Dipeptidyl Peptidase-4 Regulates Hematopoietic Stem Cell Activation in Response to Chronic Stress

Dipeptidyl peptidase-4 disturbs adipocyte differentiation via the negative regulation of the glucagon-like peptide-1/adiponectin-cathepsin K axis in mice under chronic stress conditions

Exposure to chronic psychosocial stress is a risk factor for metabolic disorders. Because dipeptidyl peptidase-4 (DPP4) and cysteinyl cathepsin K (CTSK) play important roles in human pathobiology, we investigated the role(s) of DPP4 in stress-related adipocyte differentiation, with a focus on the glucagon-like peptide-1 (GLP-1)/adiponectin-CTSK axis in vivo and in vitro. Plasma and inguinal adipose tissue from non-stress wild-type (DPP4+/+), DPP4-knockout (DPP4-/-) and CTSK-knockout (CTSK-/-) mice, and stressed DPP4+/+, DPP4-/-, CTSK-/-, and DPP4+/+ mice underwent stress exposure plus GLP-1 receptor agonist exenatide loading for 2 weeks and then were analyzed for stress-related biological and/or morphological alterations. On day 14 under chronic stress, stress decreased the weights of adipose tissue and resulted in harmful changes in the plasma levels of DPP4, GLP-1, CTSK, adiponectin, and tumor necrosis factor-α proteins and the adipose tissue levels of CTSK, preadipocyte factor-1, fatty acid binding protein-4, CCAAT/enhancer binding protein-α, GLP-1 receptor, peroxisome proliferator-activated receptor-γ, perilipin2, secreted frizzled-related protein-4, Wnt5α, Wnt11 and β-catenin proteins and/or mRNAs as well as macrophage infiltration in adipose tissue; these changes were rectified by DPP4 deletion. GLP-1 receptor activation and CTSK deletion mimic the adipose benefits of DPP4 deficiency. In vitro, CTSK silencing and overexpression respectively prevented and facilitated stress serum and oxidative stress-induced adipocyte differentiation accompanied with changes in the levels of pref-1, C/EBP-α, and PPAR-γ in 3T3-L1 cells. Thus, these findings indicated that increased DPP4 plays an essential role in stress-related adipocyte differentiation, possibly through a negative regulation of GLP-1/adiponectin-CTSK axis activation in mice under chronic stress conditions.

Cathepsin K deficiency prevented stress-related thrombosis in a mouse FeCl3 model

BACKGROUND

Exposure to chronic psychological stress (CPS) is a risk factor for thrombotic cardiocerebrovascular diseases (CCVDs). The expression and activity of the cysteine cathepsin K (CTSK) are upregulated in stressed cardiovascular tissues, and we investigated whether CTSK is involved in chronic stress-related thrombosis, focusing on stress serum-induced endothelial apoptosis.

METHODS AND RESULTS

Eight-week-old wild-type male mice (CTSK+/+) randomly divided to non-stress and 3-week restraint stress groups received a left carotid artery iron chloride3 (FeCl3)-induced thrombosis injury for biological and morphological evaluations at specific timepoints. On day 21 post-stress/injury, the stress had enhanced the arterial thrombi weights and lengths, in addition to harmful alterations of plasma ADAMTS13, von Willebrand factor, and plasminogen activation inhibitor-1, plus injured-artery endothelial loss and CTSK protein/mRNA expression. The stressed CTSK+/+ mice had increased levels of injured arterial cleaved Notch1, Hes1, cleaved caspase8, matrix metalloproteinase-9/-2, angiotensin type 1 receptor, galactin3, p16IN4A, p22phox, gp91phox, intracellular adhesion molecule-1, TNF-α, MCP-1, and TLR-4 proteins and/or genes. Pharmacological and genetic inhibitions of CTSK ameliorated the stress-induced thrombus formation and the observed molecular and morphological changes. In cultured HUVECs, CTSK overexpression and silencing respectively increased and mitigated stressed-serum- and H2O2-induced apoptosis associated with apoptosis-related protein changes. Recombinant human CTSK degraded γ-secretase substrate in a dose-dependent manor and activated Notch1 and Hes1 expression upregulation.

CONCLUSIONS

CTSK appeared to contribute to stress-related thrombosis in mice subjected to FeCl3 stress, possibly via the modulation of vascular inflammation, oxidative production and apoptosis, suggesting that CTSK could be an effective therapeutic target for CPS-related thrombotic events in patients with CCVDs.

The effects of different stress on intestinal mucosal barrier and intestinal microecology were discussed based on three typical animal models

Recent studies have revealed that the effect of intestinal microecological disorders on organismal physiology is not limited to the digestive system, which provides new perspectives for microecological studies and new ideas for clinical diagnosis and prevention of microecology-related diseases. Stress triggers impairment of intestinal mucosal barrier function, which could be duplicated by animal models. In this paper, pathological animal models with high prevalence and typical stressors—corresponding to three major stressors of external environmental factors, internal environmental factors, and social psychological factors, respectively exemplified by burns, intestinal ischemia-reperfusion injury (IIRI), and depression models—were selected. We summarized the construction and evaluation of these typical animal models and the effects of stress on the organism and intestinal barrier, as well as systematically discussed the effects of different stresses on the intestinal mucosal barrier and intestinal microecology.

