Proof-of-concept for a virus-induced obesity vaccine; vaccination against the obesity agent adenovirus 36.

Human adenovirus 36 (Ad36) is positively associated with obesity in humans and animals. Ad36 infection is characterized by increased adiposity and inflammation. To investigate the possibility that a prophylactic vaccine candidate might protect against Ad36-induced obesity and inflammation, we purified Ad36 and ultraviolet-irradiated virus to obtain a vaccine candidate. After immunizing the mice with the vaccine candidate (vaccinated group), live Ad36 was injected into mice as a challenge test. Unvaccinated mice (control group) were immunized with phosphate-buffered saline and then challenged with live Ad36. Fourteen weeks after challenge, we compared adiposity and inflammation in vaccinated and control mice. The control group showed 17% greater body weight and 20% more epididymal fats compared with the vaccinated group. In addition, the vaccinated group had decreased serum levels of pro-inflammatory cytokines, and infiltrated immune cells, especially M1 macrophages, in fat tissue. Therefore, the vaccine candidate for Ad36 was able to protect against Ad36-increased body weight and fat as well as inflammatory states after challenge. These results provide proof-of-concept for prophylactic vaccination against virus-induced adiposity.

Genomic stability of adipogenic human adenovirus 36.

Human adenovirus Ad36 increases adiposity in several animal models, including rodents and non-human primates. Importantly, Ad36 is associated with human obesity, which has prompted research to understand its epidemiology and to develop a vaccine to prevent a subgroup of obesity. For this purpose, understanding the genomic stability of Ad36 in vivo and in vitro infections is critical. Here, we examined whether in vitro cell passaging over a 14-year period introduced any genetic variation in Ad36. We sequenced the whole genome of Ad36-which was plaque purified in 1998 from the original strain obtained from American Type Culture Collection, and passaged approximately 12 times over the past 14 years (Ad36-2012). This DNA sequence was compared with a previously published sequence of Ad36 likely obtained from the same source (Ad36-1988). Compared with Ad36-1988, only two nucleotides were altered in Ad36-2012: a T insertion at nucleotide 1862, which may induce early termination of the E1B viral protein, and a T➝C transition at nucleotide 26 136. Virus with the T insertion (designated Ad36-2012-T6) was mixed with wild-type virus lacking the T insertion (designated Ad36-2012-T5) in the viral stock. The transition at nucleotide 26 136 does not change the encoded amino acid (aspartic acid) in the pVIII viral protein. The rate of genetic variation in Ad36 is ∼2.37 × 10(-6) mutations/nucleotide/passage. Of particular importance, there were no mutations in the E4orf1 gene, the critical gene for producing obesity. This very-low-variation rate should reduce concerns about genetic variability when developing Ad36 vaccines or developing assays for detecting Ad36 infection in populations.

Association of human adenovirus-36 in overweight Korean adults.

BACKGROUND: Although human adenovirus-36 (Ad-36) has been reported to be associated with obesity in US adults and children, Korean children and the Italian population, the association has not been found in Dutch or Belgian populations or in US military subjects. Therefore, we examined whether Ad-36 infection is associated with obesity in Korean adults. METHODS: A total of 540 age- and sex-matched individuals, who were normal weight, overweight or obese, were selected from participants in routine health examinations at the Ewha Womans University Medical Center. Overweight participants were defined as those with a body mass index (BMI) of 23 ≤ BMI<25 kg m(-2) and obese subjects were those with BMI ≥ 25 kg m(-2), according to the International Obesity Task Force definition. Ad-36 antibody was measured using a serum neutralization assay. RESULTS: Although more overweight participants than normal or obese subjects tested positive for the Ad-36 antibody (40%, 32.8% and 30%, respectively), the differences were not significant. The participants who tested positive for Ad-36 antibody had lower levels of triglycerides (TG) in each of the three groups, higher total cholesterol (TC) in the obese group and higher high-density lipoprotein-cholesterol (HDL-C) in both the normal and obese groups. The odds ratio (OR) for Ad-36 antibody positivity was greater in overweight than in normal subjects (OR=2.03; 95% confidence interval (CI), 1.16-3.55) after adjusting for age, sex and waist circumference. However, this OR was non-significant in the obese group (OR=1.56; 95% CI, 0.67-3.67). CONCLUSION: Ad-36 seems to be strongly associated with overweight, but not obese, Korean adults.

Novel genes and cellular pathways related to infection with adenovirus-36 as an obesity agent in human mesenchymal stem cells.

OBJECTIVE: The objective of this study was to investigate the molecular mechanisms underlying adenovirus-36 (Ad-36)-induced obesity by the identification of novel genes and cellular pathways. DESIGN: Viral growth, intracellular lipid accumulation and gene expression profiles were determined in human mesenchymal stem cells (hMSCs) infected with Ad-36 or Ad-2. A microarray assay and gene set enrichment analysis (GSEA) were performed to assess alterations in global gene expression profiles. RESULTS: Ad-36, but not Ad-2, induced lipid accumulation and upregulated adipogenesis-related genes. There was no difference in viral growth between Ad-36 infection and Ad-2 infection in hMSCs. GSEA revealed that Ad-36 infection was more frequently associated with activation of novel pathways, including the PPAR-gamma signaling pathway, and inflammation compared with Ad-2 infection, raising the possibility that these pathways may be key regulators of Ad-36-induced adipogenesis. CONCLUSION: This study may help foster a better understanding of the roles of several cellular factors in Ad-36-induced obesity.

Association between human adenovirus-36 and lipid disorders in Korean schoolchildren.

BACKGROUND: Although the human adenovirus-36 (Ad-36) has been associated with obesity and related lipid disorders in the United States, this association has yet to be identified in other countries. Therefore, we tried to determine whether Ad-36 is associated with obesity or lipid disorders in Korean schoolchildren. METHOD: A total of 318 Korean schoolchildren aged 6-15 years, who participated in the Ewha Womans University Obesity Research Study, were selected for a community-based cohort study. Non-obese and obese were defined as body mass index (BMI) <85th and > or = 95th percentiles of the Korean reference BMI-for-age curves, respectively, according to International Obesity Task Force definitions. The cutoff points for lipid disorders were modified from the age-modified standards of the National Cholesterol Education Program (NCEP)-Adult Treatment Panel (ATP) III metabolic syndrome criteria. The Ad-36 antibody was measured using a serum neutralization assay. RESULTS: More obese participants than non-obese participants tested positive for the Ad-36 antibody (28.57 vs 13.56%, respectively; P = 0.0174). Within the obese group, the participants who tested positive for the Ad-36 antibody had higher levels of triglycerides (TG) and total cholesterol than those who tested negative for the Ad-36 antibody (P<0.001). However, these associations were not present in the non-obese group. The unadjusted odds ratio (OR) for Ad-36 antibody positivity was greater in obese participants than non-obese participants (OR = 2.550, 95% confidence interval (CI): 1.154-5.633). However, this OR seemed to be nonsignificant when age, sex and lipid variables were included in the analysis (OR = 1.752, 95% CI: 0.763-4.020). The unadjusted OR for the elevated TG was significantly higher in participants who were Ad-36 antibody-positive than those who were Ad-36 antibody-negative (OR = 2.511, 95% CI: 1.448-4.353). This trend remained constant even after adjustment for age, sex and obesity (OR = 2.328, 95% CI: 1.296-4.181). CONCLUSION: Ad-36 seems to be strongly associated with lipid disorders in Korean schoolchildren regardless of obesity.