Prophylactic and therapeutic vaccines for obesity

Anticipatory in silico vaccine designing based on specific antigenic epitopes from Streptococcus mutans against diabetic pathogenesis

The metabolic disorder Type 2 Diabetes Mellitus (T2DM) is characterized by hyperglycaemia, causing increased mortality and healthcare burden globally. Recent studies emphasize the impact of metabolites in the gut microbiome on T2DM pathogenesis. One such microbial metabolite, imidazole propionate (Imp) derived from histidine metabolism, is shown to interfere with insulin signalling and other key metabolic processes. The key enzyme urocanate reductase (UrdA) is involved in ImP production. Hence, we propose to develop a novel therapeutic vaccine against the gut microbe producing Imp based on UrdA as a target for treating T2DM using immunoinformatics approach. Antigenic, non-allergic, non-toxic, and immunogenic B cell and T cell potential epitopes were predicted using immunoinformatics servers and tools. These epitopes were adjoined using linker sequences, and to increase immunogenicity, adjuvants were added at the N-terminal end of the final vaccine construct. Further, to confirm the vaccine's safety, antigenic and non-allergic characteristics of the developed vaccine construct were assessed. The tertiary structure of the UrdA vaccine sequence was predicted using molecular modelling tools. A molecular docking study was utilized to understand the vaccine construct interaction with immune receptors, followed by molecular dynamics simulation and binding free energy calculations to assess stability of the complex. In silico cloning techniques were employed to evaluate the expression and translation effectiveness of the developed vaccine in pET vector. In conclusion, this study developed an in silico epitope-based vaccine construct as a novel adjunct therapeutic for T2DM.

Graphical Abstract

E4orf1: The triple agent of adenovirus - Unraveling its roles in oncogenesis, infectious obesity and immune responses in virus replication and vector therapy

Human Adenoviruses (HAdV) are nearly ubiquitous pathogens comprising numerous sub-types that infect various tissues and organs. Among many encoded proteins that facilitate viral replication and subversion of host cellular processes, the viral E4orf1 protein has emerged as an intriguing yet under-investigated player in the complex interplay between the virus and its host. E4orf1 has gained attention as a metabolism activator and oncogenic agent, while recent research is showing that E4orf1 may play a more important role in modulating cellular pathways such as PI3K-Akt-mTOR, Ras, the immune response and further HAdV replication stages than previously anticipated. In this review, we aim to explore the structure, molecular mechanisms, and biological functions of E4orf1, shedding light on its potentially multifaceted roles during HAdV infection, including metabolic diseases and oncogenesis. Furthermore, we discuss the role of functional E4orf1 in biotechnological applications such as Adenovirus (AdV) vaccine vectors and oncolytic AdV. By dissecting the intricate relationships between HAdV types and E4orf1 proteins, this review provides valuable insights into viral pathogenesis and points to promising areas of future research.

Adenovirus 36 Coinfection in People Living with HIV and its Impact on Lipohypertrophy

BACKGROUND

Previous studies have implicated human adenovirus 36 (Adv36) as a potential contributor to overweight and obesity. People living with HIV have an altered body composition compared to healthy individuals. There is still no evidence to confirm the relationship of Adv36 as one of the causes of lipohypertrophy. The main objective of this study was to verify the viral Adv36 infection as a factor associated with the presence of lipohypertrophy in HIV-infected individuals.

METHODS

A case-control study on people with HIV treated at a specialized public health service in southern Brazil. Subjects underwent interviews, diagnostic tests, and anthropometry to determine lipodystrophy and its classification. Demographic and clinical data were examined to investigate the presence of Adv36. The cases were participants with lipohypertrophy, and the controls were eutrophic participants.

RESULTS

101 participants were included (38 cases and 63 controls), and the frequency of Adv36 infection was 10.9%. There was a statistically significant association between lipohypertrophy and the female sex (p < 0.001), and a trend for the presence of Adv36 (p = 0.059) and lipohypertrophy. After adjustment for confounders, Adv36 has not considered an independent risk factor for lipohypertrophy. Lower levels of glucose were associated with Adv36 infection.

