DPP4 Gene Research Articles

Association of the rs12617656 C/T genetic variant of the DPP4 gene with in-stent restenosis in Mexican population: a cohort study.

We evaluated whether five (rs12617336, rs12617656, rs1558957, rs3788979, and rs17574) single nucleotide polymorphisms located in the DPP4 gene that have not been sufficiently explored, are candidates to be risk markers of in-stent restenosis. The genotypes were determined in 190 patients (60 patients with restenosis and 130 without restenosis) using 5'exonuclease TaqMan assays in accordance with the manufacturer's instructions (Applied Biosystems, Foster City, USA). The results showed that the CC genotype of the rs12617656 C/T SNP was associated with the risk of development restenosis after coronary stent under the co-dominant, and recessive models (odds ratios [OR] = 3.32, p = 0.0009, and OR = 4.96, p = 0.0008, respectively). In addition, our data showed that the genetic distribution of the rs12617336, rs1558957, rs3788979, and rs17574 SNPs were similar between patients with and without restenosis after coronary stenting. On the other hand, the haplotype analysis showed one haplotype (CTC) associated with restenosis susceptibility (p = 0.006). Our study demonstrates that the rs12617656 genetic variant of the DPP4 gene is associated with the risk of developing in-stent restenosis in our population.

Possible effect of OAS1 and TMPRSS6 but not DPP4 and ZNF335 polymorphisms on COVID-19 severity in the Czech population.

The acute respiratory syndrome, known as COVID-19, is characterised by high morbidity and increased mortality. Genetic factors may partially explain the differences in susceptibility to and severity of COVID-19. We have analysed common functional polymorphisms within the OAS1 (rs4767027), TMPRSS6 (rs855791), DPP4 (rs3788979), and ZNF335 (rs3848719) genes in SARS-CoV-2 positive subjects (n = 521, different disease severity) and in population controls (n = 2,559 subjects, COVID-19 status unknown). Neither DPP4 nor ZNF335 were associated with disease susceptibility or severity in the Czech population in any of the models used for calculation. T allele carriers of the OAS1 polymorphism seem to be protective against symptomatic COVID-19 (p = 0.002 calculated for trend; asymptomatic, symptomatic, hospitalised). Similarly, within the TMPRSS6, minor TT homozygotes associated with lower plasma Fe concentrations were underrepresented in the overall patient group (p = 0.044; OR = 0.77, 95% CI: 0.59-0.99), and the difference was mainly driven by the severe COVID-19 subjects. In general, risky homozygotes of these two polymorphisms were less frequent than expected in the group of hospitalised COVID-19 survivors. Common variants within OAS1 (rs4767027) and TMPRSS6 (rs855791) play some role in COVID-19 pathology in the Czech Caucasian population. Whether the depletion of minor allele carriers of these two variants is associated with increased COVID-19 mortality, needs to be analysed in an external confirmatory study.

Analysis of molecular mechanisms of the development of experimental diabetes in Wistar rats under conditions of intermittent hypoxia

