Comparative analysis of the serum microbiome of HIV infected individuals

Deciphering HIV-associated inflammation: microbiome's influence and experimental insights

PURPOSE OF REVIEW

To review novel experimental approaches for studying host:microbe interactions and their role in intestinal and systemic inflammation in people living with HIV (PLWH).

RECENT FINDINGS

Inflammation in PLWH is impacted by interactions between the microbiome, the intestinal epithelium, and immune cells. This complex interplay is not fully understood and requires a variety of analytical techniques to study. Using a multiomic systems biology approach provides hypothesis generating data on host:microbe interactions that can be used to guide further investigation. The direct interactions between host cells and microbes can be elucidated using peripheral blood mononuclear cells (PBMCs), lamina propria mononuclear cells (LPMC's) or human intestinal organoids (HIO). Additionally, the broader relationship between the host and the microbiome can be explored using animal models such as nonhuman primates and germ-free and double humanized mice.

SUMMARY

To explore complex host:microbe relationships, hypotheses are generated and investigations are guided by multiomic data, while causal components are identified using in-vitro and in-vivo assays.

Gut Microbiota and Other Factors Associated With Increased Regulatory T Cells in Hiv-exposed Uninfected Infants

HIV-exposed uninfected infants (HEU) have higher infectious morbidity than HIV-unexposed infants (HUU). HEU have multiple immune defects of unknown origin. We hypothesized that HEU have higher regulatory T cells (Treg) than HUU, which may dampen their immune defenses against pathogens. We compared 25 Treg subsets between HEU and HUU and sought the factors that may affect Treg frequencies. At birth, 3 Treg subsets, including CD4 + FOXP3 + and CD4 + FOXP3 + CD25+, had higher frequencies in 123 HEU than 117 HUU and 3 subsets were higher in HUU. At 28 and 62 weeks of life, 5 Treg subsets were higher in HEU, and none were higher in HUU. The frequencies of the discrepant Treg subsets correlated at birth with differential abundances of bacterial taxas in maternal gut microbiome and at subsequent visits in infant gut microbiomes. In vitro, bacterial taxa most abundant in HEU expanded Treg subsets with higher frequencies in HEU, recapitulating the in vivo observations. Other factors that correlated with increased Treg were low maternal CD4 + T cells in HEU at birth and male sex in HUU at 28 weeks. We conclude that maternal and infant gut dysbiosis are central to the Treg increase in HEU and may be targeted by mitigating interventions.

Microbiome analysis of circulating bacterial extracellular vesicles in obsessive-compulsive disorder

AIM

The present study examined the microbiome abundance and composition of drug-naive or drug-free patients with obsessive-compulsive disorder (OCD) compared with healthy controls. In addition, in the OCD group, the microbiome composition was compared between early-onset and late-onset OCD.

METHODS

Serum samples were collected from 89 patients with OCD and 107 age- and sex-matched healthy controls. Bacterial DNA was isolated from bacteria-derived extracellular vesicles in serum and then amplified and quantified using primers specific to the V3-V4 hypervariable region of the 16S ribosomal RNA gene. The 16S ribosomal DNA gene amplicon sequencing was performed.

RESULTS

The pooled estimate showed that α-diversity was significantly reduced in patients with OCD compared with that in healthy controls (PShannon  = 0.00015). In addition, a statistically significant difference was observed in β-diversity between patients with OCD and healthy controls at the order (P = 0.012), family (P = 0.003), genus (P < 0.001), and species (P = 0.005) levels. In the microbiome composition, Pseudomonas, Caulobacteraceae (f), Streptococcus, Novosphingobium, and Enhydrobacter at the genus level were significantly less prevalent in patients with OCD than in controls. In addition, among patients with OCD, the microbial composition in the early-onset versus late-onset types was significantly different with respect to the genera Corynebacterium and Pelomonas.

CONCLUSION

The present study showed an aberrant microbiome in patients with OCD, suggesting a role of the microbiota-brain interaction in the pathophysiology of OCD. Further longitudinal studies with larger sample sizes adjusting for various confounders are warranted.