CONCLUSION

There was a significant association between lipohypertrophy and the female sex, and no association with lipohypertrophy and Adv36, perhaps due to the small sample size.

Anti-Obesity Medications and Investigational Agents: An Obesity Medicine Association (OMA) Clinical Practice Statement (CPS) 2022

Background

This "Anti-Obesity Medications and Investigational Agents: An Obesity Medicine Association Clinical Practice Statement 2022" is intended to provide clinicians an overview of Food and Drug Administration (FDA) approved anti-obesity medications and investigational anti-obesity agents in development.

Methods

The scientific information for this Clinical Practice Statement (CPS) is based upon published scientific citations, clinical perspectives of OMA authors, and peer review by the Obesity Medicine Association leadership.

Results

This CPS describes pharmacokinetic principles applicable to those with obesity, and discusses the efficacy and safety of anti-obesity medications [e.g., phentermine, semaglutide, liraglutide, phentermine/topiramate, naltrexone/bupropion, and orlistat, as well as non-systemic superabsorbent oral hydrogel particles (which is technically classified as a medical device)]. Other medications discussed include setmelanotide, metreleptin, and lisdexamfetamine dimesylate. Data regarding the use of combination anti-obesity pharmacotherapy, as well as use of anti-obesity pharmacotherapy after bariatric surgery are limited; however, published data support such approaches. Finally, this CPS discusses investigational anti-obesity medications, with an emphasis on the mechanisms of action and summary of available clinical trial data regarding tirzepatide.

Conclusion

This "Anti-Obesity Medications and Investigational Agents: An Obesity Medicine Association Clinical Practice Statement 2022" is one of a series of OMA CPSs designed to assist clinicians in the care of patients with pre-obesity/obesity.

Multifactorial Basis and Therapeutic Strategies in Metabolism-Related Diseases

Throughout the 20th and 21st centuries, the incidence of non-communicable diseases (NCDs), also known as chronic diseases, has been increasing worldwide. Changes in dietary and physical activity patterns, along with genetic conditions, are the main factors that modulate the metabolism of individuals, leading to the development of NCDs. Obesity, diabetes, metabolic associated fatty liver disease (MAFLD), and cardiovascular diseases (CVDs) are classified in this group of chronic diseases. Therefore, understanding the underlying molecular mechanisms of these diseases leads us to develop more accurate and effective treatments to reduce or mitigate their prevalence in the population. Given the global relevance of NCDs and ongoing research progress, this article reviews the current understanding about NCDs and their related risk factors, with a focus on obesity, diabetes, MAFLD, and CVDs, summarizing the knowledge about their pathophysiology and highlighting the currently available and emerging therapeutic strategies, especially pharmacological interventions. All of these diseases play an important role in the contamination by the SARS-CoV-2 virus, as well as in the progression and severity of the symptoms of the coronavirus disease 2019 (COVID-19). Therefore, we briefly explore the relationship between NCDs and COVID-19.

Findings from Studies Are Congruent with Obesity Having a Viral Origin, but What about Obesity-Related NAFLD?

Infection has recently started receiving greater attention as an unusual causative/inducing factor of obesity. Indeed, the biological plausibility of infectobesity includes direct roles of some viruses to reprogram host metabolism toward a more lipogenic and adipogenic status. Furthermore, the probability that humans may exchange microbiota components (virome/virobiota) points out that the altered response of IFN and other cytokines, which surfaces as a central mechanism for adipogenesis and obesity-associated immune suppression, is due to the fact that gut microbiota uphold intrinsic IFN signaling. Last but not least, the adaptation of both host immune and metabolic system under persistent viral infections play a central role in these phenomena. We hereby discuss the possible link between adenovirus and obesity-related nonalcoholic fatty liver disease (NAFLD). The mechanisms of adenovirus-36 (Ad-36) involvement in hepatic steatosis/NAFLD consist in reducing leptin gene expression and insulin sensitivity, augmenting glucose uptake, activating the lipogenic and pro-inflammatory pathways in adipose tissue, and increasing the level of macrophage chemoattractant protein-1, all of these ultimately leading to chronic inflammation and altered lipid metabolism. Moreover, by reducing leptin expression and secretion Ad-36 may have in turn an obesogenic effect through increased food intake or decreased energy expenditure via altered fat metabolism. Finally, Ad-36 is involved in upregulation of cAMP, phosphatidylinositol 3-kinase, and p38 signaling pathways, downregulation of Wnt10b expression, increased expression of CCAAT/enhancer binding protein-beta, and peroxisome proliferator-activated receptor gamma 2 with consequential lipid accumulation.

