Autophagy Dysregulation and Obesity-Associated Pathologies

A methodology for gene level omics-WAS integration identifies genes influencing traits associated with cardiovascular risks: the Long Life Family Study

The Long Life Family Study (LLFS) enrolled 4953 participants in 539 pedigrees displaying exceptional longevity. To identify genetic mechanisms that affect cardiovascular risks in the LLFS population, we developed a multi-omics integration pipeline and applied it to 11 traits associated with cardiovascular risks. Using our pipeline, we aggregated gene-level statistics from rare-variant analysis, GWAS, and gene expression-trait association by Correlated Meta-Analysis (CMA). Across all traits, CMA identified 64 significant genes after Bonferroni correction (p ≤ 2.8 × 10-7), 29 of which replicated in the Framingham Heart Study (FHS) cohort. Notably, 20 of the 29 replicated genes do not have a previously known trait-associated variant in the GWAS Catalog within 50 kb. Thirteen modules in Protein-Protein Interaction (PPI) networks are significantly enriched in genes with low meta-analysis p-values for at least one trait, three of which are replicated in the FHS cohort. The functional annotation of genes in these modules showed a significant over-representation of trait-related biological processes including sterol transport, protein-lipid complex remodeling, and immune response regulation. Among major findings, our results suggest a role of triglyceride-associated and mast-cell functional genes FCER1A, MS4A2, GATA2, HDC, and HRH4 in atherosclerosis risks. Our findings also suggest that lower expression of ATG2A, a gene we found to be associated with BMI, may be both a cause and consequence of obesity. Finally, our results suggest that ENPP3 may play an intermediary role in triglyceride-induced inflammation. Our pipeline is freely available and implemented in the Nextflow workflow language, making it easily runnable on any compute platform ( https://nf-co.re/omicsgenetraitassociation ).

Mitochondrial Adaptation in Skeletal Muscle: Impact of Obesity, Caloric Restriction, and Dietary Compounds

PURPOSE OF REVIEW: The global obesity epidemic has become a major public health concern, necessitating comprehensive research into its adverse effects on various tissues within the human body. Among these tissues, skeletal muscle has gained attention due to its susceptibility to obesity-related alterations. Mitochondria are primary source of energy production in the skeletal muscle. Healthy skeletal muscle maintains constant mitochondrial content through continuous cycle of synthesis and degradation. However, obesity has been shown to disrupt this intricate balance. This review summarizes recent findings on the impact of obesity on skeletal muscle mitochondria structure and function. In addition, we summarize the molecular mechanism of mitochondrial quality control systems and how obesity impacts these systems. RECENT FINDINGS: Recent findings show various interventions aimed at mitigating mitochondrial dysfunction in obese model, encompassing strategies including caloric restriction and various dietary compounds. Obesity has deleterious effect on skeletal muscle mitochondria by disrupting mitochondrial biogenesis and dynamics. Caloric restriction, omega-3 fatty acids, resveratrol, and other dietary compounds enhance mitochondrial function and present promising therapeutic opportunities.

Overnutrition and Lipotoxicity: Impaired Efferocytosis and Chronic Inflammation as Precursors to Multifaceted Disease Pathogenesis

Overnutrition, driven by the consumption of high-fat, high-sugar diets, has reached epidemic proportions and poses a significant global health challenge. Prolonged overnutrition leads to the deposition of excessive lipids in adipose and non-adipose tissues, a condition known as lipotoxicity. The intricate interplay between overnutrition-induced lipotoxicity and the immune system plays a pivotal role in the pathogenesis of various diseases. This review aims to elucidate the consequences of impaired efferocytosis, caused by lipotoxicity-poisoned macrophages, leading to chronic inflammation and the subsequent development of severe infectious diseases, autoimmunity, and cancer, as well as chronic pulmonary and cardiovascular diseases. Chronic overnutrition promotes adipose tissue expansion which induces cellular stress and inflammatory responses, contributing to insulin resistance, dyslipidemia, and metabolic syndrome. Moreover, sustained exposure to lipotoxicity impairs the efferocytic capacity of macrophages, compromising their ability to efficiently engulf and remove dead cells. The unresolved chronic inflammation perpetuates a pro-inflammatory microenvironment, exacerbating tissue damage and promoting the development of various diseases. The interaction between overnutrition, lipotoxicity, and impaired efferocytosis highlights a critical pathway through which chronic inflammation emerges, facilitating the development of severe infectious diseases, autoimmunity, cancer, and chronic pulmonary and cardiovascular diseases. Understanding these intricate connections sheds light on potential therapeutic avenues to mitigate the detrimental effects of overnutrition and lipotoxicity on immune function and tissue homeostasis, thereby paving the way for novel interventions aimed at reducing the burden of these multifaceted diseases on global health.