There is strong evidence that hypoxic training, within the context of diabetes, constitutes a specialized form of exercise performed under conditions of intermittent hypoxia. This approach holds promise for effectively managing and enhancing diabetes outcomes, as it has the potential to influence metabolism and physiological processes within the body significantly. The key elements of hypoxic training in diabetes encompass activities geared toward activating metabolic pathways, enhancing mitochondrial function, and regulating blood glucose levels. Such interventions can potentially lead to improvements in insulin resistance, a reduction in glycemia, and an overall enhancement of cardiorespiratory function. Hypoxic training achieves these benefits by heightening insulin sensitivity and reducing blood glucose levels, which can be particularly advantageous for individuals with diabetes. The aim of the work is to determine changes in the expression of genes associated with the course of diabetes under conditions of exposure to intermittent hypoxia in pancreatic tissue samples of Wistar rats. Materials and methods. Analysis of gene expression was used by the polymerase chain reaction method with reverse transcription in real-time using the RT2 Profiler™ PCR Array Rat Diabetes kit (QIAGEN, Germany), where the pancreas of experimental animals was studied. Results. According to the results of the PCR study of animals with experimental diabetes and the influence of hypoxic training on its course, the activity of the studied genes can be divided as follows: genes with low expression compared to the control group of animals, where ∆∆Cт <30 (Ace; Cd28; Ctla4; Dusp4 ; Enpp1; Foxp3; G6pc; Gcgr; Glp1r; Gpd1; Gsk3b; Hmox1; Ide; Ikbkb; Il10; Il6; Ins1; Nfkb1; Nkx2-1; Parp1; Pdx1; Pik3cd; Pik3r1; Ppargc1a; Ptpn1; Rab4a; Retn; Slc14a2 ; Snap25; Sod2; Stx4; Stxbp1; Stxbp2; Tnf; Tnfrsf1a; Tnfrsf1b; Ucp2; Vamp2; Vegfa); genes in which no significant changes were detected in the samples in relation to the control group (Acly; Adra1a; Adrb3; Agt; Akt2; Aqp2; Ccl5; Ccr2; Ceacam1; Cebpa; Dpp4; Fbp1; Foxc2; Foxg1; Gcg; Gck; Hnf1b; Hnf4a ; Icam1; Ifng; Igfbp5; Il12b; Il4r; Inppl1; Irs1; Irs2; Mapk14; Mapk8; Neurod1; Nos3; Nrf1; Nsf; Ppara; Pparg; Pygl; Sell; Serpine1; Slc2a4; Snap23; Srebf1; Stxbp4; Tgfb1; Trib3 ; Vamp3; Vapa); there are no genes with high expression compared to the control group. Conclusions. The Nkx2-1 genes, Pik3r1, and Slc14a2 in rats subjected to experimental diabetes displayed notably reduced protein expression activity. Hypoxic training demonstrated an impact on mitigating the expression of the Nkx2-1 protein, which suggests that it might affect the mitochondrial muscle respiratory chain, modulate insulin signaling, and potentially rectify molecular deficiencies associated with diabetic nephropathy. Expression of Dpp4 genes, Gck, Ifng, Mapk8, Nsf and Sell in rats with experimental diabetes and the effect of hypoxic training on it were reduced to the level of control (intact) rats. As a result of the normalization of Dpp4 gene expression, Gck, Ifng, Mapk8, Nsf and Sell may be the influence of the effects of hypoxic training on molecular mechanisms of regulation of hormones and signals related to metabolism and the endocrine system, effects on the immune system and inflammatory processes, as well as insulin resistance.

RNA expression levels from peripheral immune cells, a minimally invasive liquid biopsy source to predict response to therapy, survival and immune-related adverse events in patients with triple negative breast cancer enrolled in the GeparNuevo trial.

1011 Background: The impact of immune checkpoint therapy on the tumor microenvironment including tumor-infiltrating immune cells is well described. However, little is known about the circulating immune repertoire and its association with treatment outcome. Hence, we set out to investigate the RNA phenotype of peripheral immune cells before and during treatment of patients enrolled in the GeparNuevo trial (Loibl S et al. Annals Oncol 2022). Methods: The GeparNuevo trial investigated the outcome after neoadjuvant nabP-EC-chemotherapy in combination with the anti-PD-L1 immune checkpoint inhibitor durvalumab versus placebo in patients with non-metastatic triple negative breast cancer. Blood was collected before therapy (baseline), after window, before epirubicin/cyclophosphamide and at end of treatment. RNA from circulating leucocytes of 117 patients was extracted and analyzed using a custom NanoString nCounter CodeSet. Expression of 290 immune-related genes was quantified. The association of RNA expression and signatures with outcome parameters like pathologic complete response (pCR), distant disease-free survival (DDFS), invasive disease-free survival (iDFS), overall survival (OS), and immune-related adverse events (irAEs) were investigated. Results: Immune cell type scores representing macrophages and neutrophils significantly increased during treatment, while B cell, T and Th1 cell scores decreased (p < 0.0001, respectively) regardless of treatment arm. Multivariate logistic respectively multivariate Cox regression analysis revealed a significant association of each baseline DPP4 and MYC gene expression with pCR, DDFS, iDFS, and OS in patients. CDK2, F5 and HLA-DR mRNA expressions were associated with the presence of irAEs. The signature score for TNFR2 non-canonical NF-kB pathway, which is known for its protective capacity, was inversely associated with irAEs in the durvalumab arm (OR = 0.454, 95% CI 0.231-0.892, p = 0.0220). Multiple immune-related signatures at baseline were associated with tumor mutational burden. Conclusions: Our study indicates the importance of the peripheral immune phenotype for treatment response and survival. This association between RNA expression levels of circulating immune cells and outcome seems to be not only relevant for patients receiving immune checkpoint therapy, but also for those under standard chemotherapy alone. Clinical trial information: NCT02685059 .

