Expression of asprosin in rat hepatic, renal, heart, gastric, testicular and brain tissues and its changes in a streptozotocin-induced diabetes mellitus model

Asprosin contributes to vascular remodeling in hypertensive rats via superoxide signaling

OBJECTIVE

Proliferation and migration of vascular smooth muscle cells (VSMCs) contribute to vascular remodeling. Asprosin, a newly discovered protein hormone, is involved in metabolic diseases. Little is known about the roles of asprosin in cardiovascular diseases. This study focused on the role and mechanism of asprosin on VSMC proliferation and migration, and vascular remodeling in a rat model of hypertension.

METHODS AND RESULTS

VSMCs were obtained from the aortic media of 8-week-old male Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). Asprosin was upregulated in the VSMCs of SHR. For in vitro studies, asprosin promoted VSMC proliferation and migration of WKY and SHR, and increased Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activity, NOX1/2/4 protein expressions and superoxide production. Knockdown of asprosin inhibited the proliferation, migration, NOX activity, NOX1/2 expressions and superoxide production in the VSMCs of SHR. The roles of asprosin in promoting VSMC proliferation and migration were not affected by hydrogen peroxide scavenger, but attenuated by superoxide scavenger, selective NOX1 or NOX2 inhibitor. Toll-like receptor 4 (TLR4) was upregulated in SHR, TLR4 knockdown inhibited asprosin overexpression-induced proliferation, migration and oxidative stress in VSMCs of WKY and SHR. Asprosin was upregulated in arteries of SHR, and knockdown of asprosin in vivo not only attenuated oxidative stress and vascular remodeling in aorta and mesentery artery, but also caused a subsequent persistent antihypertensive effect in SHR.

CONCLUSIONS

Asprosin promotes VSMC proliferation and migration via NOX-mediated superoxide production. Inhibition of endogenous asprosin expression attenuates VSMC proliferation and migration, and vascular remodeling of SHR.

Intervention of Asprosin Attenuates Oxidative Stress and Neointima Formation in Vascular Injury

Aims: Asprosin, a newly discovered hormone, is linked to insulin resistance. This study shows the roles of asprosin in vascular smooth muscle cell (VSMC) proliferation, migration, oxidative stress, and neointima formation of vascular injury. Methods: Mouse aortic VSMCs were cultured, and platelet-derived growth factor-BB (PDGF-BB) was used to induce oxidative stress, proliferation, and migration in VSMCs. Vascular injury was induced by repeatedly moving a guidewire in the lumen of the carotid artery in mice. Results: Asprosin overexpression promoted VSMC oxidative stress, proliferation, and migration, which were attenuated by toll-like receptor 4 (TLR4) knockdown, antioxidant (N-Acetylcysteine, NAC), NADPH oxidase 1 (NOX1) inhibitor ML171, or NOX2 inhibitor GSK2795039. Asprosin overexpression increased NOX1/2 expressions, whereas asprosin knockdown increased heme oxygenase-1 (HO-1) and NADPH quinone oxidoreductase-1 (NQO-1) expressions. Asprosin inhibited nuclear factor E2-related factor 2 (Nrf2) nuclear translocation. Nrf2 activator sulforaphane increased HO-1 and NQO-1 expressions and prevented asprosin-induced NOX1/2 upregulation, oxidative stress, proliferation, and migration. Exogenous asprosin protein had similar roles to asprosin overexpression. PDGF-BB increased asprosin expressions. PDGF-BB-induced oxidative stress, proliferation, and migration were enhanced by Nrf2 inhibitor ML385 but attenuated by asprosin knockdown. Vascular injury increased asprosin expression. Local asprosin knockdown in the injured carotid artery promoted HO-1 and NQO-1 expressions but attenuated the NOX1 and NOX2 upregulation, oxidative stress, neointima formation, and vascular remodeling in mice. Innovation and Conclusion: Asprosin promotes oxidative stress, proliferation, and migration of VSMCs via TLR4-Nrf2-mediated redox imbalance. Inhibition of asprosin expression attenuates VSMC proliferation and migration, oxidative stress, and neointima formation in the injured artery. Asprosin might be a promising therapeutic target for vascular injury.

Asprosin promotes vascular inflammation via TLR4-NFκB-mediated NLRP3 inflammasome activation in hypertension

Objective

and design Mild vascular inflammation promotes the pathogenesis of hypertension. Asprosin, a newly discovered adipokine, is closely associated with metabolic diseases. We hypothesized that asprosin might led to vascular inflammation in hypertension via NLRP3 inflammasome formation. This study shows the importance of asprosin in the vascular inflammation of hypertension.

Methods

Primary vascular smooth muscle cells (VSMCs) were obtained from the aorta of animals, including spontaneously hypertensive rats (SHR), Wistar-Kyoto rats (WKY), NLRP3-/- and wild-type mice. Studies were performed in VSMCs in vitro, as well as WKY and SHR in vivo.