Uncovering impaired mitochondrial and lysosomal function in adipose-derived stem cells from obese individuals with altered biological activity

BACKGROUND

Adipose-derived stem cells (ADSCs) have been extensively used in preclinical and clinical trials for treating various diseases. However, the differences between ADSCs from lean individuals (L-ADSCs) and those from obese individuals (O-ADSCs) have not been thoroughly investigated, particularly regarding their mitochondrial and lysosomal functions. Therefore, this study aims to evaluate the differences between L-ADSCs and O-ADSCs in terms of cell biological activity, mitochondria, and lysosomes.

METHODS

We first isolated and cultured L-ADSCs and O-ADSCs. We then compared the differences between the two groups in terms of biological activity, including cell proliferation, differentiation potential, and their effect on the polarization of macrophages. Additionally, we observed the mitochondrial and lysosomal morphology of ADSCs using an electronic microscope, MitoTracker Red, and lysotracker Red dyes. We assessed mitochondrial function by examining mitochondrial membrane potential and membrane fluidity, antioxidative ability, and cell energy metabolism. Lysosomal function was evaluated by measuring autophagy and phagocytosis. Finally, we performed transcriptome analysis of the ADSCs using RNA sequencing.

RESULTS

The biological activities of O-ADSCs were decreased, including cell immunophenotypic profiles, cell proliferation, and differentiation potential. Furthermore, compared to L-ADSCs, O-ADSCs promoted M1-type macrophage polarization and inhibited M2-type macrophage polarization. Additionally, the mitochondrial morphology of O-ADSCs was altered, with the size of the cells becoming smaller and mitochondrial fragments increasing. O-ADSCs also exhibited decreased mitochondrial membrane potential and membrane fluidity, antioxidative ability, and energy metabolism. With respect to lysosomes, O-ADSCs contained ungraded materials in their lysosomes, enhanced lysosomal permeability, and reduced autophagy and phagocytosis ability. RNA sequence analysis indicated that the signalling pathways related to cell senescence, cancer, and inflammation were upregulated, whereas the signalling pathways associated with stemness, cell differentiation, metabolism, and response to stress and stimuli were downregulated.

CONCLUSIONS

This study indicates that ADSCs from individuals (BMI > 30 kg/m2) exhibit impaired mitochondrial and lysosomal function with decreased biological activity.

Cellular Recycling Gone Wrong: The Role of Dysregulated Autophagy and Hyperactive mTORC1 in the Pathogenesis of Sarcoidosis

BACKGROUND AND AIMS

Autophagy is a highly regulated, complex intracellular recycling process that is vital to maintaining cellular homeostasis in response to diverse conditions and stressors. Despite the presence of robust regulatory pathways, the intricate and multi-step nature of autophagy creates opportunity for dysregulation. Errors in autophagy have been implicated in the development of a broad range of clinical pathologies including granulomatous disease. Specifically, activation of the mTORC1 pathway has been identified as a key negative regulator of autophagic flux, prompting the study of dysregulated mTORC1 signaling in the pathogenesis of sarcoidosis. Our review: We conducted a thorough search of the extant literature to identify the regulatory pathways of autophagy, and more specifically the implication of upregulated mTORC1 pathways in the pathogenesis of sarcoidosis. We review data showing spontaneous granuloma formation in animal models with upregulate mTORC1 signaling, human genetic studies showing mutation in autophagy genes in sarcoidosis patients, and clinical data showing that targeting autophagy regulatory molecules like mTORC1 may provide new therapeutic approaches for sarcoidosis.