DPP4 as a Potential Candidate in Cardiovascular Disease

The rising prevalence of cardiovascular disease has become a global health concern. The occurrence of cardiovascular disease is the result of long-term interaction of many risk factors, one of which is diabetes. As a novel anti-diabetic drug, DPP4 inhibitor has been proven to be cardiovascular safe in five recently completed cardiovascular outcome trials. Accumulating studies suggest that DPP4 inhibitor has potential benefits in a variety of cardiovascular diseases, including hypertension, calcified aortic valve disease, coronary atherosclerosis, and heart failure. On the one hand, in addition to improving blood glucose control, DPP4 inhibitor is involved in controlling cardiovascular risk factors. On the other hand, DPP4 inhibitor directly regulates the occurrence and progression of cardiovascular diseases through a variety of mechanisms. In this review, we summarize the recent advances of DPP4 in cardiovascular disease, aiming to discuss DPP4 inhibitor as a potential option for cardiovascular therapy.

Nonerythropoietic Erythropoietin Mimetic Peptide ARA290 Ameliorates Chronic Stress-Induced Depression-Like Behavior and Inflammation in Mice

Major depressive disorder (MDD) is a highly prevalent psychiatric disorder. But the treatment of depression remains challenging. Anti-inflammatory treatments frequently produce antidepressant effects. EPO-derived helix-B peptide ARA290 has been reported to retain the anti-inflammatory and tissue-protective functions of EPO without erythropoiesis-stimulating effects. The effects of ARA290 on MDD remain elusive. This study established chronic unpredictable mild stress and chronic social defeat stress mouse models. Daily administration of ARA290 during chronic stress induction in two mouse models ameliorated depression-like behavior, similar to fluoxetine. With marginal effects on peripheral blood hemoglobin and red cells, ARA290 and fluoxetine reversed chronic stress-induced increased frequencies and/or numbers of CD11b+Ly6Ghi neutrophils and CD11b+Ly6Chi monocytes in the bone marrow and meninges. Furthermore, both drugs reversed chronic stress-induced microglia activation. Thus, ARA290 ameliorated chronic stress-induced depression-like behavior in mice through, at least partially, its anti-inflammatory effects.

Novel Insights into the Roles and Mechanisms of GLP-1 Receptor Agonists against Aging-Related Diseases

Aging and aging-related diseases have emerged as increasingly severe health and social problems. Therefore, it is imperative to discover novel and effective therapeutics to delay the aging process and to manage aging-related diseases. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs), one of the classes of antihyperglycemic drugs, have been recommended to manage type 2 diabetes mellitus (T2DM). Moreover, GLP-1 RAs have been shown to protect against oxidative stress, cellular senescence and chronic inflammation, which are widely accepted as the major risk factors of aging. However, their significance in aging or aging-related diseases has not been elucidated. Herein, we explain the underlying mechanisms and protective roles of GLP-1 RAs in aging from a molecular, cellular and phenotypic perspective. We provide novel insights into the broad prospect of GLP-1 RAs in preventing and treating aging-related diseases. Additionally, we highlight the gaps for further studies in clinical applications of GLP-1 RAs in aging-related diseases. This review forms a basis for further studies on the relationship between aging-related diseases and GLP-1 RAs.

Saxagliptin ameliorated the depressive-like behavior induced by chronic unpredictable mild stress in rats: Impact on incretins and AKT/PI3K pathway

Depression is a widespread, withering illness, resulting in a massive personal suffering and economic loss. The chronic exposure to stress may be involved in the etiology of human psychiatric disorders; such as depression. In the current study, the animals were subjected to chronic unpredictable mild stress (CUMS) for 14 days. Saxagliptin (SAXA) is a member of dipeptidyl peptidase-4 (DPP-4) inhibitors class. The current study was the first one to examine the anti-depressive effect of SAXA in an experimental model of CUMS-induced depression in rats and the possible underlying mechanisms. Animals were orally treated with SAXA (0.5, 1 and 2 mg/kg) for 14 days. SAXA treatment reversed the CUMS-induced alterations in the behavioral, biochemical as well as histopathological parameters. Moreover, it hindered the CUMS-induced increase in the oxidative stress, inflammatory, and apoptotic markers. On the other hand, it increased the monoamines levels and the neurogenic brain derived neurotrophic factor (BDNF). In addition, SAXA treatment increased the incretin hormones, glucagon like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), which are linked to the activation of protein kinase B (AKT)/phosphatidylinositol3-kinase (PI3K) pathway. In conclusion, the current study revealed that the modulation of the interplay between the key events involved in depression, including oxidative stress, inflammation, and GLP-1/PI3K/AKT signaling pathway, can explain the anti-depressant activity of SAXA.

