Biology subjects

Molloy, M.

Publications and source records attributed to Molloy, M..

4 recordsLinked to original sources

bioRxiv2026

Short-term dietary change rapidly remodels microbial community assemblages and reprogrammed systemic immune phenotypes

Diet is a major determinant of the gut microbiome and immune homeostasis, yet the extent to which short-term dietary interventions can remodel established microbial communities and reprogramme immune phenotypes following long-term western diet consumption remains poorly understood. Here, we investigated temporal dynamics of the gut microbiome, microbial metabolites, intestinal barrier function and local and systemic immune responses following diet switching. Mice were fed either a standard chow or a western diet for 8 weeks before remaining on these diets or switching to the alternate diet for 2 or 4 weeks. Long term consumption of chow and western diets resulted in distinct gut microbial communities and differences in intestinal permeability. Diet switching rapidly remodelled microbial community structure within two weeks, with substantial bidirectional changes in community composition. Despite these changes, the relative abundance of several taxa remained influenced by prior dietary exposure. In contrast, faecal SCFA profiles remained largely associated with long-term diet, indicating that microbial metabolic outputs were altered more slowly than microbial community composition. Mass cytometry revealed progressive remodelling of local (MLN) and systemic (PBMC and spleen) immune responses following dietary switching. Activation-associated immune phenotypes, including Ki67+ and PD-1+ B and T cells, inflammatory monocytes and ROR{gamma}t+ regulatory T cells, rapidly responded to diet switching, whereas overall B cells, regulatory T cells and effector memory T cells retained signatures of long-term dietary exposure. Together, these findings demonstrate distinct temporal dynamics across the diet-microbiome-immune axis, whereby gut microbial composition and immune activation states remain highly plastic, while microbial metabolic outputs and several memory and regulatory immune phenotypes exhibit persistent dietary imprinting. These findings highlight the potential utility of short-term dietary interventions to modulate host-microbiome interactions and immune homeostasis.

immunology↗

bioRxiv2020

Proteome analysis of human visceral and subcutaneous adipocytes identifies depot-specific heterogeneity at metabolic control points

Adipose tissue is a primary regulator of energy balance and metabolism. The distribution of adipose tissue depots is of clinical interest because the accumulation of upper-body subcutaneous (ASAT) and visceral adipose tissue (VAT) is associated with cardiometabolic diseases, whereas lower-body gluteal-femoral adipose tissue (GFAT) appears to be protective. There is heterogeneity in morphology and metabolism of adipocytes obtained from different regions of the body, but detailed knowledge of the constituent proteins in each depot is lacking. Here, we determined the human adipocyte proteome from ASAT, VAT and GFAT using high-resolution SWATH mass spectrometry proteomics. We quantified 4220 proteins in adipocytes, and 2329 proteins were expressed in all three adipose depots. Comparative analysis revealed significant differences between adipocytes from different regions (6 and 8% when comparing VAT vs. ASAT and GFAT, 3% when comparing ASAT vs. GFAT), with marked differences in proteins that regulate metabolic functions. The VAT adipocyte proteome was overrepresented with proteins of glycolysis, lipogenesis, oxidative stress and mitochondrial dysfunction. The GFAT adipocyte proteome predicted activation of PPAR, fatty acid and BCAA oxidation, enhanced TCA cycle flux and oxidative phosphorylation, which was supported by metabolomic data obtained from adipocytes from the same patient donors. Together, this proteomic analysis provides an important resource and novel insights that enhance the understanding of metabolic heterogeneity in the regional adipocytes of humans.

physiology↗

bioRxiv2019

Protein Expression Patterns in ovarian cancer cells Associated with Monofunctional Platinums Treatment

Platinum drugs cisplatin and carboplatin, given in combination with paclitaxel, constitute the standard chemotherapy against ovarian cancer (OC). Oc chemoresistance is a major obstacle to effective treatment, but knowledge of the mechanisms that underlie it remains incomplete. We thus sought to discover key proteins associated with platinum resistance by comparing A2780 OC cells with A2780cisR cells (resistant cells derived from the A2780 line) to identify proteins with markedly altered expression levels in the resistant cells. We also determined which proteins in these cells had altered expression in response to treatment with either designed monofunctional platinum alone or a combination with cisplatin with selected phytochemical therapeutic agents.\n\nWe thus performed proteomic analysis using 2D-gel electrophoresis A2780 and A2780cisR to identify proteins with differential expression; these were eluted and analysed by mass spectrometry to identify them. A total of 122 proteins were found to be differentially expressed between A2780 and A2780cisR cell lines in the absence of any drug treatment. Among them, levels of 27 proteins in A2780cisR cell line were further altered (up-or down-regulated) in response to one or more of the drug treatments. We then investigated primary OC tissue RNA expression levels (compared to l ovarian tissue) of genes coding for these candidate 27 proteins using publically available datasets (The Cancer Genome Atlas). We assessed how expression of these genes in OC tissue associates with patient survival using Cox Proportional Hazard (PH) regression models to determine relative risk of death associated with each factor. Our Cox PH regression-based machine learning method confirmed a significant relationship of mortality with altered expression of ARHGDIA, CCT6A and HISTIH4F genes. This indicated that these genes affect OC patient survival, i.e., provided mechanistic evidence, in addition to that of the clinical traits, that these genes may be critical mediators of the processes that underlie OC progression and mortality.\n\nThus, we identified differentially expressed proteins that are implicated in platinum-based chemotherapy resistance mechanisms which may serve as resistance biomarkers. These drug resistance associated proteins may also serve as potential OC therapeutic targets whose blockade may enhance the effectiveness of platinum based drugs.

cancer biology↗

bioRxiv2018

A novel role for the HLH protein Inhibitor of Differentiation 4 (ID4) in the DNA damage response in basal-like breast cancer.

Basal-like breast cancer (BLBC) is a poorly characterised, heterogeneous disease. Patients are diagnosed with aggressive, high-grade tumours and often relapse with chemotherapy resistance. Detailed understanding of the molecular underpinnings of this disease is essential to the development of personalised therapeutic strategies. Inhibitor of Differentiation 4 (ID4) is a helix-loop-helix transcriptional regulator required for mammary gland development. ID4 is overexpressed in a subset of BLBC patients, associating with a stem-like poor prognosis phenotype, and is necessary for the growth of cell line models of BLBC, through unknown mechanisms. Here, we have defined a molecular mechanism of action for ID4 in BLBC and the related disease highgrade serous ovarian cancer (HGSOV), by combining RIME proteomic analysis and ChIP-Seq mapping of genomic binding sites. Remarkably, these studies have revealed novel interactions with DNA damage response proteins, in particular, mediator of DNA damage checkpoint protein 1 (MDC1). Through MDC1, ID4 interacts with other DNA repair proteins ({gamma}H2AX and BRCA1) at fragile chromatin sites. ID4 does not affect transcription at these sites, instead binding to chromatin following DNA damage and regulating DNA damage signalling. Clinical analysis demonstrates that ID4 is amplified and overexpressed at a higher frequency in BRCA1-mutant BLBC compared with sporadic BLBC, providing genetic evidence for an interaction between ID4 and DNA damage repair pathways. These data link the interactions of ID4 with MDC1 to DNA damage repair in the aetiology of BLBC and HGSOV.

cancer biology↗