Skin microbiome profile in people living with HIV/AIDS in Cameroon

The presence of pathogens and the state of diseases, particularly skin diseases, may alter the composition of human skin microbiome. HIV infection has been reported to impair gut microbiome that leads to severe consequences. However, with cutaneous manifestations, that can be life-threatening, due to the opportunistic pathogens, little is known whether HIV infection might influence the skin microbiome and affect the skin homeostasis. This study catalogued the profile of skin microbiome of healthy Cameroonians, at three different skin sites, and compared them to the HIV-infected individuals. Taking advantage on the use of molecular assay coupled with next-generation sequencing, this study revealed that alpha-diversity of the skin microbiome was higher and beta-diversity was altered significantly in the HIV-infected Cameroonians than in the healthy ones. The relative abundance of skin microbes such as Micrococcus and Kocuria species was higher and Cutibacterium species was significantly lower in HIV-infected people, indicating an early change in the human skin microbiome in response to the HIV infection. This phenotypical shift was not related to the number of CD4 T cell count thus the cause remains to be identified. Overall, these data may offer an important lead on the role of skin microbiome in the determination of cutaneous disease state and the discovery of safe pharmacological preparations to treat microbial-related skin disorders.

Decrypting biological hallmarks of aging in people with HIV

PURPOSE OF REVIEW

HIV infection adds further complexity to the heterogenous process of aging. In this focused review, we examine and discuss recent advances to better elucidate mechanisms of biological aging perturbed and accelerated in the context of HIV, particularly among those with viral suppression through the benefits of antiretroviral therapy (ART). New hypotheses from these studies are poised to provide an improved understanding of multifaceted pathways that converge and likely form the basis for effective interventions toward successful aging.

RECENT FINDINGS

Evidence to date suggests multiple mechanisms of biological aging impact people living with HIV (PLWH). Recent literature delves and expands on how epigenetic alterations, telomere attrition, mitochondrial perturbations, and intercellular communications may underpin accelerated or accentuated aging phenotypes and the disproportionate prevalence of age-related complications among PLWH. Although most hallmarks of aging are likely exacerbated in the setting of HIV, ongoing research efforts are providing new insight on the collective impact these conserved pathways may have in the aging disease processes.

SUMMARY

New knowledge on underlying molecular disease mechanisms impacting people aging with HIV are reviewed. Also examined are studies that may facilitate the development and implementation of effective therapeutics and guidance on improving geriatric HIV clinical care.

Generation of dysbiotic microbiota in cutaneous Leishmaniasis and enhancement of skin inflammation

Cutaneous Leishmaniasis (CL) affects millions of people globally and has a significant impact on morbidity and mortality. Innate immune mediators are likely to influence the clinical phenotype of CL through primary responses that restrict or facilitate parasite spread. The aim of the study was to bring to attention the significance of microbiota in the development of CL and emphasized the necessity of including the role of microbiota in CL while promoting a One Health approach for managing diseases. To achieve this, we used 16S amplicon metagenome sequencing and QIIME2 pipeline to analyze the microbiome composition of CL-infected patients compared to non-infected, healthy subjects. 16S sequencing analysis showed serum microbiome was dominated by Firmicutes, Proteobacteria, Bacteroidota, and Actinobacteria. CL-infected individuals, Proteobacteria were the most prevalent (27.63 ± 9.79), with the relative abundance (10.73 ± 5.33) of Proteobacteria in control. Bacilli class was found to be the most prevalent in healthy controls (30.71 ± 8.44) while (20.57 ± 9.51) in CL-infected individuals. The class Alphaproteobacteria was found to be more in CL-infected individuals (5.47 ± 2.07) as compared to healthy controls (1.85 ± 0.39). The CL-infected individuals had a significantly lower relative abundance of the Clostridia class (p < 0.0001). An altered serum microbiome of CL infection and higher microbial abundance in the serum of healthy individuals was observed.