.6256 C > T (c.298 C > T), g.24791 A > G (c.706 A > G) and g.29121 A > G (c.979 A > G)) caused the amino acids change. The genotypes of the three SNPs consist of three haplotypes and four diplotypes. The amino acid mutation degree of diplotype H1–H1 (CCAAAA) was the highest, and its milk fat percentage, MUFAs, PUFAs and SFAs were also the highest (p < 0.05). Taken together, we found nine SNPs in the SORBS1 gene that are closely related to the milk fat traits of cattleyak. Moreover, the mutation of amino acids caused by SNPs had positive effects on the milk fat traits of cattleyak. H1-H1 is the dominant diplotype which significantly related to the milk fat traits of cattleyak. This study provides a new molecular marker and theoretical basis for screening the milk fat traits of cattleyak.

Insulin signaling in health and disease

The molecular mechanisms of cellular insulin action have been the focus of much investigation since the discovery of the hormone 100 years ago. Insulin action is impaired in metabolic syndrome, a condition known as insulin resistance. The actions of the hormone are initiated by binding to its receptor on the surface of target cells. The receptor is an α2β2 heterodimer that binds to insulin with high affinity, resulting in the activation of its tyrosine kinase activity. Once activated, the receptor can phosphorylate a number of intracellular substrates that initiate discrete signaling pathways. The tyrosine phosphorylation of some substrates activates phosphatidylinositol-3-kinase (PI3K), which produces polyphosphoinositides that interact with protein kinases, leading to activation of the kinase Akt. Phosphorylation of Shc leads to activation of the Ras/MAP kinase pathway. Phosphorylation of SH2B2 and of Cbl initiates activation of G proteins such as TC10. Activation of Akt and other protein kinases produces phosphorylation of a variety of substrates, including transcription factors, GTPase-activating proteins, and other kinases that control key metabolic events. Among the cellular processes controlled by insulin are vesicle trafficking, activities of metabolic enzymes, transcriptional factors, and degradation of insulin itself. Together these complex processes are coordinated to ensure glucose homeostasis.

Evaluation of the Therapeutic Effect of Lycoramine on Alzheimer's Disease in Mouse Model

BACKGROUND

Alzheimer's disease is one of the leading health problems characterized by the accumulation of Aβ and hyperphosphorylated tau that account for the senile plaque formations causing extensive cognitive decline. Many of the clinical diagnoses of Alzheimer's disease are made in the late stages, when the pathological changes have already progressed.

OBJECTIVE

The objective of this study is to evaluate the promising therapeutic effects of a natural compound, lycoramine, which has been shown to have therapeutic potential in several studies and to understand its mechanism of action on the molecular level via differential protein expression analyses.

METHODS

Lycoramine and galantamine, an FDA approved drug used in the treatment of mild to moderate AD, were administered to 12 month-old 5xFAD mice. Effects of the compounds were investigated by Morris water maze, immunohistochemistry and label- free differential protein expression analyses.

RESULTS

Here we demonstrated the reversal of cognitive decline via behavioral testing and the clearance of Aβ plaques. Proteomics analysis provided in-depth information on the statistically significant protein perturbations in the cortex, hippocampus and cerebellum sections to hypothesize the possible clearance mechanisms of the plaque formation and the molecular mechanism of the reversal of cognitive decline in a transgenic mouse model. Bioinformatics analyses showed altered molecular pathways that can be linked with the reversal of cognitive decline observed after lycoramine administration but not with galantamine.

CONCLUSION

Lycoramine shows therapeutic potential to halt and reverse cognitive decline at the late stages of disease progression, and holds great promise for the treatment of Alzheimer's disease.

Impact of Genetic Factors on the Age of Onset for Type 2 Diabetes Mellitus in Addition to the Conventional Risk Factors

It is generally accepted that the early detection of type 2 diabetes mellitus (T2DM) is important to prevent the development of complications and comorbidities, as well as premature death. The onset of type 2 diabetes mellitus results from a complex interplay between genetic, environmental, and lifestyle risk factors. Our study aims to evaluate the joint effect of T2DM associated single nucleotide polymorphisms (SNPs) on the age of onset for T2DM in combination with conventional risk factors (such as sex, body mass index (BMI), and TG/HDL-C ratio) in the Hungarian population. This study includes 881 T2DM patients (Case population) and 1415 samples from the Hungarian general population (HG). Twenty-three SNPs were tested on how they are associated with the age of onset for T2DM in the Case population and 12 of them with a certified effect on the age of T2DM onset were chosen for an optimized genetic risk score (GRS) analysis. Testing the validity of the GRS model developed was carried out on the HG population. The GRS showed a significant association with the age of onset for T2DM (β = -0.454, p = 0.001) in the Case population, as well as among T2DM patients in the HG one (β = -0.999, p = 0.003) in the replication study. The higher the GRS, the earlier was the T2DM onset. Individuals with more than eight risk alleles will presumably be diabetic six and a half years earlier than those with less than four risk alleles. Our results suggest that there is a considerable genetic predisposition for the early onset of T2DM; therefore, in addition to conventional risk factors, GRS can be used as a tool for estimating the risk of the earlier onset of T2DM and stratifying populations at risk in order to define preventive interventions.