ODP575 Single-cell analysis reveals heterogeneity of mouse mammary gland fibroblasts with discrete functions, estrogen responses, differentiation, and communications with epithelium.

Abstract Mammary gland is an essential organ for milk production. It continues to develop after birth under the influence of ovarian hormones, especially estrogen. Among its cellular components, fibroblasts are recognized as an important player for mammary gland organization. Although human mammary gland fibroblasts have been classified into two subtypes based on histological localizations and different marker expressions (i. e., interlobular and intralobular fibroblasts), their detailed characteristics and functions are still limited. Moreover, despite the importance of experimental mouse models for studying mammary gland biology, heterogeneity of mouse mammary gland fibroblasts has not been fully defined. Here, we performed single-cell RNA sequencing (scRNA-seq) to determine cellular populations and their potential contributions to mammary gland organization. Based on the comprehensive gene expression profiles at a single cell level, we identified two major clusters of the mouse mammary gland fibroblasts. One of the major clusters showed the highly specific expression of Dpp4 gene, which is a known marker for human interlobular fibroblasts, and the upregulation of the inflammatory response gene signature. The other major cluster was consisted of three subclusters without Dpp4 expression, which suggested the distinct contributions to adipogenesis and/or ECM modeling in mammary gland stroma. Through the histological validation, we defined these two major subsets as "DPP4+" and "DPP4-" fibroblasts. Since our scRNA-seq was performed on two different ovarian hormone-depleted mouse models followed with hormone treatments, we evaluated the effect of the hormones, especially estrogen. The results demonstrated that the estrogen treatment altered the gene expression profiles of the DPP4+ and a subcluster of the DPP4- fibroblasts in a population-specific manner. Estrogen upregulated interferon-regulated genes and ECM genes in these fibroblast populations, respectively, but not typical estrogen-regulated genes, even in the ERα+ DPP4+ fibroblasts. To define these mammary gland fibroblasts better, we integrated our datasets with a recently established "steady-state mouse fibroblasts atlas" (1) as well as four other scRNA-seq datasets containing normal mouse mammary gland fibroblasts. Using this integrated dataset, we revealed the directional differentiation among the mammary gland fibroblasts, going from the fibroblasts and branching toward the DPP4- fibroblasts with more specialized functions. Moreover, the cell-cell interaction analysis combined with a mammary epithelium dataset from our previous publication (2) indicated possible cell-type-specific communications between mammary gland fibroblasts and epithelial cells. In conclusion, this study provided a comprehensive view of mouse mammary gland fibroblast biology at the single-cell level. Our findings would provide fundamental insights for further investigations on the roles of different fibroblast populations in mammary gland organization and pathological conditions, such as breast cancer. Reference: (1) Buechler et al., Nature. 2021 May;593(7860): 575–579. (2) Saeki et al., Commun Biol. 2021 Jun;4(1): 1–16. Presentation: No date and time listed

Exceptional diversity and selection pressure on coronavirus host receptors in bats compared to other mammals.

Pandemics originating from non-human animals highlight the need to understand how natural hosts have evolved in response to emerging human pathogens and which groups may be susceptible to infection and/or potential reservoirs to mitigate public health and conservation concerns. Multiple zoonotic coronaviruses, such as severe acute respiratory syndrome-associated coronavirus (SARS-CoV), SARS-CoV-2 and Middle Eastern respiratory syndrome-associated coronavirus (MERS-CoV), are hypothesized to have evolved in bats. We investigate angiotensin-converting enzyme 2 (ACE2), the host protein bound by SARS-CoV and SARS-CoV-2, and dipeptidyl-peptidase 4 (DPP4 or CD26), the host protein bound by MERS-CoV, in the largest bat datasets to date. Both the ACE2 and DPP4 genes are under strong selection pressure in bats, more so than in other mammals, and in residues that contact viruses. Additionally, mammalian groups vary in their similarity to humans in residues that contact SARS-CoV, SARS-CoV-2 and MERS-CoV, and increased similarity to humans in binding residues is broadly predictive of susceptibility to SARS-CoV-2. This work augments our understanding of the relationship between coronaviruses and mammals, particularly bats, provides taxonomically diverse data for studies of how host proteins are bound by coronaviruses and can inform surveillance, conservation and public health efforts.