Results

Asprosin expressions were up-regulated in VSMCs and media of arteries in SHR. Asprosin overexpression promoted NLRP3 inflammasome activation via Toll-like receptor 4 (TLR4), accompanied with activation of NFκB signaling pathway in VSMCs. Exogenous asprosin protein showed similar roles in promoting NLRP3 inflammasome activation. Knockdown of asprosin restrained NLRP3 inflammasome and p65-NFκB activation in VSMCs of SHR. NLRP3 inhibitor MCC950 or NFκB inhibitor BAY11-7082 attenuated asprosin-caused VSMC proliferation and migration. Asprosin-induced interleukin-1β production, proliferation and migration were attenuated in NLRP3-/- VSMCs. Local asprosin knockdown in common carotid artery of SHR attenuated inflammation and vascular remodeling.

Conclusions

Asprosin promoted NLRP3 inflammasome activation in VSMCs by TLR4-NFκB pathway, and thereby stimulates VSMCs proliferation, migration, and vascular remodeling of SHR.

Plasma Asprosin Concentrations are Associated with Progression of Diabetic Kidney Disease

Purpose

To explore the expression of asprosin in subjects with pre-DKD and DKD and to analyze its relationship with kidney injury, inflammation, and glucose and lipid metabolism.

Methods

Based on urine albumin:creatinine ratio (UACr), participants were divided into DM, pre-DKD, and DKD groups. Relevant human physiological and biochemical parameters were detected in the three groups.

Results

We found relatively higher levels of asprosin in both pre-DKD and DKD groups than the DM group. Moreover, data from the Nephroseq database support increased gene expression of asprosin in kidney tissue from DKD patients. Further correlation analysis revealed that the plasma asprosin level was positively correlated with age, waist circumference, waist:hip ratio, systolic blood pressure, creatinine, UACr, triglycerides, HDL-c, fasting insulin, HOMA-IR, and the inflammatory marker G3P and negatively associated with eGFR. Multiple logistical regression analysis showed that asprosin concentration was significantly associated with pre-DKD and DKD after adjusting for sex, age, BMI, WHR, and HOMA-IR, while this correlation was lost after controlling for G3P.

Conclusion

Plasma asprosin is associated with kidney injury in diabetic conditions, and this association might be connected through inflammatory response. Further studies are needed to assess the role and mechanism of asprosin in DKD.

Effect of Boric Acid on Metabolic Peptides and Some Biochemical Parameters in Experimental Diabetic Rats

Boron (B) is an element that has recently been wondered and researched in many fields, especially due to its effects on energy metabolism. The aim of this study is to evaluate the effect of boric acid (BA) on newly discovered energy metabolism peptides that have not been studied before. In this study, the effects of 15 mg/kg of BA were evaluated in 24 Wistar rats. Groups were named as control group, 15 mg/kg BA group, streptozotocin (STZ)-induced experimental diabetic group, and STZ-induced experimental diabetic + 15 mg/kg BA administered group (STZ+15 mg/kg BA). Serum asprosin, nesfatin-1, preptin, insulin, total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), aspartate transaminase (AST), alanine transaminase (ALT), and glucose analyses were performed. In this study, the increase in glucose, TG, TC, LDL-C levels, and AST, ALT activities in STZ-induced groups were reduced with BA administration. While HDL-C level significantly decreased in the STZ group, the level approached the control group values after BA administration (p<0.001). As for peptides, although there was a statistically significant increase after 15 mg/kg BA administration, these levels did not approach the control group values (p<0.001). According to the findings, STZ-induced diabetes mellitus and the biochemical processes that develop accordingly change correlatively. This study showed that BA is effective in energy metabolism.

Elevated Asprosin Levels in Breast Cancer: Insights from a Comparative Study

Background: Breast cancer (BC) is the most common type of cancer in women. Diagnosis in the early stage is very important for cancer treatment. There is no good biomarker to diagnose BC in T1-T2 or N0 stage. This study aimed to evaluate asprosin (ASP) levels of BC compared with non-cancer. Materials and Methods: An enzyme-linked immunosorbent assay was used to evaluate serum ASP levels in 40 patients with BC and 40 healthy women. The cancer group included T1-T4, N1-N3, and M0-M1 patients. T stages were divided into groups as T1-T2 and T3-T4. N stages were divided into groups as N (0) and N (+). Results: ASP showed good discrimination (area under the curve = 0.767, 95% confidence interval: 0.657-0.878) between the BC group and the healthy group and acceptable discriminating ability (sensitivity = 0.825; specificity = 0.750) at the optimal cutoff value of 1.82 ng/mL. ASP indicated no difference for T, N, and M stages (p = 0.919, p = 0.859, and p = 0.225, respectively). There was a significant difference between grades within cancer patients in terms of ASP (p = 0.025). Conclusions: These findings provide evidence of a potential association between elevated ASP levels and the presence of BC. The observed higher levels of ASP in women with BC compared with healthy individuals suggest that ASP could potentially serve as a biomarker for distinguishing between the two groups. These results may contribute to our understanding of the potential role of ASP in BC detection and highlight its potential as a diagnostic marker. Further studies are required to establish whether ASP can be used to diagnose BC.