Adenovirus-36 infection and obesity: A case control study of Turkish women with polycystic ovary syndrome

BACKGROUND AND AIMS

Adenovirus-36 (Ad-36) seropositivity has been shown to be involved in the aetiology of obesity. The aim of this study was to examine Ad-36 positivity in obese and normal-weight patients with polycystic ovary syndrome (PCOS).

METHODS

There were two groups including 92 and 110 subjects. This study was a prospective case-control study. The enzyme-immunoassay method was used to quantitatively determine antibodies (Abs) specific to human Ad-36 in the serum samples. Age, body mass index (BMI), fasting glucose levels and insulin levels of the participants were recorded. The PCOS and control group patients were divided into two groups: the overweight group with BMI ≥25 kg/m² and non-obese group with BMI <25 kg/m².

RESULTS

Ad-36 Ab positivity in the PCOS group was found to be significantly higher than that in the control group (p < 0.001). Ad-36 Ab positivity was significantly higher in the PCOS obese group than in the control obese group (p < 0.001). Ad-36 Ab positivity and BMI ≥25 kg/m² were identified as independent predictors of PCOS in logistic regression analysis.

CONCLUSION

Ad-36 Ab positivity was significantly higher in the obese/overweight PCOS patients. Obesity can be prevented in patients with PCOS by treating Ad-36.

Adenovirus 5 produces obesity and adverse metabolic, morphological, and functional changes in the long term in animals fed a balanced diet or a high-fat diet: a study on hamsters

Adenovirus 5 (Ad-5) infection is a common cause of acute respiratory infections and the main vector used in gene therapy. There are few studies on the relationship of Ad-5 to obesity. In the present study, we evaluated the chronic effects of Ad-5 infection on golden (Syrian) hamsters fed either a balanced diet (BD) or a high-fat diet (HFD). After a single inoculation with Ad-5 (1 × 10⁷ pfu), the body weight of the animals was measured weekly. Medium-term (22 weeks) serum biochemical analyses and long-term (44 weeks) liver morphology, adiposity, and locomotive functionality (movement velocity) assessments were carried out. In the animals fed the BD, adenovirus infection produced hyperglycemia and hyperlipidemia. In the long term, it produced a 57% increase in epididymal pad fat and a 30% body weight gain compared with uninoculated animals. In addition, morphological changes related to non-alcoholic fatty liver disease (NAFLD) were observed. The animals fed the HFD had similar but more severe changes. In addition, the hamsters presented an obesity paradox: at the end of the study, the animals that had the most morphological and functional changes (significantly reduced movement velocity) had the lowest body weight. Despite the fact that an HFD appears to be a more harmful factor in the long term than adenovirus infection alone, infection could increase the severity of harmful effects in individuals with an HFD. Epidemiological studies are needed to evaluate the effect of adenovirus as a precursor of chronic liver and cardiovascular diseases, including the chronic effects of gene therapy.

Future Pharmacotherapy for Obesity: New Anti-obesity Drugs on the Horizon

PURPOSE OF REVIEW

Obesity is a global health crisis with detrimental effects on all organ systems leading to worsening disease state and rising costs of care. Persons with obesity failing lifestyle therapies need to be escalated to appropriate pharmacological treatment modalities, medical devices, and/or bariatric surgery if criteria are met and more aggressive intervention is needed. The progression of severe obesity in the patient population coupled with related co-morbidities necessitates the development of novel therapies for the treatment of obesity. This development is preceded by increased understanding of the underpinnings of energy regulation and neurohormonal pathways involved in energy homeostasis.