Lessons from bariatric surgery: Can increased GLP-1 enhance vascular repair during cardiometabolic-based chronic disease?

Type 2 diabetes (T2D) and obesity represent entangled pandemics that accelerate the development of cardiovascular disease (CVD). Given the immense burden of CVD in society, non-invasive prevention and treatment strategies to promote cardiovascular health are desperately needed. During T2D and obesity, chronic dysglycemia and abnormal adiposity result in systemic oxidative stress and inflammation that deplete the vascular regenerative cell reservoir in the bone marrow that impairs blood vessel repair and exacerbates the penetrance of CVD co-morbidities. This novel translational paradigm, termed 'regenerative cell exhaustion' (RCE), can be detected as the depletion and dysfunction of hematopoietic and endothelial progenitor cell lineages in the peripheral blood of individuals with established T2D and/or obesity. The reversal of vascular RCE has been observed after administration of the sodium-glucose cotransporter-2 inhibitor (SGLT2i), empagliflozin, or after bariatric surgery for severe obesity. In this review, we explore emerging evidence that links improved dysglycemia to a reduction in systemic oxidative stress and recovery of circulating pro-vascular progenitor cell content required for blood vessel repair. Given that bariatric surgery consistently increases systemic glucagon-like-peptide 1 (GLP-1) release, we also focus on evidence that the use of GLP-1 receptor agonists (GLP-1RA) during obesity may act to inhibit the progression of systemic dysglycemia and adiposity, and indirectly reduce inflammation and oxidative stress, thereby limiting the impact of RCE. Therefore, therapeutic intervention with currently-available GLP-1RA may provide a less-invasive modality to reverse RCE, bolster vascular repair mechanisms, and improve cardiometabolic risk in individuals living with T2D and obesity.

Vascular repair and regeneration in cardiometabolic diseases

Chronic cardiometabolic assaults during type 2 diabetes (T2D) and obesity induce a progenitor cell imbalance in the circulation characterized by overproduction and release of pro-inflammatory monocytes and granulocytes from the bone marrow alongside aberrant differentiation and mobilization of pro-vascular progenitor cells that generate downstream progeny for the coordination of blood vessel repair. This imbalance can be detected in the peripheral blood of individuals with established T2D and severe obesity using multiparametric flow cytometry analyses to discern pro-inflammatory vs. pro-angiogenic progenitor cell subsets identified by high aldehyde dehydrogenase activity, a conserved progenitor cell protective function, combined with lineage-restricted cell surface marker analyses. Recent evidence suggests that progenitor cell imbalance can be reversed by treatment with pharmacological agents or surgical interventions that reduce hyperglycaemia or excess adiposity. In this state-of-the-art review, we present current strategies to assess the progression of pro-vascular regenerative cell depletion in peripheral blood samples of individuals with T2D and obesity and we summarize novel clinical data that intervention using sodium-glucose co-transporter 2 inhibition or gastric bypass surgery can efficiently restore cell-mediated vascular repair mechanisms associated with profound cardiovascular benefits in recent outcome trials. Collectively, this thesis generates a compelling argument for early intervention using current pharmacological agents to prevent or restore imbalanced circulating progenitor content and maintain vascular regenerative cell trafficking to sites of ischaemic damage. This conceptual advancement may lead to the design of novel therapeutic approaches to prevent or reverse the devastating cardiovascular comorbidities currently associated with T2D and obesity.

Pleiotropic Benefits of DPP-4 Inhibitors Beyond Glycemic Control

Dipeptidyl peptidase (DPP)-4 inhibitors are oral anti-diabetic medications that block the activity of the ubiquitous enzyme DPP-4. Inhibition of this enzyme increases the level of circulating active glucagon-like peptide (GLP)-1 secreted from L-cells in the small intestine. GLP-1 increases the glucose level, dependent on insulin secretion from pancreatic β-cells; it also decreases the abnormally increased level of glucagon, eventually decreasing the blood glucose level in patients with type 2 diabetes. DPP-4 is involved in many physiological processes other than the degradation of GLP-1. Therefore, the inhibition of DPP-4 may have numerous effects beyond glucose control. In this article, we review the pleiotropic effects of DPP-4 inhibitors beyond glucose control, including their strong beneficial effects on the stress induced accelerated senescence of vascular cells, and the possible clinical implications of these effects.