Effects of Vitamin D on Asprosin Immunoreactivity Against Cyclophosphamide-Induced Liver Injury in Rats

Background Cyclophosphamide (CP), commonly used as an anticarcinogenic drug, has the potential to induce detrimental effects on multiple tissues, including the liver. Asprosin, which is a glucogenic adipokine, induces the liver to secrete glucose, thus contributing to the maintenance of homeostasis. This study aims to investigate the immunoreactivity of asprosin in the liver tissue of rats exposed to CP administration, as well as the changes in its levels due to the supplementation of Vitamin D (Vit D). Materials and methods Four experimental groups were formed, including control, Vit D (200 IU/kg), CP (200 mg/kg), and Vit D+ CP. Histopathological analysis was carried out by employing staining methods on liver tissues. These techniques encompassed the application of hematoxylin-eosin (H&E), Masson's trichrome, and periodic acid Schiff (PAS). Through the application of spectrophotometric methods, concentrations of malondialdehyde (MDA), total antioxidant status (TAS), total oxidant status (TOS), and asprosin were determined. Furthermore, apoptotic cells were identified by the terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) method, and the asprosin immunoreactivity was determined by immunohistochemistry. Results Under light microscope examination, the histopathological damage was found to be more notable in the CP group compared to the control group. Moreover, a decrease was observed in serum and tissue asprosin levels, while an increase was noted in the count of apoptotic cells, along with elevated MDA and TOS levels. However, in the CP+Vit D group, Vit D administration alleviated histopathological damage. Notably, there were significant increases in TAS and asprosin levels, accompanied by reductions in both MDA and TOS levels. Conclusions The effect of CP on liver tissue was observed to result in damage and a reduction in asprosin levels. Vit D supplementation revealed elevated asprosin levels and a distinct protective effect on the tissue. Considering the association between asprosin and liver injury induced by CP, further research is needed to elucidate the mechanisms that underlie the effect of asprosin on tissues. When combined with Vit D, asprosin holds promise for potential clinical applications as a therapeutic target.

Asprosin, a novel glucogenic adipokine: a potential therapeutic implication in diabetes mellitus

OBJECTIVES

We aimed to investigate the effects of asprosin on diabetes with a focus on serum glucose, irisin, ghrelin, leptin levels and hepatic levels of triglycerides (TG), cholesterol, low-density lipoprotein (LDL).

METHODS

Asprosin (10 µg/kg) was administered intraperitoneally four times at 3-day intervals and then blood and hepatic parameters above mentioned were investigated in control and diabetic mice.

RESULTS

The administration of asprosin increased blood glucose level in healthy animals (p = .05) whereas it did not change blood glucose level in diabetic animals. In addition, while asprosin decreased irisin level and increased ghrelin level, it did not change leptin level in diabetic mice. Therewithal, asprosin decreased the increasing levels in hepatic TG, cholesterol, and LDL in diabetic mice.

CONCLUSIONS

Our novel findings implicate that asprosin may be a target molecule in preventing the development and complications of diabetes.

Adipokines in atherosclerosis: unraveling complex roles

Adipokines are biologically active factors secreted by adipose tissue that act on local and distant tissues through autocrine, paracrine, and endocrine mechanisms. However, adipokines are believed to be involved in an increased risk of atherosclerosis. Classical adipokines include leptin, adiponectin, and ceramide, while newly identified adipokines include visceral adipose tissue-derived serpin, omentin, and asprosin. New evidence suggests that adipokines can play an essential role in atherosclerosis progression and regression. Here, we summarize the complex roles of various adipokines in atherosclerosis lesions. Representative protective adipokines include adiponectin and neuregulin 4; deteriorating adipokines include leptin, resistin, thrombospondin-1, and C1q/tumor necrosis factor-related protein 5; and adipokines with dual protective and deteriorating effects include C1q/tumor necrosis factor-related protein 1 and C1q/tumor necrosis factor-related protein 3; and adipose tissue-derived bioactive materials include sphingosine-1-phosphate, ceramide, and adipose tissue-derived exosomes. However, the role of a newly discovered adipokine, asprosin, in atherosclerosis remains unclear. This article reviews progress in the research on the effects of adipokines in atherosclerosis and how they may be regulated to halt its progression.

Developmental and hormonal regulation of FBN1 and OR4M1 mRNA in bovine granulosa cells