Bioinformatics analysis reveals molecular connections between non-alcoholic fatty liver disease (NAFLD) and COVID-19.

The ongoing coronavirus disease 2019 (COVID-19) pandemic caused by SARS-CoV-2 has devastatingly impacted people’s lives. Non-alcoholic fatty liver disease (NAFLD) is fatal comorbidity of COVID-19 seen with potential risk factors to develop severe symptoms. This research focuses on determining and elucidating the molecular factors and connections that might contribute to the severity of SARS-CoV-2 infection in NAFLD patients. Here, we comprehensively inspected the genes involved in NAFLD and SARS-CoV-2 entry factors (SCEFs) found by searching through the DisGeNet database and literature review, respectively. Further, we identified the SCEFs-related proteins through protein-protein interaction (PPI) network construction, MCODE, and Cytohubba. Next, the shared genes involved in NAFLD and SARS-CoV-2 entry, and hub gene were determined, followed by the GO and KEGG pathways analysis. X2K database was used to construct the upstream regulatory network of hub genes, as well as to identify the top ten candidates of transcription factors (TFs) and protein kinases (PKs). PPI analysis identified connections between 4 top SCEFs, including ACE, ADAM17, DPP4, and TMPRSS2 and NAFLD-related genes such as ACE, DPP4, IL-10, TNF, and AKT1. GO and KEGG analysis revealed the top ten biological processes and pathways, including cytokine-mediated signaling, PI3K-Akt, AMPK, and mTOR signaling pathways. The upstream regulatory network revealed that AKT1 and MAPK14 as important PKs and HIF1A and SP1 as important TFs associated with AKT1, IL-10, and TNF. The molecular connections identified between COVID-19 and NAFLD may shed light on discovering the causes of the severity of SARS-CoV-2 infected NAFLD patients.

Prediabetes blunts DPP4 genetic control of postprandial glycaemia and insulin secretion

Aims/hypothesisImbalances in glucose metabolism are hallmarks of clinically silent prediabetes (defined as impaired fasting glucose and/or impaired glucose tolerance) representing dysmetabolism trajectories leading to type 2 diabetes. CD26/dipeptidyl peptidase 4 (DPP4) is a clinically proven molecular target of diabetes-controlling drugs but the DPP4 gene control of dysglycaemia is not proven.MethodsWe dissected the genetic control of post-OGTT and insulin release responses by the DPP4 gene in a Portuguese population-based cohort of mainly European ancestry that comprised individuals with normoglycaemia and prediabetes, and in mouse experimental models of Dpp4 deficiency and hyperenergetic diet.ResultsIn individuals with normoglycaemia, DPP4 single-nucleotide variants governed glycaemic excursions (rs4664446, p=1.63x10−7) and C-peptide release responses (rs2300757, p=6.86x10−5) upon OGTT. Association with blood glucose levels was stronger at 30 min OGTT, but a higher association with the genetic control of insulin secretion was detected in later phases of the post-OGTT response, suggesting that the DPP4 gene directly senses glucose challenges. Accordingly, in mice fed a normal chow diet but not a high-fat diet, we found that, under OGTT, expression of Dpp4 is strongly downregulated at 30 min in the mouse liver. Strikingly, no genetic association was found in prediabetic individuals, indicating that post-OGTT control by DPP4 is abrogated in prediabetes. Furthermore, Dpp4 KO mice provided concordant evidence that Dpp4 modulates post-OGTT C-peptide release in normoglycaemic but not dysmetabolic states.Conclusions/interpretationThese results showed the DPP4 gene as a strong determinant of post-OGTT levels via glucose-sensing mechanisms that are abrogated in prediabetes. We propose that impairments in DPP4 control of post-OGTT insulin responses are part of molecular mechanisms underlying early metabolic disturbances associated with type 2 diabetes.Graphical abstract

Optical genome mapping identifies rare structural variations as predisposition factors associated with severe COVID-19

SummaryImpressive global efforts have identified both rare and common gene variants associated with severe COVID-19 using sequencing technologies. However, these studies lack the sensitivity to accurately detect several classes of variants, especially large structural variants (SVs), which account for a substantial proportion of genetic diversity including clinically relevant variation. We performed optical genome mapping on 52 severely ill COVID-19 patients to identify rare/unique SVs as decisive predisposition factors associated with COVID-19. We identified 7 SVs involving genes implicated in two key host-viral interaction pathways: innate immunity and inflammatory response, and viral replication and spread in nine patients, of which SVs in STK26 and DPP4 genes are the most intriguing candidates. This study is the first to systematically assess the potential role of SVs in the pathogenesis of COVID-19 severity and highlights the need to evaluate SVs along with sequencing variants to comprehensively associate genomic information with interindividual variability in COVID-19 phenotypes.