CONCLUSIONS

Given the incomplete understanding of sarcoidosis pathogenesis and the toxicities of current treatments, a more complete understanding of sarcoidosis pathogenesis is crucial for the development of more effective and safer therapies. In this review, we propose a strong molecular pathway driving sarcoidosis pathogenesis at which autophagy is at the center. A more complete understanding of autophagy and its regulatory molecules, like mTORC1, may provide a window into new therapeutic approaches for sarcoidosis.

The role of Elateriospermum tapos yoghurt in mitigating high-fat dietary cause of maternal obesity-an experimental study

Maternal obesity is the key predictor for childhood obesity and neurodevelopmental delay in the offspring. Medicinal plants are considered to be the safe and best option, and at the same time, probiotic consumption during pregnancy provides beneficial effects for both the mother and the child. Current research has shown that Elateriospermum tapos (E. tapos) yoghurt is safe to consume and consists of many bioactive compounds that can exert an anti-obesity effect. Thus, this study has been designed to study the role of E. tapos yoghurt in mitigating maternal obesity. In this study, a total of 48 female Sprague Dawley (SD) rats were assigned to six groups, with eight rats per group, and obesity was induced over 16 weeks with a high-fat diet (HFD) pellet. On the 17th week, the rats were allowed to mate and pregnancy was confirmed through vaginal smear. The obese induced group was further divided into negative and positive control groups, followed by E. tapos yoghurt treatment groups with three different concentrations (5, 50, and 500 mg/kg). The changes in body weight, calorie intake, lipid profile, liver profile, renal profile, and histopathological analysis were measured on postnatal day (PND) 21. The results show that the group with the highest concentration of E. tapos yoghurt (HYT500) supplementation shows gradual reduction in body weight and calorie intake on PND 21 and modulates the lipid level, liver, and renal enzymes to a normal level similar to the normal group. In histological analysis, HYT500 reverses the damage caused by HFD in liver and colon, and reverses the adipocytes' hypertrophy in retroperitoneal white adipose tissue and visceral fat. In conclusion, supplementation of E. tapos yoghurt during the gestational period up to weaning is effective in the gradual weight loss of maternal obese dams from the 500-mg/kg-supplemented group in this study.

Obesity, non-alcoholic fatty liver disease and hepatocellular carcinoma: current status and therapeutic targets

Obesity is a global epidemic and overwhelming evidence indicates that it is a risk factor for numerous cancers, including hepatocellular carcinoma (HCC), the third leading cause of cancer-related deaths worldwide. Obesity-associated hepatic tumorigenesis develops from nonalcoholic fatty liver disease (NAFLD), progressing to nonalcoholic steatohepatitis (NASH), cirrhosis and ultimately to HCC. The rising incidence of obesity is resulting in an increased prevalence of NAFLD and NASH, and subsequently HCC. Obesity represents an increasingly important underlying etiology of HCC, in particular as the other leading causes of HCC such as hepatitis infection, are declining due to effective treatments and vaccines. In this review, we provide a comprehensive overview of the molecular mechanisms and cellular signaling pathways involved in the pathogenesis of obesity-associated HCC. We summarize the preclinical experimental animal models available to study the features of NAFLD/NASH/HCC, and the non-invasive methods to diagnose NAFLD, NASH and early-stage HCC. Finally, since HCC is an aggressive tumor with a 5-year survival of less than 20%, we will also discuss novel therapeutic targets for obesity-associated HCC and ongoing clinical trials.

Inhibition of autophagy with chloroquine dysregulates mitochondrial quality control and energetics in adipocytes

Autophagy is a complex degradation pathway through which damaged or dysfunctional proteins and organelles are removed. Its pharmacological modulators have been extensively used in a wide range of basic research and preclinical studies. However, the effects of these inhibitors on metabolism, in addition to autophagy inhibition, are not fully elucidated. Chloroquine is a clinically relevant compound that inhibits autophagy by preventing the fusion of autophagosomes with lysosomes. In this study, we aimed to examine the effect of chloroquine on mitochondrial quality control and respiratory function by utilizing 3T3-L1 mouse adipocytes treated with chloroquine at various time points. We found that chloroquine could disturb genes related to mitochondrial fission, biogenesis, and mitophagy, leading to mitochondrial DNA damage. Although the inhibition of autophagy by chloroquine resulted in an increased prohibitin expression, respiratory function was downregulated in a time-dependent manner. Moreover, chloroquine treatment induced oxidative stress, apoptosis, and metabolic dysregulation. These data demonstrated that chloroquine significantly affected mitochondrial respiratory function and metabolism, which was consistent with impaired mitochondrial quality associated with autophagy inhibition.