Recent studies have reported hormonal regulation of expression of fibrillin 1 (FBN1), the gene that encodes asprosin, in bovine theca cells, however, hormonal regulation of gene expression of FBN1 and the asprosin receptor, olfactory receptor 4M1 (OR4M1), has not been evaluated in granulosa cells (GC). This study was designed to characterize FBN1 and OR4M1 gene expression in GC during development of bovine dominant ovarian follicles, and to determine the hormonal regulation of FBN1 and OR4M1 mRNA expression in GC. GC FBN1 mRNA abundance was greater (P < 0.05) in medium (5.1-8 mm) estrogen inactive (EI) follicles than in large (>8.1 mm) or small (1-5 mm) EI follicles. In comparison, GC OR4M1 mRNA abundance was greater (P < 0.05) in small EI follicles than in large or medium EI follicles. Abundance of OR4M1 mRNA in GC of follicles collected on days 3 to 4 (early growth phase) and on days 5 to 6 (late growth phase) was similar, whereas FBN1 mRNA abundance was greater (P < 0.05) on days 5 to 6 vs days 3 to 4. Hormonal regulators for FBN1 mRNA abundance in cultured small-follicle GC were identified: TGFβ1 causing a 2.45-fold increase, WNT3A causing a 1.45-fold increase, and IGF1 causing a 65% decrease. Steroids, leptin, insulin, growth hormone, follicle stimulating hormone, fibroblast growth factor 9 and epidermal growth factor had no effect on FBN1 mRNA abundance. Abundance of OR4M1 mRNA in GC was regulated by progesterone with 3.55-fold increase, but other hormones did not affect GC OR4M1 mRNA abundance. Findings indicate that both FBN1 and OR4M1 gene expression are hormonally and developmentally regulated in bovine follicles, and thus may affect asprosin production and its subsequent role in ovarian follicular function in cattle.

Can the new adipokine asprosin be a metabolic troublemaker for cardiovascular diseases? A state-of-the-art review

Adipokines play a significant role in cardiometabolic diseases. Asprosin, a newly discovered adipokine, was first identified as a glucose-raising protein hormone. Asprosin also stimulates appetite and regulates glucose and lipid metabolism. Its identified receptors so far include Olfr734 and Ptprd. Clinical studies have found that asprosin may be associated with cardiometabolic diseases. Asprosin may have diagnostic and therapeutic potential in obesity, diabetes, metabolic syndrome and atherosclerotic cardiovascular diseases. Herein, the structure, receptors, and functions of asprosin and its relationship with cardiometabolic diseases are summarized based on recent findings.

Rodent models for diabetes

Diabetes mellitus (DM) is associated with many health complications and is potentially a morbid condition. As prevalence increases at an alarming rate around the world, research into new antidiabetic compounds with different mechanisms is the top priority. Therefore, the preclinical experimental induction of DM is imperative for advancing knowledge, understanding pathogenesis, and developing new drugs. Efforts have been made to examine recent literature on the various induction methods of Type I and Type II DM. The review summarizes the different in vivo models of DM induced by chemical, surgical, and genetic (immunological) manipulations and the use of pathogens such as viruses. For good preclinical assessment, the animal model must exhibit face, predictive, and construct validity. Among all reported models, chemically induced DM with streptozotocin was found to be the most preferred model. However, the purpose of the research and the outcomes to be achieved should be taken into account. This review was aimed at bringing together models, benefits, limitations, species, and strains. It will help the researcher to understand the pathophysiology of DM and to choose appropriate animal models.

Asprosin in health and disease, a new glucose sensor with central and peripheral metabolic effects

Adipose tissue malfunction leads to altered adipokine secretion which might consequently contribute to an array of metabolic diseases spectrum including obesity, diabetes mellitus, and cardiovascular disorders. Asprosin is a novel diabetogenic adipokine classified as a caudamin hormone protein. This adipokine is released from white adipose tissue during fasting and elicits glucogenic and orexigenic effects. Although white adipose tissue is the dominant source for this multitask adipokine, other tissues also may produce asprosin such as salivary glands, pancreatic B-cells, and cartilage. Significantly, plasma asprosin levels link to glucose metabolism, lipid profile, insulin resistance (IR), and β-cell function. Indeed, asprosin exhibits a potent role in the metabolic process, induces hepatic glucose production, and influences appetite behavior. Clinical and preclinical research showed dysregulated levels of circulating asprosin in several metabolic diseases including obesity, type 2 diabetes mellitus (T2DM), polycystic ovarian syndrome (PCOS), non-alcoholic fatty liver (NAFLD), and several types of cancer. This review provides a comprehensive overview of the asprosin role in the etiology and pathophysiological manifestations of these conditions. Asprosin could be a promising candidate for both novel pharmacological treatment strategies and diagnostic tools, although developing a better understanding of its function and signaling pathways is still needed.

Fibrillin-1 and asprosin, novel players in metabolic syndrome

Fibrillin-1 is a major component of the extracellular microfibrils, where it interacts with other extracellular matrix proteins to provide elasticity to connective tissues, and regulates the bioavailability of TGFβ family members. A peptide consisting of the C-terminal 140 amino acids of fibrillin-1 has recently been identified as a glucogenic hormone, secreted from adipose tissue during fasting and targeting the liver to release glucose. This fragment, called asprosin, also signals in the hypothalamus to stimulate appetite. Asprosin levels are correlated with many of the pathologies indicative of metabolic syndrome, including insulin resistance and obesity. Previous studies and reviews have addressed the therapeutic potential of asprosin as a target in obesity, diabetes and related conditions without considering mechanisms underlying the relationship between generation of asprosin and expression of the much larger fibrillin-1 protein. Profibrillin-1 undergoes obligatory cleavage at the cell surface as part of its assembly into microfibrils, producing the asprosin peptide as well as mature fibrillin-1. Patterns of FBN1 mRNA expression are inconsistent with the necessity for regulated release of asprosin. The asprosin peptide may be protected from degradation in adipose tissue. We present evidence for an alternative possibility, that asprosin mRNA is generated independently from an internal promoter within the 3' end of the FBN1 gene, which would allow for regulation independent of fibrillin-synthesis and is more economical of cellular resources. The discovery of asprosin opened exciting possibilities for treatment of metabolic syndrome related conditions, but there is much to be understood before such therapies could be introduced into the clinic.