Circulating Dipeptidyl Peptidase Activity Is a Potential Biomarker for Inflammatory Bowel Disease.

INTRODUCTION:Dipeptidyl peptidase (DPP)-4 is part of a larger family of proteases referred to as DPPs. DPP4 has been suggested as a possible biomarker for inflammatory bowel disease (IBD). Circulating DPP4 (cDPP4) enzyme activity was investigated as a potential biomarker for IBD. In addition, DPP enzyme activity and gene expression were quantified in colonic tissue of patients with IBD and non-IBD.METHODS:In study 1, DPP enzyme activity was quantified in plasma samples from 220 patients with IBD (Crohn's disease [CD] n = 130 and ulcerative colitis [UC] n = 90) and non-IBD controls (n = 26) using a colorimetric assay. In study 2, tissue and plasma samples were collected from 26 patients with IBD and 20 non-IBD controls. Plasma C-reactive protein (CRP) was quantified in all patients. Colonic DPP4, DPP8, DPP9, and fibroblast activation protein (FAP) gene expression was determined by quantitative polymerase chain reaction. cDPP and cFAP enzyme activity was also measured. Sensitivity and specificity were determined by receiver operating characteristic curve analysis.RESULTS:In study 1, total cDPP activity was found to differentiate patients with CD with active disease (n = 18) from those in remission (n = 19; sensitivity 78% and specificity 63%). In study 2, total cDPP and cFAP activity was 28% and 48% lower in patients with elevated CRP (>10 mg/L), respectively, compared with patients with normal CRP. Gene expression of DPP4, FAP, and DPP8 was also significantly higher in colonic biopsies from patients with IBD compared with non-IBD patients (P < 0.05).DISCUSSION:Our findings implicate the DPP enzyme family in intestinal inflammation and suggest future biomarker applications to differentiate the pathophysiological aspects of IBD.

The negative impact of the hominin’s DPP4 gene inherited from neanderthals to pandemic of COVID-19

The negative impact of the hominin’s DPP4 gene inherited from neanderthals to pandemic of COVID-19

Investigation of gene expression and genetic simultaneous control associated with erectile dysfunction and diabetes.

Diabetes can cause some diseases or abnormalities. One of the disorders caused by diabetes may be erectile dysfunction (ED). ED is sexual dysfunction characterized by the inability to establish or maintain an erect penis during sexual activity and is a common problem of men with chronic type 2 diabetes. These processes, disorders and diseases are highly influenced by the genetics of individuals. In this study, the relationship between genes and diabetes and ED has been explored by a system biology approach. For this purpose, the samples from ten control and diabetic-ED rats were collected. After a search in Gene Expression Omnibus (GEO), series with accession numberGSE2457 comprising of 5 normal and 5 diabetic-ED rats were selected. Raw CEL files of these samples were normalized with robust multi-array average (RMA) expression measure method by using the linear models for microarray data (LIMMA) R package. The extracted probe IDs were transformed into 10451 unique and validated official gene symbols. Then, differentially expressed genes (DEGs) were identified between control and normal penile mucosa by employing the LIMMA R package. DEGs were classified by utilizing KEGG to underlying pathways by Enrichr. The expression values of DEGs were used to construct a gene regulatory network (GRN), by the GENEI3 R package. To analyze the topology of constructed GRNs, betweenness centrality was calculated. Genes with higher betweenness centrality scores were then identified, through the CytoNCA. We then took the commonality of DEGs genes and high-top ranking genes from CytoNCA via a predicted interaction network using GeneMANIAas the most likely important genes in erectile dysfunction. Among the 374 DEGs studied, 146 DEGs showed up-regulation and 228 DEGs displayed down-regulation expression in diabetic-ED rats. According to the Volcano plot, the dpp4, LOC102553868, Ndufa412, Oxct1, Atp2b3 and Zfp91 gene down-regulated and Lpl, Retsat, B4galt1 and Pdk4 genes up-regulated in ED and diabetic rats. Furthermore, genes like dpp4 acted as hubs in the inferred GRN.