Interaction between autophagy and the NLRP3 inflammasome in Alzheimer’s and Parkinson’s disease

Autophagy degrades phagocytosed damaged organelles, misfolded proteins, and various pathogens through lysosomes as an essential way to maintain cellular homeostasis. Autophagy is a tightly regulated cellular self-degradation process that plays a crucial role in maintaining normal cellular function and homeostasis in the body. The NLRP3 inflammasome in neuroinflammation is a vital recognition receptor in innate cellular immunity, sensing external invading pathogens and endogenous stimuli and further triggering inflammatory responses. The NLRP3 inflammasome forms an inflammatory complex by recognizing DAMPS or PAMPS, and its activation triggers caspase-1-mediated cleavage of pro-IL-1β and pro-IL-18 to promote the inflammatory response. In recent years, it has been reported that there is a complex interaction between autophagy and neuroinflammation. Strengthening autophagy can regulate the expression of NLRP3 inflammasome to reduce neuroinflammation in neurodegenerative disease and protect neurons. However, the related mechanism is not entirely clear. The formation of protein aggregates is one of the standard features of Neurodegenerative diseases. A large number of toxic protein aggregates can induce inflammation. In theory, activation of the autophagy pathway can remove the potential toxicity of protein aggregates and delay the progression of the disease. This article aims to review recent research on the interaction of autophagy, NLRP3 inflammasome, and protein aggregates in Alzheimer’s disease (AD) and Parkinson’s disease (PD), analyze the mechanism and provide theoretical references for further research in the future.

Autophagy modulation in resveratrol protective effects on steroidogenesis in high-fat diet-fed mice and H2O2-challenged TM3 cells

BACKGROUND

Autophagy dysregulation and oxidative stress play critical pathophysiological roles in developing obesity-related metabolic health disorders. This study aims to investigate how autophagy modulation is related to resveratrol (RSV) antioxidant activities and preventive effects on steroidogenesis decline associated with a high-fat diet (HFD) and oxidative damage.

METHODS AND RESULTS

Eight-week-old C57BL/6 J male mice were fed with HFD with or without supplement RSV (400 mg/kg/day) by gavage for 16 weeks. The control group was fed with a standard diet with no RSV or the same amount of RSV. Mouse Leydig cell line TM3 cell was used for in vitro studies. Oxidative stress was induced in TM3 cells with H₂O₂, followed by RSV treatment plus autophagy activator rapamycin or autophagy inhibitor 3-methyladenine, respectively. RSV supplement could upregulate proteins level of StAR and mitochondrial proteins COX4 and mtTFA, indicating the amelioration of steroidogenesis decline and mitochondrial dysfunction caused by HFD. Antioxidants such as GPx4 and SOD2 were improved by RSV as well. The observation of autophagosomes and the changes in expressions of LC3II/I, Beclin1, and Atg7 indicated that RSV could reverse the autophagy defect associated with HFD. 3-methyladenine inhibition of autophagy partially abolished RSV protection on mitochondrial function and steroidogenesis in H₂O₂-challenged TM3 cells. However, the combination use of rapamycin and RSV did not improve protection on Leydig cells against oxidative damage.

CONCLUSIONS

The stimulation of autophagy by RSV is closely linked to its antioxidant actions and positive impact on steroidogenesis in HFD mice. The findings suggest RSV is protective against obesity-related Leydig cell impairment.