Lead in Synergism With IFNγ Acts on Bone Marrow-Resident Macrophages to Increase the Quiescence of Hematopoietic Stem Cells

Lead (Pb) is a highly toxic heavy metal that broadly exists in our living environment. Although Pb has been shown to influence the development of immune cells, to date, the impact of Pb on hematopoietic stem cells (HSCs) in the bone marrow (BM) remains unknown. As people are ubiquitously exposed to Pb and HSC are essential for human health, understanding the impact of Pb on HSC is significant for public health. In this study, we found that wild-type B6 mice treated with 1250 ppm Pb, but not 125 ppm Pb via drinking water for 8 weeks had increased quiescence of HSC in the BM. Functional analyses demonstrated that wild-type mice treated with 1250 ppm Pb had increased potential for HSC to repopulate the immune system and engraft to the niche in the BM under a competitive chimeric microenvironment of lethally irradiated recipients. Moreover, we found that Pb-increased quiescence of HSC critically relied on a synergetic action of Pb and interferon γ (IFNγ) on BM-resident macrophages (BM-MΦ), but not a direct action of Pb on HSC. Specifically, in steady state, BM-MΦ promoted HSC proliferation; and upon Pb treatment, IFNγ was induced in the BM, and thereafter Pb in synergism with IFNγ acted on BM-MΦ to cause BM-MΦ to become suppressive for HSC proliferation, thus leading to increased quiescence of HSC. Our study suggests that Pb increased the quiescence of HSC via a synergetic action of Pb and IFNγ on BM-MΦ, which was previously unrecognized toxicity of Pb.

Dipeptidyl peptidase-4 inhibition prevents lung injury in mice under chronic stress via the modulation of oxidative stress and inflammation

Exposure to chronic psychosocial stress is a risk factor for various pulmonary diseases. In view of the essential role of dipeptidyl peptidase 4 (DPP4) in animal and human lung pathobiology, we investigated the role of DPP4 in stress-related lung injury in mice. Eight-week-old male mice were randomly divided into a non-stress group and a 2-week immobilization stress group. Non-stress control mice were left undisturbed. The mice subjected to immobilized stress were randomly assigned to the vehicle or the DPP4 inhibitor anagliptin for 2 weeks. Chronic stress reduced subcutaneous and inguinal adipose volumes and increased blood DPP4 levels. The stressed mice showed increased levels in the lungs of genes and/or proteins related to oxidative stress (p67^phox, p47^phox, p22^phox and gp91^phox), inflammation (monocyte chemoattractant protein-1, vascular cell adhesion molecule-1, and intracellular adhesion molecule-1), apoptosis (caspase-3, -8, -9), senescence (p16^INK4A, p21, and p53) and proteolysis (matrix metalloproteinase-2 to -9, cathepsin S/K, and tissue inhibitor of matrix metalloproteinase-1 and -2), and reduced levels of eNOS, Sirt1, and Bcl-2 proteins; and these effects were reversed by genetic and pharmacological inhibitions of DPP4. We then exposed human umbilical vein endothelial cells in vitro to hydrogen peroxide; anagliptin treatment was also observed to mitigate oxidative and inflammatory molecules in this setting. Anagliptin can improve lung injury in stressed mice, possibly by mitigating vascular inflammation, oxidative stress production, and proteolysis. DPP4 may become a new therapeutic target for chronic psychological stress-related lung disease in humans and animals.

Deficiency of cysteinyl cathepsin K suppresses the development of experimental intimal hyperplasia in response to chronic stress

BACKGROUND

Chronic psychological stress (CPS) is linked to cardiovascular disease initiation and progression. Given that cysteinyl cathepsin K (CatK) participates in vascular remodeling and atherosclerotic plaque growth in several animal models, we investigated the role of CatK in the development of experimental neointimal hyperplasia in response to chronic stress.

METHODS AND RESULTS

At first, male wild-type (CatK) mice that underwent carotid ligation injury were subjected to chronic immobilization stress. On postoperative and stressed day 14, the results demonstrated that stress accelerated injury-induced neointima hyperplasia. On day 4, stressed mice showed following: increased levels of monocyte chemoattractant protein-1, gp91phox, toll-like receptor-2 (TLR2), TLR4, and CatK mRNAs or/and proteins, oxidative stress production, aorta-derived smooth muscle cell (SMC) migration, and macrophage infiltration as well as targeted intracellular proliferating-related molecules. Stressed mice showed increased matrix metalloproteinase-2 (MMP-2) and MMP-9 mRNA expressions and activities and elastin disruption in the injured carotid arteries. Second, CatK and CatK deficiency (CatK) mice received ligation injury and stress to explore the role of CatK. The stress-induced harmful changes were prevented by CatK. Finally, CatK mice that had undergone ligation surgery were randomly assigned to one of two groups and administered vehicle or CatK inhibitor for 14 days. Pharmacological CatK intervention produced a vascular benefit.

CONCLUSION

These data indicate that CatK deletion protects against the development of experimental neointimal hyperplasia via the attenuation of inflammatory overaction, oxidative stress production, and VSMC proliferation, suggesting that CatK is a novel therapeutic target for the management of CPS-related restenosis after intravascular intervention therapies.