Effect of Chrysophyllum albidum fruit pulp powder on antioxidant and proinflammatory genes in non-diabetic and type 2 diabetic rats.

Diabetes mellitus (DM) is a metabolic disorder characterized by chronic hyperglycemia resulting from insulin deficiency or dysfunction. The imbalance between free radicals and antioxidants known as oxidative stress has been implicated in the pathogenesis and complications associated with DM. Chrysophyllum albidum is a seasonal fruit found to be rich in natural antioxidants. DM was induced by high-fat diet dietary supplementation for 14days followed by intraperitoneal injection of streptozotocin (35mg/kg). Thirty-five experimental rats were then divided into seven groups viz.: non-diabetic control; diabetic control; metformin; diabetic and non-diabetic fed with 5 and 10% C. albidum fruit pulp powder (CAFPP). Fasting blood glucose was done with an automatic auto-analyzer and weights were monitored at three-day intervals. The expressions of Nrf2, SOD, CAT, GST, TNF-α, DPP4, and insulin were investigated using RT-PCR. Schrödinger suites was used for docking of C. albidum phytocompounds with insulin. Diabetic rats fed with CAFPP for thirteen days have their blood glucose lowered significantly (p < 0.05) and gained weight compared to diabetic control. CAFPP significantly (p < 0.05) up-regulated Nrf2, CAT, GST, SOD, and insulin genes expression in the diabetic group relative to diabetic control with concomitant down-regulation of TNF-α and DPP4 genes expression. Molecular docking of compounds previously characterized from C. albidum revealed that they are potent ligands of insulin receptors. The study revealed that CAFPP could be effective in the management of DM-related oxidative stress by up-regulating antioxidant and down-regulating pro-inflammatory genes expression. It also positively modulates genes associated with glucose metabolism. The online version contains supplementary material available at 10.1007/s40200-021-00921-0.

The Expression of Genes Related to Lipid Metabolism and Metabolic Disorders in Children before and after Hematopoietic Stem Cell Transplantation—A Prospective Observational Study

Simple SummaryThe increasing frequency of hematopoietic stem cell transplantation (HSCT) and average postprocedural survival time has improved the knowledge about long-term adverse effects of transplantation in adulthood; i.e., an increase in the incidence of systemic diseases, like cardiovascular diseases or metabolic syndromes, as well as various types of endocrine disorders. A screening test identifying children at high risk of metabolic complications of HSCT might be useful in this group of patients. The aim of our study was to investigate the microarray-determined expression of genes with known functions related to lipid metabolism and their correlation with laboratory and clinical parameters. The next phases of research should include preemptive management of lipid abnormalities based on the results of microarray analysis. This might be the basis of personalized therapy of lipid disorders in patients with dyslipidemia or abnormalities or key metabolic hormones, both before and after HSCT.Metabolic disorders in children after hematopoietic stem cell transplantation (HSCT) are poorly characterized. However, it is known that dyslipidemia and insulin resistance are particularly common in these patients. We conducted a prospective study of 27 patients treated with HSCT to assess the possibility of predicting these abnormalities. We measured gene expressions using a microarray technique to identify differences in expression of genes associated with lipid metabolism before and after HSCT. In patients treated with HSCT, total cholesterol levels were significantly higher after the procedure compared with the values before HSCT. Microarray analysis revealed statistically significant differences in expressions of three genes, DPP4, PLAG1, and SCD, after applying the Benjamini–Hochberg procedure (pBH < 0.05). In multiple logistic regression, the increase of DPP4 gene expression before HCST (as well as its change between pre- and post-HSCT status) was associated with dyslipidemia. In children treated with HSCT, the burden of lipid disorders in short-term follow-up seems to be lower than before the procedure. The expression pattern of DPP4 is linked with dyslipidemia after the transplantation.