Multiple Mechanisms Converging on Transcription Factor EB Activation by the Natural Phenol Pterostilbene

Pterostilbene (Pt) is a potentially beneficial plant phenol. In contrast to many other natural compounds (including the more celebrated resveratrol), Pt concentrations producing significant effects in vitro can also be reached with relative ease in vivo. Here we focus on some of the mechanisms underlying its activity, those involved in the activation of transcription factor EB (TFEB). A set of processes leading to this outcome starts with the generation of ROS, attributed to the interaction of Pt with complex I of the mitochondrial respiratory chain, and spreads to involve Ca²⁺ mobilization from the ER/mitochondria pool, activation of CREB and AMPK, and inhibition of mTORC1. TFEB migration to the nucleus results in the upregulation of autophagy and lysosomal and mitochondrial biogenesis. Cells exposed to several μM levels of Pt experience a mitochondrial crisis, an indication for using low doses in therapeutic or nutraceutical applications. Pt afforded significant functional improvements in a zebrafish embryo model of ColVI-related myopathy, a pathology which also involves defective autophagy. Furthermore, long-term supplementation with Pt reduced body weight gain and increased transcription levels of Ppargc1a and Tfeb in a mouse model of diet-induced obesity. These in vivo findings strengthen the in vitro observations and highlight the therapeutic potential of this natural compound.

Roles of IκB kinases and TANK-binding kinase 1 in hepatic lipid metabolism and nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease and is strongly associated with obesity-related ectopic fat accumulation in the liver. Hepatic lipid accumulation encompasses a histological spectrum ranging from simple steatosis to nonalcoholic steatohepatitis (NASH), which can progress to cirrhosis and hepatocellular carcinoma. Given that dysregulated hepatic lipid metabolism may be an onset factor in NAFLD, understanding how hepatic lipid metabolism is modulated in healthy subjects and which steps are dysregulated in NAFLD subjects is crucial to identify effective therapeutic targets. Additionally, hepatic inflammation is involved in chronic hepatocyte damage during NAFLD progression. As a key immune signaling hub that mediates NF-κB activation, the IκB kinase (IKK) complex, including IKKα, IKKβ, and IKKγ (NEMO), has been studied as a crucial regulator of the hepatic inflammatory response and hepatocyte survival. Notably, TANK-binding kinase 1 (TBK1), an IKK-related kinase, has recently been revealed as a potential link between hepatic inflammation and energy metabolism. Here, we review (1) the biochemical steps of hepatic lipid metabolism; (2) dysregulated lipid metabolism in obesity and NAFLD; and (3) the roles of IKKs and TBK1 in obesity and NAFLD.

Increased Expression of Fibroblast Activation Protein is Associated with Autophagy Dysregulation and Oxidative Stress in Obese Women with Uterine Fibroids

Uterine fibroids (UF) represent an immense health burden throughout the world. Obesity is considered one of the risk factors for UF development; however, the underlying mechanisms remain largely unexplored. We investigated the effect of obesity on fibroblast activation and its association with inflammation, autophagy dysfunction, and oxidative stress in UF patients. Thirty-five pre-menopausal UF patients were included in this study and classified into non-obese group (BM1 ≤ 30 kg/m², n = 15) and obese group (BMI > 30 kg/m², n = 20). Tissue samples were collected from fibroids and adjacent normal myometrium. Our results showed increased expression of fibroblast activation protein (FAP) together with markers of autophagy, inflammation, and oxidative stress in UF patients, which were all more markedly upregulated in obese compared to non-obese patients. In addition, BMI was significantly positive correlated with FAP and autophagy markers. In conclusion, the results of the present study suggest that obesity-associated autophagy dysregulation together with increased FAP expression may increase the risk of UFs in obese women.

COVID-19 and obesity: fighting two pandemics with intermittent fasting

Obesity is strongly and independently associated with an increased risk of severe illness and death from coronavirus disease 2019 (COVID-19). The pathophysiological changes that result from elevated body weight lead to metabolic dysfunction, chronic inflammation, impaired immunological responses, and multisystem disorders, which increase vulnerability to severe illness from COVID-19. While vaccination strategies are under way across the world, the second and third waves of the pandemic, along with the emergence of novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strains, continue to threaten the stability of medical systems worldwide. Furthermore, evidence from previous pandemics suggests that vaccines are less effective in obese individuals than in their healthy-weight counterparts over the long term. Therefore, a consideration of lifestyle changes that can boost metabolic health and immunity is critical to reduce the risk of complications and severe illness from viral infection. In this review, we discuss the potential mechanisms linking excess body weight with COVID-19 morbidity. We also present evidence that intermittent fasting (IF), a dietary program that has gained popularity in recent years, may be an effective strategy to improve metabolic health and immunity and thus reduce the impact of obesity on COVID-19 morbidity and mortality.