Increased dipeptidyl peptidase-4 accelerates chronic stress-related thrombosis in a mouse carotid artery model

OBJECTIVE

Exposure to chronic psychosocial stress is a risk factor for metabolic cardiovascular disorders. Given that dipeptidyl peptidase-4 (DPP-4) has an important role in human pathobiology, we investigated the role of DPP-4 in stress-related thrombosis in mice, focusing on oxidative stress and the von Willebrand factor (vWF)-cleaving protease ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motif, member 13).

METHODS AND RESULTS

Male mice randomly assigned to nonstress and 2-week immobilized-stress groups underwent iron chloride3 (FeCl3)-induced carotid artery thrombosis surgery for morphological and biochemical studies at specific times. On day 14 post-stress/surgery, stress had enhanced the lengths and weights of arterial thrombi, with alterations of plasma DPP-4, plasminogen activation inhibitor-1 and ADAMTS13. The stressed mice had increased levels of vascular cell adhesion molecule-1, intracellular adhesion molecule-1, monocyte chemoattractant protein-1, gp91phox, p22phox, matrix metalloproteinase-2 (MMP-2), MMP-9, cathepsins S and K mRNAs and/or proteins, and reduced levels of endothelial nitric oxide synthase, catalase and superoxide dismutase-1 mRNAs and/or proteins. Stress also accelerated arterial endothelial cell damage. The DPP-4 inhibitor anagliptin ameliorated the stress-induced targeted molecular and morphological changes and thrombosis. In vitro, DPP-4 inhibition also mitigated the alterations in the targeted ADAMTS13 and other oxidative and inflammatory molecules in human umbilical vein endothelial cells in response to H2O2.

CONCLUSION

DPP-4 inhibition appeared to improve the FeCl3-induced thrombosis in mice that received stress, possibly via the improvement of ADAMTS13 and oxidative stress, suggesting that DPP-4 could become a novel therapeutic target for chronic psychological stress-related thrombotic events in metabolic cardiovascular disorders.

Role of Dipeptidyl Peptidase-4 in Atherosclerotic Cardiovascular Disease in Humans and Animals with Chronic Stress

Exposure to psychosocial stress is a risk factor for cardiovascular disease, including vascular atherosclerosis-based cardiovascular disease (ACVD). Dipeptidyl peptidase-4 (DPP-4) is a complex enzyme that acts as a membrane-anchored cell surface exopeptidase. DPP-4 is upregulated in metabolic and inflammatory cardiovascular disorders. DPP-4 exhibits many physiological and pharmacological functions by regulating its extremely abundant substrates, such as glucagon-like peptide-1 (GLP-1). Over the last 10 years, emerging data have demonstrated unexpected roles of DPP-4 in extracellular and intracellular signaling, immune activation, inflammation, oxidative stress production, cell apoptosis, insulin resistance, and lipid metabolism. This mini-review focuses on recent novel findings in this field, highlighting a DPP-4-mediated regulation of GLP-1-dependent and -independent signaling pathways as a potential therapeutic molecular target in treatments of chronic psychological stress-related ACVD in humans and animals.

An expanded role for dipeptidyl peptidase 4 in cell regulation

PURPOSE OF REVIEW

Dipeptidyl peptidase 4 (DPP4) is a serine protease with diverse regulatory functions in healthy and diseased cells. Much remains unknown about the mechanisms and targets of DPP4. Here we discuss new studies exploring DPP4-mediated cellular regulation, provide an updated list of potential targets of DPP4, and discuss clinical implications of each.

RECENT FINDINGS

Recent studies have sought enhanced efficacy of targeting DPP4's role in regulating hematopoietic stem and progenitor cells for improved clinical application. Further studies have identified DPP4 functions in different cellular compartments and have proposed ways to target this protein in malignancy. These findings, together with an expanded list of putative extracellular, cell surface, and intracellular DPP4 targets, provide insight into new DPP4-mediated cell regulation.

SUMMARY

DPP4 posttranslationally modifies proteins and peptides with essential roles in hematopoietic cell regulation, stem cell transplantation, and malignancy. Targets include secreted signaling factors and may include membrane proteins and transcription factors critical for different hematopoietic functions. Knowing these targets and functions can provide insight into new regulatory roles for DPP4 that may be targeted to enhance transplantation, treat disease, and better understand different regulatory pathways of hematopoiesis.

Aberrant expression of miR-214 is associated with obesity-induced insulin resistance as a biomarker and therapeutic

BACKGROUND

Insulin resistance (IR) in obesity is associated with the occurrence of metabolic and cardiovascular diseases. Dipepidyl peptidase 4 (DPP4) plays a pivotal role during the development of IR, and was found to be a target gene of microRNA-214 (miR-214) in our study. This study sought to assess the expression and clinical value of miR-214 in obese patients with IR, and investigate its therapeutic potential in obese rats and adipocytes with IR.