Aqueous Ethanolic Extract of Adiantum incisum Forssk. Protects against Type 2 Diabetes Mellitus via Attenuation of α-Amylase and Oxidative Stress

Purpose : This study was designed to investigate the antidiabetic effects of the aqueous ethanolic extract of Adiantum incisum Forssk. whole plant (AE-AI) in order to validate the folkloric claim. Methods : Streptozotocin (STZ) was used to induce type 2 diabetes mellitus (TII DM) in male Sprague-Dawley rats. STZ-induced diabetic rats were later treated orally with either AE-AI (125, 250, and 500 mg/kg) or glibenclamide for 35 days. Blood glucose levels were measured weekly and on day 35, animals were sacrificed, and blood samples and tissues were harvested for subsequent antioxidant and histopathological analyses. AE-AI was also analyzed in vitro for phytochemical, antioxidant, and α-amylase inhibitory assays. Results : The phytochemical screening of AE-AI confirmed the presence of essential bioactive compounds like cardiac glycosides, flavonoids, phenolic compounds, saponins, and fixed oils. AE-AI demonstrated abundant amounts of total phenolic and flavonoid contents and displayed prominent antioxidant activity as assessed via DPPH, phosphomolybdate, and nitric oxide scavenging assays. AE-AI treatment also showed α-amylase inhibitory activity comparable to acarbose. In addition, AE-AI treatment exhibited a wide margin of safety in rats and dose-dependently reduced STZ-induced blood glucose levels. Moreover, AE-AI increased the levels of GSH, SOD, catalase, and reduced MDA, and therefore prevented pathological effects of STZ on the kidney, liver, and pancreas. The blood glucose regulatory effect and antioxidant activity of AE-AI also aided in normalizing TII DM-mediated dyslipidemias. GC-MS analysis also demonstrated several potential antidiabetic phytoconstituents in AE-AI. Conclusion : These findings reveal that AE-AI possesses certain pharmacologically active compounds that can effectively treat STZ-induced TII DM owing to its antioxidant and α-amylase inhibitory potentials.

Asprosin in the Paraventricular Nucleus Induces Sympathetic Activation and Pressor Responses via cAMP-Dependent ROS Production

Asprosin is a newly discovered adipokine that is involved in regulating metabolism. Sympathetic overactivity contributes to the pathogenesis of several cardiovascular diseases. The paraventricular nucleus (PVN) of the hypothalamus plays a crucial role in the regulation of sympathetic outflow and blood pressure. This study was designed to determine the roles and underlying mechanisms of asprosin in the PVN in regulating sympathetic outflow and blood pressure. Experiments were carried out in male adult SD rats under anesthesia. Renal sympathetic nerve activity (RSNA), mean arterial pressure (MAP), and heart rate (HR) were recorded, and PVN microinjections were performed bilaterally. Asprosin mRNA and protein expressions were high in the PVN. The high asprosin expression in the PVN was involved in both the parvocellular and magnocellular regions according to immunohistochemical analysis. Microinjection of asprosin into the PVN produced dose-related increases in RSNA, MAP, and HR, which were abolished by superoxide scavenger tempol, antioxidant N-acetylcysteine (NAC), and NADPH oxidase inhibitor apocynin. The asprosin promoted superoxide production and increased NADPH oxidase activity in the PVN. Furthermore, it increased the cAMP level, adenylyl cyclase (AC) activity, and protein kinase A (PKA) activity in the PVN. The roles of asprosin in increasing RSNA, MAP, and HR were prevented by pretreatment with AC inhibitor SQ22536 or PKA inhibitor H89 in the PVN. Microinjection of cAMP analog db-cAMP into the PVN played similar roles with asprosin in increasing the RSNA, MAP, and HR, but failed to further augment the effects of asprosin. Pretreatment with PVN microinjection of SQ22536 or H89 abolished the roles of asprosin in increasing superoxide production and NADPH oxidase activity in the PVN. These results indicated that asprosin in the PVN increased the sympathetic outflow, blood pressure, and heart rate via cAMP–PKA signaling-mediated NADPH oxidase activation and the subsequent superoxide production.