Obesity cardiomyopathy: evidence, mechanisms, and therapeutic implications

The prevalence of heart failure is on the rise and imposes a major health threat, in part, due to the rapidly increased prevalence of overweight and obesity. To this point, epidemiological, clinical, and experimental evidence supports the existence of a unique disease entity termed “obesity cardiomyopathy,” which develops independent of hypertension, coronary heart disease, and other heart diseases. Our contemporary review evaluates the evidence for this pathological condition, examines putative responsible mechanisms, and discusses therapeutic options for this disorder. Clinical findings have consolidated the presence of left ventricular dysfunction in obesity. Experimental investigations have uncovered pathophysiological changes in myocardial structure and function in genetically predisposed and diet-induced obesity. Indeed, contemporary evidence consolidates a wide array of cellular and molecular mechanisms underlying the etiology of obesity cardiomyopathy including adipose tissue dysfunction, systemic inflammation, metabolic disturbances (insulin resistance, abnormal glucose transport, spillover of free fatty acids, lipotoxicity, and amino acid derangement), altered intracellular especially mitochondrial Ca²⁺ homeostasis, oxidative stress, autophagy/mitophagy defect, myocardial fibrosis, dampened coronary flow reserve, coronary microvascular disease (microangiopathy), and endothelial impairment. Given the important role of obesity in the increased risk of heart failure, especially that with preserved systolic function and the recent rises in COVID-19-associated cardiovascular mortality, this review should provide compelling evidence for the presence of obesity cardiomyopathy, independent of various comorbid conditions, underlying mechanisms, and offer new insights into potential therapeutic approaches (pharmacological and lifestyle modification) for the clinical management of obesity cardiomyopathy.

Placental Antioxidant Defenses and Autophagy-Related Genes in Maternal Obesity and Gestational Diabetes Mellitus

Maternal obesity and gestational diabetes mellitus (GDM) are increasing worldwide, representing risk factors for both mother and child short/long-term outcomes. Oxidative stress, lipotoxicity and altered autophagy have already been reported in obesity, but few studies have focused on obese pregnant women with GDM. Antioxidant and macro/chaperone-mediated autophagy (CMA)-related gene expressions were evaluated herein in obese and GDM placentas. A total of 47 women with singleton pregnancies delivered by elective cesarean section were enrolled: 16 normal weight (NW), 18 obese with no comorbidities (OB GDM(–)), 13 obese with GDM (OB GDM(+)). Placental gene expression was assessed by real-time PCR. Antioxidant gene expression (CAT, GPX1, GSS) decreased, the pro-autophagic ULK1 gene increased and the chaperone-mediated autophagy regulator PHLPP1 decreased in OB GDM(–) vs. NW. On the other hand, PHLPP1 expression increased in OB GDM(+) vs. OB GDM(–). When analyzing results in relation to fetal sex, we found sexual dimorphism for both antioxidant and CMA-related gene expressions. These preliminary results can pave the way for further analyses aimed at elucidating the placental autophagy role in metabolic pregnancy disorders and its potential targetability for the treatment of diabetes outcomes.

Autophagy-mediated metabolic effects of aspirin

Salicylate, the active derivative of aspirin (acetylsalicylate), recapitulates the mode of action of caloric restriction inasmuch as it stimulates autophagy through the inhibition of the acetyltransferase activity of EP300. Here, we directly compared the metabolic effects of aspirin medication with those elicited by 48 h fasting in mice, revealing convergent alterations in the plasma and the heart metabolome. Aspirin caused a transient reduction of general protein acetylation in blood leukocytes, accompanied by the induction of autophagy. However, these effects on global protein acetylation could not be attributed to the mere inhibition of EP300, as determined by epistatic experiments and exploration of the acetyl-proteome from salicylate-treated EP300-deficient cells. Aspirin reduced high-fat diet-induced obesity, diabetes, and hepatosteatosis. These aspirin effects were observed in autophagy-competent mice but not in two different models of genetic (Atg4b^−/− or Bcln1^+/−) autophagy-deficiency. Aspirin also improved tumor control by immunogenic chemotherapeutics, and this effect was lost in T cell-deficient mice, as well as upon knockdown of an essential autophagy gene (Atg5) in cancer cells. Hence, the health-improving effects of aspirin depend on autophagy.