DPP4 Gene Polymorphism Associates With Type 2 Diabetes Mellitus in Older Adults

Genetic variations of the dipeptidyl peptidase 4 enzyme (DPP-4) have been associated with glycemic disorders, especially among older adults. The objective of this study was to investigate the association of a single nucleotide polymorphism on the DPP4 gene with the occurrence of type 2 diabetes mellitus in a sample of older community-dwelling patients. Clinical, anthropometric and physiological characteristics as well as biochemical data related to lipidemia, glycemia and hormonal factors and variables related to the lifestyle were analyzed among 338 individuals aged 60 years and older from two general geriatric outpatient clinics in the Federal District, Brazil. Genotypes related to the polymorphism rs3788979 (A/G) of the DPP4 gene of these patients were determined by conventional polymerase chain reaction followed by enzymatic restriction, whereas the serum levels of DPP-4 were assessed by colorimetric immunoassay. Among the results obtained, there was clear variation in the glycemic levels both in terms of blood glucose and glycosylated hemoglobin according to DPP-4 genotypes, with increased levels between homozygotes for the G allele. However, no association was found between genotypes and occurrence of type 2 diabetes mellitus in patients. No other clinical, biochemical or anthropometric variables were influenced by the polymorphism. In our conditions, there was no association between genotypes and DPP-4 levels. Considering that DPP-4 is involved in the metabolism of incretins and directly interferes with glycemia in organisms, our result corroborates that genetic variations of this enzyme can affect glycemic homeostasis, despite not being determinant for the occurrence of type 2 diabetes mellitus.

Insights from RNA-Seq analysis of Alzheimer's data suggest upregulation of GPCRs

Alzheimer's disease (AD) a complex neurodegenerative disorder and the most common cause of dementia in older people. Recently computational approaches have been integrated with genomics to discover novel genes involved in pathogenesis as well as to understand their mechanism. In this study we analyzed RNA-Seq data from different brain regions of AD patients and compared them with healthy individuals. Quantitative analysis of AD and control samples helped to find out differentially expressed genes (DEGs). Gene enrichment and pathway analysis were also performed to explore additional knowledge about DEGs. Study about protein-protein interaction/gene interaction, hub genes and modules helped in identifying crucial genes. It was revealed that ACKR3, CXCR4, DACH1, CDC6, GMNC, PELI2, DPP4, HSPA1L and PCGF genes were downregulated while CHRM5, CYSTLTR2, DRD5, HTR2C, PTGFR, TACR3, TRHR, MAS1, CARTPTs, DDX3Y, KDMD5, SST, GALR1, NOV, SERPINE1, HLA-B, TRIM26, and BAG-6 genes were found to be upregulated in case of AD. Network analysis of DEGs helped in understanding key pathways involved in AD disease. The analytics revealed a connection between upregulated GPCRs, presence of Aβ granules and formation of Neurofibrillary tangles. It also provides a basis of identification of novel markers and therapeutic targets for Alzheimer's disease.

Expression profiles of the SARS-CoV-2 host invasion genes in nasopharyngeal and oropharyngeal swabs of COVID-19 patients

We collect the nasopharyngeal and oropharyngeal swabs of 63 subjects with severe symptoms or contacts with COVID-19 confirmed cases to perform a pilot-study aimed to verify the “in situ” expression of SARS-CoV-2 host invasion genes (ACE2, TMPRSS2, PCSK3, EMILIN1, EMILIN2, MMRN1, MMRN2, DPP4). ACE2 (FC = +1.88, p ≤ 0.05) and DPP4 (FC = +3, p < 0.01) genes showed a significant overexpression in COVID-19 patients. ACE2 and DPP4 expression levels had a good performance (AUC = 0.75; p < 0.001) in distinguishing COVID-19 patients from negative subjects. Interestingly, we found a significant positive association of ACE2 mRNA and PCSK3, EMILIN1, MMRN1 and MMRN2 expression and of DPP4 mRNA and EMILIN2 expression only in COVID-19 patients. Noteworthy, a subgroup of severe COVID-19 (n = 7) patients, showed significant high level of ACE2 mRNA and another subgroup of less severe COVID-19 patients (n = 6) significant raised DPP4 levels.These results indicate that a group of SARS-CoV-2 host invasion genes are functionally related in COVID-19 patients and suggests that ACE2 and DPP4 expression level could act as genomic biomarkers. Moreover, at the best of our knowledge, this is the first study that shows an elevated DPP4 expression in naso- and oropharyngeal swabs of COVID-19 patient thus suggesting a functional role of DPP4 in SARS-CoV-2 infections.