Nicotinamide mononucleotide improves spermatogenic function in streptozotocin-induced diabetic mice via modulating the glycolysis pathway

Spermatogenic dysfunction is one of the major secondary complications of diabetes; however, the underlying mechanisms remain ill-defined, and there is no available drug or strategy for the radical treatment of diabetic spermatogenic dysfunction. Therefore, the objective of this study is to investigate the protective effects of nicotinamide mononucleotide (NMN) on testicular spermatogenic function in streptozotocin (STZ)-induced diabetic mice. The results show that oral administration of NMN significantly increases the body and testis weight and the number of sperms. Moreover, the abnormal sperm count and the rate of sperm malformation are significantly decreased compared with the saline-treated diabetic mice. Histological analysis reveals that NMN treatment significantly increases the area and diameter of seminiferous tubules, accompanied by an increased number of spermatogenic cells and sperms. Immunohistochemistry and qRT-PCR results show that NMN increases Bcl-2 expression and decreases Bax expression in the testis. NMN also increases the protein expression of Vimentin and the mRNA expressions of WT1 and GATA4. In addition, qRT-PCR, western blot analysis and immunohistochemistry results also show that NMN increases the expressions of glycolysis-related rate-limiting enzymes including HK2, PKM2, and LDHA. In summary, this study demonstrates the protective effects of NMN on the testis in an STZ-induced diabetic mice model. NMN exerts its protective effects via reducing spermatogenic cell apoptosis by regulating glycolysis of Sertoli cells in diabetic mice. This study provides an experimental basis for the future clinical application of NMN in diabetes-induced spermatogenic dysfunction.

Asprosin inhibits macrophage lipid accumulation and reduces atherosclerotic burden by up-regulating ABCA1 and ABCG1 expression via the p38/Elk-1 pathway

Background

Asprosin, a newly discovered adipokine, is a C-terminal cleavage product of profibrillin. Asprosin has been reported to participate in lipid metabolism and cardiovascular disease, but its role in atherogenesis remains elusive.

Methods

Asprosin was overexpressed in THP-1 macrophage-derived foam cells and apoE^−/− mice using the lentiviral vector. The expression of relevant molecules was determined by qRT-PCR and/or western blot. The intracellular lipid accumulation was evaluated by high-performance liquid chromatography and Oil red O staining. HE and Oil red O staining was employed to assess plaque burden in vivo. Reverse cholesterol transport (RCT) efficiency was measured using [³H]-labeled cholesterol.

Results

Exposure of THP-1 macrophages to oxidized low-density lipoprotein down-regulated asprosin expression. Lentivirus-mediated overexpression of asprosin promoted cholesterol efflux and inhibited lipid accumulation in THP-1 macrophage-derived foam cells. Mechanistic analysis revealed that asprosin overexpression activated p38 and stimulated the phosphorylation of ETS-like transcription factor (Elk-1) at Ser383, leading to Elk-1 nuclear translocation and the transcriptional activation of ATP binding cassette transporters A1 (ABCA1) and ABCG1. Injection of lentiviral vector expressing asprosin diminished atherosclerotic lesion area, increased plaque stability, improved plasma lipid profiles and facilitated RCT in apoE^−/− mice. Asprosin overexpression also increased the phosphorylation of p38 and Elk-1 as well as up-regulated the expression of ABCA1 and ABCG1 in the aortas.

Conclusion

Asprosin inhibits lipid accumulation in macrophages and decreases atherosclerotic burden in apoE^−/− mice by up-regulating ABCA1 and ABCG1 expression via activation of the p38/Elk-1 signaling pathway.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03542-0.

The Effects of Asprosin on Exercise-Intervention in Metabolic Diseases

Fibrillin is the major constituent of extracellular microfibrils, which are distributed throughout connective tissues. Asprosin is derived from the C-terminal region of the FBN1 gene, which encodes profibrillin that undergoes cleavage by furin protein. In response to fasting with low dietary glucose, asprosin is released as a secreted factor from white adipose tissue, and is transported to the liver for the mediation of glucose release into the blood circulation. Through binding to OLFR734, an olfactory G-protein-coupled receptor in liver cells, asprosin induces a glucogenic effect to regulate glucose homeostasis. Bioinformatics analyses revealed that the FBN1 gene is abundantly expressed in human skeletal muscle-derived mesoangioblasts, osteoblast-like cells, and mesenchymal stem cells, indicating that the musculoskeletal system might play a role in the regulation of asprosin expression. Interestingly, recent studies suggest that asprosin is regulated by exercise. This timely review discusses the role of asprosin in metabolism, its receptor signalling, as well as the exercise regulation of asprosin. Collectively, asprosin may have a vital regulatory effect on the improvement of metabolic disorders such as diabetes mellitus and obesity via exercise.

Asprosin modulates testicular functions during ageing in mice

Ageing is a gradual and multi-factorial process with a significant impact on fertility. The mechanism of declined testicular functions with age remains elusive. Asprosin is a novel fasting-induced gluconeogenic adipokine that regulates glucose homeostasis. However, the expression and potential role of asprosin in testicular functions with age are largely unexplored. So, the current study was aimed to examine the variation in asprosin expression in the mice testis and its correlation with OLFR734 receptor, insulin receptor (IR), GLUT-8 and various steroidogenic markers at different stages of postnatal development. The result demonstrated the highest expression of asprosin in reproductively active mice, which decreased significantly in aged mice testis. Asprosin expression declined simultaneously with declining testosterone production, testicular glucose and expression of OLFR734, IR, GLUT-8 and AR in aged mice testis. This suggests that declining asprosin expression with advancing age may be a causative factor for regressive changes in the testis. Further, the present study also evaluated the in vitro effect of asprosin on testicular functions of aged mice testis. The results showed that asprosin treatment improves testicular functions by stimulating the expression of OLFR734, StAR, 3β-HSD,17β-HSD, IR, GLUT-8, MCT-2&4, PCNA, Bcl2 proteins alongwith increased testosterone, insulin and lactate biosynthesis. Collectively, these findings indicate that a marked decline in asprosin and its receptor OLFR734 expression may result in decreased insulin sensitivity and glucose transport, leading to regressive changes in aged mice testis. Treatment of asprosin can possibly restore the testicular functions of aged mice by augmenting the testosterone, insulin and glucose levels.