RECENT FINDINGS

Though there are approved anti-obesity drugs available in the USA, newer drugs are now in the pipeline for development given the urgent need. This review focuses on anti-obesity drugs in the pipeline including centrally acting agents (setmelanotide, neuropeptide Y antagonist [velneperit], zonisamide-bupropion [Empatic], cannabinoid type-1 receptor blockers), gut hormones and incretin targets (new glucagon-like-peptide-1 [GLP-1] analogues [semaglutide and oral equivalents], amylin mimetics [davalintide, dual amylin and calcitonin receptor agonists], dual action GLP-1/glucagon receptor agonists [oxyntomodulin], triple agonists [tri-agonist 1706], peptide YY, leptin analogues [combination pramlintide-metreleptin]), and other novel targets (methionine aminopeptidase 2 inhibitor [beloranib], lipase inhibitor [cetilistat], triple monoamine reuptake inhibitor [tesofensine], fibroblast growth factor 21), including anti-obesity vaccines (ghrelin, somatostatin, adenovirus36). With these new drugs in development, anti-obesity therapeutics have potential to vastly expand allowing better treatment options and personalized approach to obesity care.

Anti-ghrelin antibodies in appetite suppression: recent advances in obesity pharmacotherapy

Obesity is a medical condition caused by accumulated excess body fat with negative impact on patients’ health, including decreased life expectancy. It has become a major health problem in most developed and developing countries, since the worldwide prevalence of obesity nearly doubled during the last 30 years. Consequently, novel treatments focusing on obesity are being investigated. Potential targets include several pathophysiological mechanisms involved in appetite control affecting multiple organ systems, like adipose tissue; some cell types in the stomach and gut; pancreas; thyroid gland; several hypothalamic areas; and centers located in the brainstem. One of the most important orexigenic neuropeptides is ghrelin, which is produced and secreted primarily by ghrelin cells located in the stomach and duodenum. In humans, plasma ghrelin levels rise when the stomach is empty and fall shortly after meal ingestion. In fat tissue, ghrelin increases fat storage. In the brain, it exerts its orexigenic action through activation of NPY/AgRP neurons in the arcuate nucleus. From the pharmacological point of view, it seems that opposing ghrelin activity could be used as a therapeutic principle in treating obesity. The principal idea of antiobesity drugs is to augment anorexigenic and lipolytic signaling, or to block orexigenic and lipogenic mediators. Recent studies have shown that therapeutic vaccines could be a new approach in the development of antiobesity medications. A vaccine should provoke an immune response to a specific causal factor for a particular disease. Several types of anti-ghrelin vaccines have been developed so far, with significant immune response in terms of rising anti-ghrelin antibodies. However, in the only clinical trial performed yet, the results were disappointing, showing no additional weight loss in the study group. Until now, several studies have demonstrated the “proof of concept”, but more studies are required to develop prophylactic and therapeutic vaccines to prevent and/or cure obesity.

Adenovirus 36 and Obesity: An Overview

There is an epidemic of obesity starting about 1980 in both developed and undeveloped countries definitely associated with multiple etiologies. About 670 million people worldwide are obese. The incidence of obesity has increased in all age groups, including children. Obesity causes numerous diseases and the interaction between genetic, metabolic, social, cultural and environmental factors are possible cofactors for the development of obesity. Evidence emerging over the last 20 years supports the hypothesis that viral infections may be associated with obesity in animals and humans. The most widely studied infectious agent possibly linked to obesity is adenovirus 36 (Adv36). Adv36 causes obesity in animals. In humans, Adv36 associates with obesity both in adults and children and the prevalence of Adv36 increases in relation to the body mass index. In vivo and in vitro studies have shown that the viral E4orf1 protein (early region 4 open reading frame 1, Adv) mediates the Adv36 effect including its adipogenic potential. The Adv36 infection should therefore be considered as a possible risk factor for obesity and could be a potential new therapeutic target in addition to an original way to understand the worldwide rise of the epidemic of obesity. Here, the data indicating a possible link between viral infection and obesity with a particular emphasis to the Adv36 will be reviewed.