METHODS

Serum expression of miR-214 in obese patients with or without IR was estimated by quantitative real-time-PCR. A receiver operating characteristic curve was plotted to evaluate the diagnostic value of miR-214 in the patients. Obesity-induced IR animal and cell models were constructed, and the therapeutic ability of miR-214 was explored.

RESULTS

Serum expression of miR-214 was decreased in obese patients compared with the healthy controls, and the lowest expression was observed in the cases with IR. Downregulation of miR-214 was significantly correlated with the serum DPP4 levels and HOMA-IR of the patients upon IR conditions, and was demonstrated to perform diagnostic accuracy for distinguishing obese patients with IR from those without IR. In obesity-associated IR animal and cell models, the downregulation of miR-214 was also been detected. According to the measurement of glucose and insulin tolerance and glucose uptake abilities, we found that the overexpression of miR-214 could be used to alleviate IR in the IR models, especially when collaboratively used with DPP4 inhibitor vildagliptin.

CONCLUSION

All data revealed that miR-214, as a regulator of DPP4, is decreased in obese patients with IR and may serve as a diagnostic biomarker. The upregulation of miR-214 could improve IR in obese rats and adipocytes, indicating that miR-214 has the therapeutic potential for obesity and IR.

Type 2 Diabetes Mellitus non-surgical remission: A possible mission

Background

Remission of Type 2 Diabetes Mellitus (DM) has been observed throughout the last few years, yet factors associated with remission through non-surgical approaches are still unclear. So, the factors associated with type 2 DM remission were investigated.

Methods

Out 670 patients, 63 patients gained non-surgical remission of type 2 DM (defined according to ADA criteria), and 396 patients served as control matched for age, sex, and BMI. The records of patients who attended Alexandria University Students Hospital between the years 2015 and 2018 were reviewed retrospectively. The collected data at first visit and 1 year after remission were history, examination, HbA1c %, oral glucose tolerance test & fasting blood glucose and lipid profile and type of treatment.

Results

75% of patients were females with mean age 51.5 ± 11.34 years. The mean duration of treatment till remission was 26.4 ± 33.1 months. One year after remission HbA1c & BMI were significantly decreased (P = 0.001, 0.03; respectively). However, cox proportional hazards model & ROC curve analysis showed that age < 50 years, female sex, short duration of diabetes < 5.2 years, intial HbA1c < 8.5%, HDL > 45.6 mg/dl, and initial intervention with lifestyle modification, 2000 mg metformin and 100 mg vildagliptin are the factors associated with remission.

Conclusion

Our mission in type 2 DM female patients < 50 years with short duration of disease < 5.2 years, initial HbA1c < 8.5% and HDL > 45.6 mg/dl, is to achieve diabetes remission by intensive life style modification with daily metformin and vildagliptin.

Cathepsin S Deficiency Mitigated Chronic Stress-Related Neointimal Hyperplasia in Mice

Background Exposure to chronic psychosocial stress is a risk factor for atherosclerosis-based cardiovascular disease. We previously demonstrated the increased expressions of cathepsin S (CatS) in atherosclerotic lesions. Whether CatS participates directly in stress-related neointimal hyperplasia has been unknown. Methods and Results Male wild-type and CatS-deficient mice that underwent carotid ligation injury were subjected to chronic immobilization stress for morphological and biochemical studies at specific times. On day 14 after stress/surgery, stress enhanced the neointima formation. At the early time points, the stressed mice had increased plaque elastin disruption, cell proliferation, macrophage accumulation, mRNA and/or protein levels of vascular cell adhesion molecule-1, angiotensin II type 1 receptor, monocyte chemoattractant protein-1, gp91^phox, stromal cell-derived factor-1, C-X-C chemokine receptor-4, toll-like receptor-2, toll-like receptor-4, SC 35, galectin-3, and CatS as well as targeted intracellular proliferating-related molecules (mammalian target of rapamycin, phosphorylated protein kinase B, and p-glycogen synthase kinase-3α/β). Stress also increased the plaque matrix metalloproteinase-9 and matrix metalloproteinase-2 mRNA expressions and activities and aorta-derived smooth muscle cell migration and proliferation. The genetic or pharmacological inhibition of CatS by its specific inhibitor (Z- FL -COCHO) ameliorated the stressed arterial targeted molecular and morphological changes and stressed aorta-derived smooth muscle cell migration. Both the genetic and pharmacological interventions had no effect on increased blood pressure in stressed mice. Conclusions These results demonstrate an essential role of CatS in chronic stress-related neointimal hyperplasia in response to injury, possibly via the reduction of toll-like receptor-2/toll-like receptor-4-mediated inflammation, immune action, and smooth muscle cell proliferation, suggesting that CatS will be a novel therapeutic target for stress-related atherosclerosis-based cardiovascular disease.