COVID-19 and Genetic Variants of Protein Involved in the SARS-CoV-2 Entry into the Host Cells.

The recent global COVID-19 public health emergency is caused by SARS-CoV-2 infections and can manifest extremely variable clinical symptoms. Host human genetic variability could influence susceptibility and response to infection. It is known that ACE2 acts as a receptor for this pathogen, but the viral entry into the target cell also depends on other proteins. The aim of this study was to investigate the variability of genes coding for these proteins involved in the SARS-CoV-2 entry into the cells. We analyzed 131 COVID-19 patients by exome sequencing and examined the genetic variants of TMPRSS2, PCSK3, DPP4, and BSG genes. In total we identified seventeen variants. In PCSK3 gene, we observed a missense variant (c.893G>A) statistically more frequent compared to the EUR GnomAD reference population and a missense mutation (c.1906A>G) not found in the GnomAD database. In TMPRSS2 gene, we observed a significant difference in the frequency of c.331G>A, c.23G>T, and c.589G>A variant alleles in COVID-19 patients, compared to the corresponding allelic frequency in GnomAD. Genetic variants in these genes could influence the entry of the SARS-CoV-2. These data also support the hypothesis that host genetic variability may contribute to the variability in infection susceptibility and severity.

Changes in the transcriptional activity of the entero-insular axis genes in streptozotocin-induced diabetes and after the administration of TNF-α non-selective blockers.

The aim of the present study was to investigate the transcriptional activity of the GLP-1R, DPP-4, SGLT-1, INSR, and IGF-1R genes in GALT cells of rats with streptozotocin-induced diabetes in both untreated and treated with pentoxifylline, as a non-specific blocker of TNF-α. The expression of GLP-1R, DPP-4, SGLT-1, INSR, and IGF-1R genes in GALT cells of rats was studied by real time quantitative polymerase chain reaction. It was shown that the development of diabetes was accompanied by the decrease of GLP-1R and an increase of DPP-4 genes expression in rat ileum. The administration of pentoxifyl-line to diabetic animals led to an increase in the transcriptional activity of GLP-1R on the 4th week and decrease in transcriptional activity of DPP-4 on the 2nd and 4th weeks of the experiment. An increase in the normalized expression of SGLT-1 on the 4th week of the experimental diabetes was also noted, while the administration of pentoxifylline to diabetic animals did not lead to significant changes in this index. The transcriptional activity of the INSR and IGF-1R genes was reduced in diabetic rats and the administration of the non-specific TNF-α blocker - pentoxifylline led to a significant increase only for INSR gene in animals on the 4th week of the experimental diabetes. The expression of incretins, glucose transporters, and pro-inflammatory cytokines (e.g. TNF-α) in immune cells may be used as markers of several autoimmune pathologies progression such as type 1 diabetes due to their effect on the balance of pro- and anti-inflammatory factors.

Development of a Mouse-Adapted MERS Coronavirus.

First identified in 2012, Middle East respiratory syndrome coronavirus (MERS-CoV) is a novel virus that can cause acute respiratory distress syndrome (ARDS), multiorgan failure, and death, with a case fatality rate of ~35%. An animal model that supports MERS-CoV infection and causes severe lung disease is useful to study pathogenesis and evaluate therapies and vaccines. The murine dipeptidyl peptidase 4 (Dpp4) protein is not a functional receptor for MERS-CoV; thus, mice are resistant to MERS-CoV infection. We generated human DPP4 knock-in (hDPP4 KI) mice by replacing exons 10–12 at the mouse Dpp4 locus with exons 10–12 from the human DPP4 gene. The resultant human DPP4 KI mice are permissive to MERS-CoV (HCoV-EMC/2012 strain) infection but develop no disease. To generate a mouse model with associated morbidity and mortality from respiratory disease, we serially passaged HCoV-EMC/2012 strain in the lungs of young hDPP4 KI mice. After 30 in vivo passages, an adapted virus clone was isolated and designated MERSMA6.1.2. This virus clone produced significantly higher titers than the parental clone in the lungs of hDPP4 KI mice and caused diffuse lung injury and a fatal respiratory infection. In this chapter, we will describe in detail the procedures used to mouse adapt MERS-CoV by serial passage of the virus in lungs. We also describe the methods used to isolate virus clones and characterize virus infection.