Asprosin, a C-Terminal Cleavage Product of Fibrillin 1 Encoded by the FBN1 Gene, in Health and Disease

BACKGROUND

Asprosin is a novel fasting-induced, glucogenic, and orexigenic protein hormone that is discovered with the help of genetic studies in patients with neonatal progeroid syndrome. Asprosin is encoded by the penultimate 2 exons (65 and 66) of the fibrillin 1 (FBN1) gene. Profibrillin 1 is the unprocessed protein product of FBN1 and undergoes a proteolytic cleavage by furin enzyme to produce mature fibrillin 1 and asprosin. The main organ responsible for the asprosin production seems to be white adipose tissue.

SUMMARY

Asprosin promotes hepatic glucose release in the liver and appetite stimulation in the hypothalamus through activation of the cAMP signaling circuitry through interacting with its G protein-coupled receptor, called OR4M1. Increasing mass of evidence suggests that asprosin is involved in the development and progression of various clinical conditions including diabetes, obesity, cardiomyopathy, cancer, and polycystic ovarian syndrome. It regulates various cellular and physiological processes such as appetite stimulation, glucose release, insulin secretion, apoptotic cell death, and inflammatory response. In this review, we discuss the current literature on asprosin and try to shed light on the yet undiscovered functions of asprosin.

KEY MESSAGE

Asprosin is a key regulatory factor for preserving the homeostasis of energy metabolism.

5-HT recruits distinct neurocircuits to inhibit hunger-driven and non-hunger-driven feeding

Obesity is primarily a consequence of consuming calories beyond energetic requirements, but underpinning drivers have not been fully defined. 5-Hydroxytryptamine (5-HT) neurons in the dorsal Raphe nucleus (5-HTDRN) regulate different types of feeding behavior, such as eating to cope with hunger or for pleasure. Here, we observed that activation of 5-HTDRN to hypothalamic arcuate nucleus (5-HTDRN → ARH) projections inhibits food intake driven by hunger via actions at ARH 5-HT2C and 5-HT1B receptors, whereas activation of 5-HTDRN to ventral tegmental area (5-HTDRN → VTA) projections inhibits non-hunger-driven feeding via actions at 5-HT2C receptors. Further, hunger-driven feeding gradually activates ARH-projecting 5-HTDRN neurons via inhibiting their responsiveness to inhibitory GABAergic inputs; non-hunger-driven feeding activates VTA-projecting 5-HTDRN neurons through reducing a potassium outward current. Thus, our results support a model whereby parallel circuits modulate feeding behavior either in response to hunger or to hunger-independent cues.

Intracerebroventricular asprosin administration strongly stimulates hypothalamic-pituitary-testicular axis in rats

Asprosin, a protein-based secretary product of white adipose tissue, stimulates appetite hepatic glucose production. It crosses blood-brain barrier and stimulates appetite center and causes sperm chemotaxis but exact role of this endogenous agent is not completely known. This study was conducted to investigate possible effects of central asprosin infusion on the hormones involved in the hypothalamic-pituitary-testicular (HPT) axis and sperm cells. Spraque Dawley male rats were divided into four groups; control, sham, low asprosin (34) and high asprosin (68 nM) groups, (n = 10 for each group). Control group remain intact while a brain infusion kit was placed in the lateral ventricles of the rats in the sham group (artificial cerebrospinal fluid) and asprosin (34 and 68 nM) was infused for 14 days. At the end of the experiment, the hypothalamus, blood, and epididymis tissues of the rats were collected. Gonadotropin-releasing hormone (GnRH) mRNA and tissue protein levels were determined in the hypothalamus tissue by RT-PCR and Western Blot methods. Serum luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone levels were examined using the ELISA method from blood samples and sperm cells were examined in the epididymis tissue. GnRH mRNA and protein expressions of asprosin administered groups were higher than control and sham groups (p < 0.05). Asprosin infusion was also found to increase serum FSH, LH, and testosterone levels (p < 0.05). In addition, sperm density, motility, and progressive movement were observed to increase in asprosin administered groups (p < 0.05). This study suggests that central asprosin stimulate the HPT axis and also epididymis tissue. Our results implicates potential role for asprosin in male infertility.

Serum levels of Asprosin in patients diagnosed with coronary artery disease (CAD): a case-control study

Background

Coronary artery disease (CAD) is considered as a multi-faceted chronic inflammatory disease involving reduced blood supply to the myocardium as a result of accumulating lipids in the atrial walls. Visceral adiposity with disrupted release of adipokines play a key role in its pathogenesis. Asprosin is a newly identified fasting-induced glucogenic adipokine that has been related with metabolic disorders such as type II diabetes mellitus and polycystic ovary syndrome. The preset study sought to assess circulating asprosin in context of CAD.

