HIF1α-Regulated Expression of the Fatty Acid Binding Protein Family Is Important for Hypoxic Reactivation of Kaposi's Sarcoma-Associated Herpesvirus

Epigenetic Reprogramming of Kaposi's Sarcoma-Associated Herpesvirus during Hypoxic Reactivation

The biphasic life cycle (latent and lytic) of Kaposi's sarcoma-associated Herpesvirus (KSHV) is regulated by epigenetic modification of its genome and its associated histone proteins. The temporal events driving epigenetic reprogramming of the KSHV genome on initial infection to establish latency has been well studied, but the reversal of these epigenetic changes during lytic replication, especially under physiological conditions such as hypoxia, has not been explored. In this study, we investigated epigenetic reprogramming of the KSHV genome during hypoxic reactivation. Hypoxia induced extensive enrichment of both transcriptional activators and repressors on the KSHV genome through H3K4Me3, H3K9Me3, and H3K27Me3, as well as histone acetylation (H3Ac) modifications. In contrast to uniform quantitative enrichment with modified histones, a distinct pattern of RTA and LANA enrichment was observed on the KSHV genome. The enrichment of modified histone proteins was due to their overall higher expression levels, which was exclusively seen in KSHV-positive cells. Multiple KSHV-encoded factors such as LANA, RTA, and vGPCR are involved in the upregulation of these modified histones. Analysis of ChIP-sequencing for the initiator DNA polymerase (DNAPol1α) combined with single molecule analysis of replicated DNA (SMARD) demonstrated the involvement of specific KSHV genomic regions that initiate replication in hypoxia.

Correlation between adipocyte fatty acid binding protein and glucose dysregulation is closely associated with obesity and metabolic syndrome: A cohort of Han Chinese population from Yunnan plateau

The present study investigated the correlation of plasma A-FABP with glucose dysregulation under different body mass index (BMI) and metabolic states in a Han Chinese population from Yunnan plateau. We cross-sectionally analyzed data from the China Multi Ethnic Cohort, Yunnan province. Participants were divided into two groups. Group A contained 297 obese individuals with metabolic syndrome (MetS). Group B contained 326 age-, sex-, and region-matched normal BMI subjects without MetS. Glucose dysregulation was defined as elevated fasting plasma glucose (FPG) (FPG ≥ 5.6 mmol/L or current use of oral hypoglycemic agents or insulin). Circulating A-FABP were assayed by ELISA method. Binary and multiple regression analyses were preformed to evaluate the correlation between A-FABP and glucose dysregulation. Plasma A-FABP level was significantly higher in group A compared with group B (p < 0.001). Plasma A-FABP level correlated positively with elevated FPG in group A (r = 0.120, p = 0.039), but negatively with elevated FPG in group B (r = -0.115, p = 0.039). Multiple logistic regression analysis revealed that A-FABP was an independent predictor for elevated FPG in group A (β, 0.028; 95% CI, 1.001-1.056; p < 0.05), but not in group B (β, -0.008; 95% CI, 0.882-1.117; p > 0.05). In this study, A-FABP was an independent risk factor for glucose dysregulation in obese individuals with MetS living in the Yunnan plateau, but not for those without obesity and MetS.

Acute Hypoxia Alters Extracellular Vesicle Signatures and the Brain Citrullinome of Naked Mole-Rats (Heterocephalus glaber)

Peptidylarginine deiminases (PADs) and extracellular vesicles (EVs) may be indicative biomarkers of physiological and pathological status and adaptive responses, including to diseases and disorders of the central nervous system (CNS) and related to hypoxia. While these markers have been studied in hypoxia-intolerant mammals, in vivo investigations in hypoxia-tolerant species are lacking. Naked mole-rats (NMR) are among the most hypoxia-tolerant mammals and are thus a good model organism for understanding natural and beneficial adaptations to hypoxia. Thus, we aimed to reveal CNS related roles for PADs in hypoxia tolerance and identify whether circulating EV signatures may reveal a fingerprint for adaptive whole-body hypoxia responses in this species. We found that following in vivo acute hypoxia, NMR: (1) plasma-EVs were remodelled, (2) whole proteome EV cargo contained more protein hits (including citrullinated proteins) and a higher number of associated KEGG pathways relating to the total proteome of plasma-EVs Also, (3) brains had a trend for elevation in PAD1, PAD3 and PAD6 protein expression, while PAD2 and PAD4 were reduced, while (4) the brain citrullinome had a considerable increase in deiminated protein hits with hypoxia (1222 vs. 852 hits in normoxia). Our findings indicate that circulating EV signatures are modified and proteomic content is reduced in hypoxic conditions in naked mole-rats, including the circulating EV citrullinome, while the brain citrullinome is elevated and modulated in response to hypoxia. This was further reflected in elevation of some PADs in the brain tissue following acute hypoxia treatment. These findings indicate a possible selective role for PAD-isozymes in hypoxia response and tolerance.