High-fat diet-induced and genetically inherited obesity differentially alters DNA methylation profile in the germline of adult male rats

BACKGROUND

Paternal obesity has been associated with reduced live birth rates. It could lead to inheritance of metabolic disturbances to the offspring through epigenetic mechanisms. However, obesity is a multifactorial disorder with genetic or environmental causes. Earlier we had demonstrated differential effects of high-fat diet-induced obesity (DIO) and genetically inherited obesity (GIO) on metabolic, hormonal profile, male fertility, and spermatogenesis using two rat models. The present study aimed to understand the effect of DIO and GIO on DNA methylation in male germline, and its subsequent effects on the resorbed (post-implantation embryo loss) and normal embryos. First, we assessed the DNA methylation enzymatic machinery in the testis by Real-Time PCR, followed global DNA methylation levels in spermatozoa and testicular cells by ELISA and flow cytometry, respectively. Further, we performed Methylation Sequencing in spermatozoa for both the groups. Sequencing data in spermatozoa from both the groups were validated using Pyrosequencing. Expression of the differentially methylated genes was assessed in the resorbed and normal embryos sired by the DIO group using Real-Time PCR for functional validation.

RESULTS

We noted a significant decrease in Dnmt transcript and global DNA methylation levels in the DIO group and an increase in the GIO group. Sequencing analysis showed 16,966 and 9113 differentially methylated regions in the spermatozoa of the DIO and GIO groups, respectively. Upon pathway analysis, we observed genes enriched in pathways involved in embryo growth and development namely Wnt, Hedgehog, TGF-beta, and Notch in spermatozoa for both the groups, the methylation status of which partially correlated with the gene expression pattern in resorbed and normal embryos sired by the DIO group.

CONCLUSION

Our study reports the mechanism by which diet-induced and genetically inherited obesity causes differential effects on the DNA methylation in the male germline that could be due to a difference in the white adipose tissue accumulation. These differences could either lead to embryo loss or transmit obesity-related traits to the offspring in adult life.

Neutrophil Extracellular Traps (NETs) and Damage-Associated Molecular Patterns (DAMPs): Two Potential Targets for COVID-19 Treatment

COVID-19 is a pandemic disease caused by the new coronavirus SARS-CoV-2 that mostly affects the respiratory system. The consequent inflammation is not able to clear viruses. The persistent excessive inflammatory response can build up a clinical picture that is very difficult to manage and potentially fatal. Modulating the immune response plays a key role in fighting the disease. One of the main defence systems is the activation of neutrophils that release neutrophil extracellular traps (NETs) under the stimulus of autophagy. Various molecules can induce NETosis and autophagy; some potent activators are damage-associated molecular patterns (DAMPs) and, in particular, the high-mobility group box 1 (HMGB1). This molecule is released by damaged lung cells and can induce a robust innate immunity response. The increase in HMGB1 and NETosis could lead to sustained inflammation due to SARS-CoV-2 infection. Therefore, blocking these molecules might be useful in COVID-19 treatment and should be further studied in the context of targeted therapy.

Autophagy in metabolic syndrome: breaking the wheel by targeting the renin-angiotensin system

Metabolic syndrome (MetS) is a complex, emerging epidemic which disrupts the metabolic homeostasis of several organs, including liver, heart, pancreas, and adipose tissue. While studies have been conducted in these research areas, the pathogenesis and mechanisms of MetS remain debatable. Lines of evidence show that physiological systems, such as the renin-angiotensin system (RAS) and autophagy play vital regulatory roles in MetS. RAS is a pivotal system known for controlling blood pressure and fluid balance, whereas autophagy is involved in the degradation and recycling of cellular components, including proteins. Although RAS is activated in MetS, the interrelationship between RAS and autophagy varies in glucose homeostatic organs and their cross talk is poorly understood. Interestingly, autophagy is attenuated in the liver during MetS, whereas autophagic activity is induced in adipose tissue during MetS, indicating tissue-specific discordant roles. We discuss in vivo and in vitro studies conducted in metabolic tissues and dissect their tissue-specific effects. Moreover, our review will focus on the molecular mechanisms by which autophagy orchestrates MetS and the ways future treatments could target RAS in order to achieve metabolic homeostasis.