Methods

In this study, serum levels of asprosin were determined in 88 CAD patients and 88 non-CAD healthy controls. Serum IL-6, TNF-α, asprosin and adiponectin were assessed using ELISA kits.

Results: Serum asprosin was found to be higher in CAD patients when compared to non-CAD subjects (7.84 ± 2.08 versus 5.02 ± 1.29 μg/mL, p <  0.001). Similarly, serum TNF-α, and IL-6 elevated in CAD group significantly (p <  0.001). However, circulating adiponectin diminished in CAD group when compared with non-CAD subjects (p < 0.001). Moreover, serum asprosin levels directly correlated with BMI, FBG, HOMA-IR, TG and TC. Logistic regression analyses showed that asprosin levels were associated with increased risk of developing CAD (odds ratio: 3.01, 95% CI: 2.16, 4.20 and p < 0.001), after adjusting for potential confounders (age, sex and BMI).

Conclusions

The present study findings suggested a possible relation of serum asprosin with the pathogenesis of CAD, in particular through insulin resistance and dyslipidemia.

Effect of sodium-glucose co-transporter-2 inhibitors on the levels of serum asprosin in patients with newly diagnosed type 2 diabetes mellitus

BACKGROUND

Asprosin, a novel adipokine that raises glucose levels and stimulates appetite, has been proved to be pathologically increased in populations predisposed to type 2 diabetes mellitus (T2DM), obesity, and cardiovascular diseases. The mechanisms of sodium-glucose co-transporter-2 (SGLT2) inhibitors for hypoglycemic effect and cardiovascular protection have not been fully clarified. Therefore, we conducted this study to assess change in the levels of serum asprosin after treatment with SGLT2 inhibitors in patients with newly diagnosed T2DM.

METHODS

This study was a randomized, double-blind, placebo-controlled trial. A total of 29 participants with newly diagnosed T2DM with body mass index (BMI) ≥ 23.0 kg/m² and haemoglobin A1c (HbA1c) levels of 58-85 mmol/mol (7.5-10%) were randomized to SGLT2 inhibitors dapagliflozin 10 mg/d (n = 19) or placebo (n = 10) treatment for 24 weeks. We analyzed asprosin concentrations by an enzyme-linked immunosorbent assay. Besides, body weight, BMI, HbA1c, fasting plasma glucose (FPG), and lipid levels were measured at baseline and 24 weeks.

RESULTS

At 24 weeks, participants with SGLT2 inhibitors treatment exhibited lower levels of serum asprosin (22.87 vs 45.06 ng/ml in the placebo group; P < 0.001) after adjusting for baseline values. The levels of body weight, BMI, HbA1c, FPG, and triglyceride (TG) were decreased, while high density lipoprotein-cholesterol (HDL-C) was increased after SGLT2 inhibitors dapagliflozin treatment compared with placebo (P < 0.05 for all). Low density lipoprotein-cholesterol (LDL-C) and total cholesterol (TC) levels were unchanged in the SGLT2 inhibitors group and placebo group. No statistical correlation was found between the levels of serum asprosin and body weight, BMI, HbA1c, FPG, and lipid levels during the SGLT2 inhibitor dapagliflozin treatment.

CONCLUSIONS

These findings indicated that SGLT2 inhibitors can lower serum asprosin levels and improve glucolipid and weight in patients with newly diagnosed T2DM, which may benefit the cardiovascular system. Trial registration CTR20131268; Registered 20 March 2014 CTR20150102; Registered 03 March 2015. http://www.chinadrugtrials.org.cn/clinicaltrials.searchlistdetail.dhtml .

Asprosin-A Fasting-Induced, Glucogenic, and Orexigenic Adipokine as a New Promising Player. Will It Be a New Factor in the Treatment of Obesity, Diabetes, or Infertility? A Review of the Literature

Asprosin is a recently discovered protein released during fasting conditions mainly by adipocytes from white adipose tissue. As a glucogenic peptide, it stimulates the release of glucose from hepatic cells by binding to the OLFR734 receptor and leading to the activation of the G protein-cAMP-PKA pathway. As it crosses the blood–brain barrier, it also acts as an orexigenic peptide that stimulates food intake through activation of AgRP neurons in the hypothalamus; thus, asprosin participates in maintaining the body’s energy homeostasis. Moreover, studies have shown that asprosin levels are pathologically elevated in obesity and related diseases. However, the administration of anti-asprosin antibodies can both normalize its concentration and reduce food intake in obese mice, which makes it an interesting factor to combat obesity and related diseases. Current research also draws attention to the relationship between asprosin and fertility, especially in men. Asprosin improves age- and obesity-related decrease in fertility potential by improving sperm motility. It should also be mentioned that plasma asprosin levels can be differentially modulated by physical activity; intense anaerobic exercise increases asprosin level, while aerobic exercise decreases it. However, further research is necessary to confirm the exact mechanisms of asprosin activity and its potential as a therapeutic target.