Biology subjects

Abrahams, V. M.

Publications and source records attributed to Abrahams, V. M..

3 recordsLinked to original sources

bioRxiv2024

Quantitative proteomics reveals differential extracellular vesicle cargo from M1 and M2 monocyte-derived human macrophages

Extracellular vesicles (EVs) mediate intercellular communication by carrying molecular cargo that facilitate diverse physiological processes. Macrophages, playing central roles in immune responses, release EVs that modulate various cellular functions. Given the distinct roles of M1 and M2 macrophage states, understanding the proteomic profiles of their EVs is important for elucidation of EV-mediated signalling and identifying potential biomarkers for diseases involving macrophage polarisation. We employed quantitative proteomics combined with bioinformatics to characterise the proteomic profile of EVs released by M1 and M2 monocyte-derived macrophages. We identified 1,731 proteins in M1/M2 EVs, 132 of which were significantly differentially between M1 and M2. Proteomic data, together with pathway analysis, found that M1/M2 macrophage EV cargo relate to cellular source, and may play roles in shaping immune responses, with M1 EV cargo associated with promotion of pro-inflammatory and antiviral functions, while M2 EV cargo associated with immune regulation and tissue repair. M1 EV cargo was associated with cytokine/chemokine signalling pathways, DNA damage, methylation, and oxidative stress. M2 EV cargo were associated with macrophage alternative-activation signalling pathways, antigen presentation, and lipid metabolism. We also report that macrophage EVs carry metallothioneins, and other related proteins involved in response to metals and oxidative stress.

immunology↗

bioRxiv2023

TLR8-Activating miR-146a-3p is an Intermediate Signal Contributing to Fetal Membrane Inflammation in Response to Bacterial LPS

Preterm birth is the largest contributor to neonatal morbidity and is often associated with chorioamnionitis, defined as inflammation/infection of the fetal membranes (FMs). Chorioamnionitis is characterized by neutrophil infiltration of the FMs and is associated with elevated levels of the neutrophil chemoattractant, interleukin (IL)-8, and the proinflammatory cytokine, IL-1{beta}. While FMs can respond to infections through innate immune sensors, such as Toll-like receptors (TLRs), the downstream mechanisms by which chorioamnionitis arises are not fully understood. A novel group of non-classical microRNAs (miR-21a, miR-29a, miR-146a-3p, Let-7b) function as endogenous danger signals by activating the ssRNA viral sensors TLR7 and TLR8. In this study, the pro-inflammatory roles of TLR7/TLR8-activating miRs were examined as mediators of FM inflammation in response to bacterial lipopolysaccharide (LPS) using an in vitro human FM explant system, an in vivo mouse model of pregnancy, and human clinical samples. Following LPS exposure, miR-146a-3p was significantly increased in both human FM explants and in wildtype mouse FMs. Expression of miR-146a-3p was also significantly elevated in FMs from women with preterm birth and chorioamnionitis. FM IL-8 and inflammasome-mediated IL-1{beta} production in response to LPS was dependent on miR-146a-3p and TLR8, downstream of TLR4 activation. In wildtype mice, LPS exposure increased FM IL-8 and IL-1{beta} production and induced preterm birth. In TLR7-/-/TLR8-/-mice, LPS exposure was able to initiate, but not sustain preterm birth, and FM inflammation was reduced. Together, we demonstrate a novel signaling mechanism at the maternal-fetal interface in which TLR8-activating miR-146a-3p acts as an intermediate danger signal to drive FM inflammasome-dependent and -independent mechanisms of inflammation and thus, may play a role in chorioamnionitis and subsequent preterm birth.

immunology↗

bioRxiv2022

Distinct non-coding RNA cargo of extracellular vesicles from M1 and M2 human primary macrophages

Macrophages are important antigen presenting cells which can release extracellular vesicles (EVs) carrying functional cargo including non-coding RNAs. Macrophages can be broadly classified into M1 classical and M2 alternatively-activated macrophages. M1 macrophages have been linked with inflammation-associated pathologies, whereas a switch towards an M2 phenotype indicates resolution of inflammation and tissue regeneration. Here, we provide the first comprehensive analysis of the small RNA cargo of EVs from human M1 and M2 primary macrophages. Using small RNA sequencing, we identified several types of small non-coding RNAs in M1 and M2 macrophage EVs including miRNAs, isomiRs, tRNA fragments, piRNA, snRNA, snoRNA and Y-RNA fragments. Distinct differences were observed between M1 and M2 EVs, with higher relative abundance of miRNAs, and lower abundance of tRNA fragments in M1 compared to M2 EVs. MicroRNA-target enrichment analysis identified several gene targets involved in gene expression and inflammatory signalling pathways. EVs were also enriched in tRNA fragments, primarily originating from the 5 end or the internal region of the full length tRNAs, many of which were differentially abundant in M1 and M2 EVs. Similarly, several other small non-coding RNAs, namely piRNAs, snRNAs, snoRNAs and Y-RNA fragments, were differentially enriched in M1 and M2 EVs; we discuss their putative roles in macrophage EVs. In conclusion, we show that M1 and M2 macrophages release EVs with distinct RNA cargo, which has the potential to contribute to the unique effect of these cell subsets on their microenvironment.

immunology↗