Biology subjects

Rashid, R. B.

Publications and source records attributed to Rashid, R. B..

3 recordsLinked to original sources

bioRxiv2024

A maternal high-fat diet predisposes to infant lung disease via increased neutrophil-mediated IL-6 trans-signaling

Poor maternal diet during pregnancy predisposes to severe lower respiratory tract infections (sLRI) in infancy, which in turn, increases childhood asthma risk, however the underlying mechanisms remain poorly understood. Here, we show that the offspring of high fat diet (HFD)-fed mothers ( HFD-reared pups) developed a sLRI following pneumovirus inoculation in early-life and subsequent asthma in later-life upon allergen exposure. Prior to infection, HFD-reared pups developed microbial dysbiosis and low-grade systemic inflammation (LGSI), characterized by hyper-granulopoiesis in the liver and elevated inflammatory cytokine expression, most notably IL-17A, IL-6 and sIL-6R (indicative of IL-6 trans-signaling) in the circulation and multiple organs, but most prominently the liver. Inhibition of IL-6 trans-signaling, using sgp130Fc transgenic mice or via specific genetic deletion of IL-6Ra on neutrophils, conferred protection against both diseases. Taken together, our findings suggest that a maternal HFD induces neonatal LGSI that predisposes to sLRI and subsequent asthma via neutrophil-mediated IL-6 trans-signaling.

immunology↗

bioRxiv2023

Dual therapy with corticosteroid ablates the beneficial effect of DP2 antagonism in chronic experimental asthma.

BackgroundProstaglandin D2 (PGD2) signals via the DP1 and DP2 receptors. In Phase II trials, DP2 antagonism decreased airway inflammation and airway smooth muscle (ASM) area in patients with moderate-to-severe asthma, but in the Phase III clinical trials, DP2 antagonism failed to significantly lower the rate of exacerbations. Here, we hypothesised that DP2 antagonism resolves established ASM remodeling via endogenous PGD2/DP1 activation and that this beneficial effect is ablated by dual corticosteroid therapy. MethodsNeonatal mice were co-exposed to pneumonia virus of mice (PVM) and cockroach extract in early life to induce severe bronchiolitis, then re-infected with PVM and challenged to cockroach extract in adulthood to progress disease to chronic experimental asthma (CEA). The efficacy of DP2 antagonism monotherapy or various dual therapies was assessed in the setting of a rhinovirus (RV)-induced exacerbation. ResultsRV inoculation increased PGD2 release, mucus production, collagen deposition, transforming growth factor (TGF)-{beta}1 expression and type-2 inflammation. Treatment with a DP2 antagonist or DP1 agonist ablated the aforementioned phenotypes, increased type-1 immunity, and decreased ASM area. Dual DP1-DP2 antagonism or dual corticosteroid/DP2 antagonism, which attenuated endogenous PGD2 levels, prevented the resolution of ASM area induced by DP2 antagonism alone. The resolution of ASM remodelling following DP2 antagonism was mediated by IFN-{gamma} and associated with decreased TGF-{beta}1 expression. ConclusionDP2 antagonism resolved ASM remodelling via PGD2/DP1-mediated upregulation of interferon-{gamma} expression. Dual DP2 antagonism/corticosteroid therapy, as occurred in many of the human trials, suppressed PGD2 and IFN-{gamma} production, impairing the efficacy of DP2 antagonism.

immunology↗

bioRxiv2023

The maternal microbiome regulates infant respiratory disease susceptibility via intestinal Flt3L expression and plasmacytoid dendritic cell hematopoiesis

Severe lower respiratory infection (sLRI) are a major cause of infant morbidity and mortality, and predispose to later chronic respiratory diseases such as asthma. Poor maternal diet during pregnancy is a risk factor for sLRI in the offspring. Here we demonstrate in mice that a maternal low-fibre diet (LFD) disrupts plasmacytoid and conventional dendritic cell (DC) hematopoiesis in the offspring, predisposing to sLRI and subsequent asthma. The LFD alters the composition of the maternal milk microbiome and assembling infant gut microbiome, ablating the induction of a developmental wave of the non-redundant DC growth factor Flt3L by neonatal intestinal epithelial cells. Therapy with a propionate-producing bacteria isolated from the milk of high-fibre diet-fed mothers, or supplementation with propionate, confers protection against sLRI by restoring gut Flt3L expression and pDC hematopoiesis. Our findings identify a microbiome-dependent Flt3L axis in the gut that regulates pDC hematopoiesis in early life and confers disease resistance. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=51 SRC="FIGDIR/small/522516v1_ufig1.gif" ALT="Figure 1"> View larger version (15K): org.highwire.dtl.DTLVardef@1a39990org.highwire.dtl.DTLVardef@1b6fe67org.highwire.dtl.DTLVardef@f8440dorg.highwire.dtl.DTLVardef@13bc67e_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