Global profiling of O-GlcNAcylated and/or phosphorylated proteins in hepatoblastoma

O-linked-β-N-acetylglucosamine (O-GlcNAc) glycosylation (O-GlcNAcylation) and phosphorylation are critical posttranslational modifications that are involved in regulating the functions of proteins involved in tumorigenesis and the development of various solid tumors. However, a detailed characterization of the patterns of these modifications at the peptide or protein level in hepatoblastoma (HB), a highly malignant primary hepatic tumor with an extremely low incidence in children, has not been performed. Here, we examined O-GlcNAc-modified or phospho-modified peptides and proteins in HB through quantitative proteomic analysis of HB tissues and paired normal liver tissues. Our results identified 114 O-GlcNAcylated peptides belonging to 78 proteins and 3494 phosphorylated peptides in 2088 proteins. Interestingly, 41 proteins were modified by both O-GlcNAcylation and phosphorylation. These proteins are involved in multiple molecular and cellular processes, including chromatin remodeling, transcription, translation, transportation, and organelle organization. In addition, we verified the accuracy of the proteomics results and found a competitive inhibitory effect between O-GlcNAcylation and phosphorylation of HSPB1. Further, O-GlcNAcylation modification of HSPB1 promoted proliferation and enhanced the chemotherapeutic resistance of HB cell lines in vitro. Collectively, our research suggests that O-GlcNAc-modified and/or phospho-modified proteins may play a crucial role in the pathogenesis of HB.

Hepatic stress associated with pathologies characterized by disturbed glucose production

The liver is an organ with many facets, including a role in energy production and metabolic balance, detoxification and extraordinary capacity of regeneration. Hepatic glucose production plays a crucial role in the maintenance of normal glucose levels in the organism i.e. between 0.7 to 1.1 g/l. The loss of this function leads to a rare genetic metabolic disease named glycogen storage disease type I (GSDI), characterized by severe hypoglycemia during short fasts. On the contrary, type 2 diabetes is characterized by chronic hyperglycemia, partly due to an overproduction of glucose by the liver. Indeed, diabetes is characterized by increased uptake/production of glucose by hepatocytes, leading to the activation of de novo lipogenesis and the development of a non-alcoholic fatty liver disease. In GSDI, the accumulation of glucose-6 phosphate, which cannot be hydrolyzed into glucose, leads to an increase of glycogen stores and the development of hepatic steatosis. Thus, in these pathologies, hepatocytes are subjected to cellular stress mainly induced by glucotoxicity and lipotoxicity. In this review, we have compared hepatic cellular stress induced in type 2 diabetes and GSDI, especially oxidative stress, autophagy deregulation, and ER-stress. In addition, both GSDI and diabetic patients are prone to the development of hepatocellular adenomas (HCA) that occur on a fatty liver in the absence of cirrhosis. These HCA can further acquire malignant traits and transform into hepatocellular carcinoma. This process of tumorigenesis highlights the importance of an optimal metabolic control in both GSDI and diabetic patients in order to prevent, or at least to restrain, tumorigenic activity during disturbed glucose metabolism pathologies.

Autophagy in Metabolic Age-Related Human Diseases

Autophagy is a highly conserved homeostatic cellular mechanism that mediates the degradation of damaged organelles, protein aggregates, and invading pathogens through a lysosome-dependent pathway. Over the last few years, specific functions of autophagy have been discovered in many tissues and organs; however, abnormal upregulation or downregulation of autophagy has been depicted as an attribute of a variety of pathologic conditions. In this review, we will describe the current knowledge on the role of autophagy, from its regulation to its physiological influence, in metabolic age-related disorders. Finally, we propose to discuss the therapeutic potential of pharmacological and nutritional modulators of autophagy to treat metabolic diseases.