The pretreatment of chronic restraint stress exerts little impact on the progression of heart failure in mice

Stress is a potent risk factor for depression. Chronic stress can exacerbate and induce symptoms of depression. Clinical studies suggested that depressive patients are more likely to develop coronary artery diseases. However, the causal relationship between depression and heart failure progression remains unclear. In this study, we aimed to explore the relevance between stress and heart failure (HF) in a mouse model subjected to chronic restraint stress and left anterior descending coronary artery (LAD) ligation. Mice were restrained for 3 h daily for 21 days and the processes were repeated once 3 months later. After the repeated chronic restraint stress, mice showed dramatically increased immobility time in the forced swim test, indicating a state of despair. Restrained and control mice were further subjected to LAD ligation surgery. Echocardiography was conducted 1 week, 2 weeks, and 1 month afterward. LAD-operated mice showed a significant decrease in the values of left ventricular ejection fraction (LVEF), and there was no difference in the LVEF values between the restrained and control mice. Relevant gene expression, neurotransmitter system, glial activation, and morphology of the heart-brain axis were comprehensively evaluated. We found no overall differences between the restrained and control mice with HF. Our results revealed that the repeated chronic restraint stress may have little effects on the progression of heart failure.

Analysis of the Correlation between the Myocardial Expression of DPP-4 and the Clinical Parameters of Patients with Heart Failure

Dipeptidyl peptidase-4 (DPP-4) inhibitors are widely used as antidiabetic drugs. We recently reported that DPP-4 inhibition has beneficial effects on heart failure (HF) mice model. Furthermore, we confirmed that myocardial DPP-4 activity was significantly increased in HF mice compared with non-HF mice. The aim of this study was to investigate the level of myocardial CD26 (DPP-4) expression and its association to clinical parameters in HF patients.Endomyocardial biopsy (EMB) specimens (n = 33) were obtained from HF patients who were admitted to Chiba University Hospital from June 2006 to July 2012. EMB specimens were fixed in formaldehyde and stained with Masson's trichrome staining or with anti-CD26 antibody. Patients were divided into the high CD26 density (CD26-H) or low CD26 density groups (CD26-L). DPP-4 density was compared with blood brain natriuretic peptide (BNP) level and echocardiographic parameters at one year after EMB. Although there were no significant differences in echocardiographic parameters between the CD26-H group and CD26-L group, blood BNP levels were higher in the CD26-H group than in the CD26-L group at one year after EMB. Multivariate regression analysis showed that CD26 density was also an independent determinant of blood BNP levels at one year after EMB.The level of myocardial CD26 expression might be a predictive marker of prognosis in patients with HF.

Gut-Brain Neuroendocrine Signaling Under Conditions of Stress-Focus on Food Intake-Regulatory Mediators

The gut-brain axis represents a bidirectional communication route between the gut and the central nervous system comprised of neuronal as well as humoral signaling. This system plays an important role in the regulation of gastrointestinal as well as homeostatic functions such as hunger and satiety. Recent years also witnessed an increased knowledge on the modulation of this axis under conditions of exogenous or endogenous stressors. The present review will discuss the alterations of neuroendocrine gut-brain signaling under conditions of stress and the respective implications for the regulation of food intake.

Response gene to complement 32 suppresses adipose tissue thermogenic genes through inhibiting β3-adrenergic receptor/mTORC1 signaling

Our previous studies have shown that response gene to complement (RGC)-32 deficiency (Rgc32^-/-) protects mice from diet-induced obesity and increases thermogenic gene expression in adipose tissues. However, the underlying mechanisms by which RGC-32 regulates thermogenic gene expression remain to be determined. In the present study, RGC-32 expression in white adipose tissue (WAT) was suppressed during cold exposure-induced WAT browning. Rgc32^-/- significantly increased thermogenic gene expression in the differentiated stromal vascular fraction (SVF) of inguinal (i)WAT and interscapular brown adipose tissue (BAT). Rgc32^-/- and cold exposure regulated a common set of genes in iWAT, as shown by RNA sequencing data. Pathway enrichment analyses showed that Rgc32^-/- down-regulated PI3K/Akt signaling-related genes. Akt phosphorylation was also consistently decreased in Rgc32^-/- iWAT, which led to an increase in β3-adrenergic receptor (β3-AR) expression and subsequent activation of mammalian target of rapamycin complex (mTORC)-1. β3-AR antagonist SR 59230A and mTORC1 inhibitor rapamycin blocked Rgc32^-/--induced thermogenic gene expression in both iWAT and interscapular BAT. These results indicate that RGC-32 suppresses adipose tissue thermogenic gene expression through down-regulation of β3-AR expression and mTORC1 activity via a PI3K/Akt-dependent mechanism.-Chen, S., Mei, X., Yin, A., Yin, H., Cui, X.-B., Chen, S.-Y. Response gene to complement 32 suppresses adipose tissue thermogenic genes through inhibiting β3-adrenergic receptor/mTORC1 signaling.

Dose rectification of an imbalance between DPP4 and GLP-1 ameliorates chronic stress-related vascular aging and atherosclerosis?