Early-onset type 2 diabetes is associated with genetic variants of β-cell function in the Chinese Han population

AIMS

To investigate the genetic factors contributing to early-onset type 2 diabetes (EOD) in the Chinese Hans populations.

MATERIALS AND METHODS

For 2734 newly diagnosed type 2 diabetes patients and 4041 normal glycemic controls, 25 single nucleotide polymorphisms from 24 genomic loci linked to diabetes were successfully genotyped. Three genetic risk scores (GRSs) were constructed, including the weighted type 2 diabetes-related GRS (wT-GRS), the weighted β-cell function-related GRS (wB-GRS), and the weighted GRS constructed by risk alleles not related to β-cell function (wNB-GRS). For patients with diabetes, EOD, middle-age-onset type 2 diabetes (MOD), and late-onset type 2 diabetes (LOD) were defined by onset ages ≤40, 40 to 60, and ≥60 years, respectively.

RESULTS

From single marker analysis, different gene profiles were identified between EOD and LOD patients. EOD patients had greater wT-GRS and wB-GRS values than LOD patients. After adjustment for sex, elevated wT-GRS and wB-GRS values were significantly associated with an increased risk for EOD by 1.11- and 1.21-fold per allele (P = 1.69 × 10^-7 ; 6.07 × 10^-8 ). The wT-GRS and wNB-GRS were nominally related to an increased risk of LOD by 1.03-fold per allele (P = 1.03 × 10^-2 , 1.78 × 10^-2 ). In patients with diabetes, higher wT-GRS and wB-GRS were associated with younger onset age [wT-GRS: β (SE) = -0.0033(0.0016), P = 3.74 × 10^-2 ; wB-GRS: -0.0076(0.0028), 7.45 × 10^-3 ] and decreased insulinogenic index [wT-GRS: -0.0384(0.0098), 9.39 × 10^-5 ; wB-GRS: -0.0722(0.0176), 4.21 × 10^-5 ].

CONCLUSION

Our findings indicate a strong genetic predisposition for EOD, which can be mainly attributed to genetic variants linked to β-cell function, suggesting the β-cell dysfunction plays a key role in the pathogenesis of EOD in Chinese Han individuals.

Quantitative Proteomic and Network Analysis of Differentially Expressed Proteins in PBMC of Friedreich's Ataxia (FRDA) Patients

Friedreich’s ataxia (FRDA) is an autosomal recessive neurodegenerative disorder caused by an expanded (GAA) trinucleotide repeat in the FXN gene. The extended repeats expansion results in reduced transcription and, thereby, decreased expression of the mitochondrial protein, frataxin. Given the ongoing drug trials, identification of reliable and easily accessible biomarkers for monitoring disease progression and therapeutic intervention is a foremost requirement. In this study, comparative proteomic profiling of PBMC proteins from FRDA patients and age- and gender-matched healthy controls was done using 2D-Differential in-Gel Electrophoresis (2D-DIGE). Protein–protein interaction (PPI) was analyzed using BioGRID and STRING pathway analysis tools. Using biological variance analysis (BVA) and LC/MS, we found eight differentially expressed proteins with fold change ≥1.5; p ≤ 0.05. Based on their cellular function, the identified proteins showed a strong pathological role in neuroinflammation, cardiomyopathy, compromised glucose metabolism, and iron transport, which are the major clinical manifestations of FRDA. Protein–protein network analysis of differentially expressed proteins with frataxin further supports their involvement in the pathophysiology of FRDA. Considering their crucial role in the cardiac and neurological complications, respectively, the two down-regulated proteins, actin α cardiac muscle 1 (ACTC1) and pyruvate dehydrogenase E1 component subunit β (PDHE1), are suggested as potential prognostic markers for FRDA.

Transcriptomic Responses of Skeletal Muscle to Acute Exercise in Diabetic Goto-Kakizaki Rats

Physical activity exerts positive effects on glycemic control in type 2 diabetes (T2D), which is mediated in part by extensive metabolic and molecular remodeling of skeletal muscle in response to exercise, while many regulators of skeletal muscle remain unclear. In the present study, we investigated the effects of acute exercise on skeletal muscle transcriptomic responses in the Goto-Kakizaki (GK) rats which can spontaneously develop T2D. The transcriptomes of skeletal muscle from both 8-week-old GK and Wistar rats that underwent a single exercise session (60 min running using an animal treadmill at 15 m/min) or remained sedentary were analyzed by next-generation RNA sequencing. We identified 819 differentially expressed genes in the sedentary GK rats compared with those of the sedentary Wistar rats. After a single bout of running, we found 291 and 598 genes that were differentially expressed in the exercise GK and exercise Wistar rats when compared with the corresponding sedentary rats. By integrating our data and previous studies including RNA or protein expression patterns and transgenic experiments, the downregulated expression of Fasn and upregulated expression of Tbc1d1, Hk2, Lpin1, Ppargc1a, Sorbs1, and Hmox1 might enhance glucose uptake or improve insulin sensitivity to ameliorate hyperglycemia in the exercise GK rats. Our results provide mechanistic insight into the beneficial effects of exercise on hyperglycemia and insulin action in skeletal muscle of diabetic GK rats.