Exposure to psychosocial stress is a risk factor for cardiovascular disease, including vascular aging and regeneration. Dipeptidyl peptidase-4 (DPP-4) exerts many physiological and pharmacological functions by regulating its extremely abundant substrates [eg., glucagon-like peptide-1 (GLP-1), stromal cell-derived factor-1α/C-X-C chemokine receptor type-4, etc.]. Over the past decade, emerging data has revealed unexpected roles for DPP-4 and GLP-1 in intracellular signaling, oxidative stress production, lipid metabolism, cell apoptosis, immune activation, insulin resistance, and inflammation. This mini review focuses on recent findings in this field, highlighting an imbalance between DPP4 and GLP-1 as a potential therapeutic target in the management of vascular aging and atherosclerosis in animals under experimental stress conditions.

Chronic Psychological Stress Accelerates Vascular Senescence and Impairs Ischemia-Induced Neovascularization: The Role of Dipeptidyl Peptidase-4/Glucagon-Like Peptide-1-Adiponectin Axis

BACKGROUND

Exposure to psychosocial stress is a risk factor for cardiovascular disease, including vascular aging and regeneration. Given that dipeptidyl peptidase-4 (DPP4) regulates several intracellular signaling pathways associated with the glucagon-like peptide-1 (GLP-1) metabolism, we investigated the role of DPP4/GLP-1 axis in vascular senescence and ischemia-induced neovascularization in mice under chronic stress, with a special focus on adiponectin -mediated peroxisome proliferator activated receptor-γ/its co-activator 1α (PGC-1α) activation.

METHODS AND RESULTS

Seven-week-old mice subjected to restraint stress for 4 weeks underwent ischemic surgery and were kept under immobilization stress conditions. Mice that underwent ischemic surgery alone served as controls. We demonstrated that stress impaired the recovery of the ischemic/normal blood-flow ratio throughout the follow-up period and capillary formation. On postoperative day 4, stressed mice showed the following: increased levels of plasma and ischemic muscle DPP4 and decreased levels of GLP-1 and adiponectin in plasma and phospho-AMP-activated protein kinase α (p-AMPKα), vascular endothelial growth factor, peroxisome proliferator activated receptor-γ, PGC-1α, and Sirt1 proteins and insulin receptor 1 and glucose transporter 4 genes in the ischemic tissues, vessels, and/or adipose tissues and numbers of circulating endothelial CD31+/c-Kit+ progenitor cells. Chronic stress accelerated aortic senescence and impaired aortic endothelial sprouting. DPP4 inhibition and GLP-1 receptor activation improved these changes; these benefits were abrogated by adiponectin blocking and genetic depletion.

CONCLUSIONS

These results indicate that the DPP4/GLP-1-adiponectin axis is a novel therapeutic target for the treatment of vascular aging and cardiovascular disease under chronic stress conditions.

Exenatide mitigated diet-induced vascular aging and atherosclerotic plaque growth in ApoE-deficient mice under chronic stress

BACKGROUND AND AIMS

Exposure to psychosocial stress is a risk factor for cardiovascular disorders. Because the glucagon-like peptide-1 (GLP-1) receptor (GLP-1R) agonist prevents cardiovascular injury, we investigated the beneficial effects and mechanism of the GLP-1 analogue exenatide on stress-related vascular senescence and atherosclerosis in apolipoprotein E-deficient (ApoE^-/-) mice fed a high-fat (HF) diet.

METHODS

ApoE^-/- mice fed the HF diet were assigned to non-stressed and immobilized-stress groups for 12 weeks. Mice fed the HF diet were divided into 2 groups and administered vehicle or exenatide for 12 weeks under stress conditions.

RESULTS

Chronic stress enhanced vascular endothelial senescence and atherosclerotic plaque growth. The stress increased the levels of plasma depeptidyl peptidase-4 activity and decreased the levels of plasma GLP-1 and both plasma and adipose adiponectin (APN). As compared with the mice subjected to stress alone, the exenatide-treated mice had decreased plaque microvessel density, macrophage accumulation, broken elastin, and enhanced plaque collagen volume, and lowered levels of peroxisome proliferator-activated receptor-α, gp91phox osteopontin, C-X-C chemokine receptor-4, toll-like receptor-2 (TLR2), TLR4, and cathepsins K, L, and S mRNAs and/or proteins. Exenatide reduced aortic matrix metalloproteinase-9 (MMP-9) and MMP-2 gene expression and activities. Exenatide also stimulated APN expression of preadipocytes and inhibited ox-low density lipoprotein-induced foam cell formation of monocytes in stressed mice.

CONCLUSIONS

These results indicate that the exenatide-mediated beneficial vascular actions are likely attributable, at least in part, to the enhancement of APN production and the attenuation of plaque oxidative stress, inflammation, and proteolysis in ApoE^-/- mice under chronic stress.