Biology subjects

Alaniz, R. C.

Publications and source records attributed to Alaniz, R. C..

3 recordsLinked to original sources

bioRxiv2025

NRF2-Dependent Anti-Inflammatory Activity of Indole via Cell Surface Receptor Signaling in Murine Macrophages

In this study, we report indoles anti-inflammatory effects to be AhR-independent in RAW 264.7 macrophages. To explore the possibility of indoles surface-receptor mediated signaling, we developed an indole-bovine serum albumin conjugate (I3B), which primarily engage cell surface receptors and has limited intracellular engagement. Treatment with 10 M of I3B led to a comparable reduction of TNF- production in LPS-stimulated RAW 264.7 macrophages to that observed with 500 M of free indole. Transcriptome profiling of I3B-treated LPS-stimulated RAW 264.7 macrophages revealed, I3B blunts pro-inflammatory response and induces gene signatures consistent with NRF2 activation. LPS-stimulated NRF2-/- Bone Marrow-derived Macrophages (BMM) treated with I3B, showed higher levels of pro-inflammatory cytokine production relative to non-treated BMM. To define the upstream pathways responsible for this NRF2-depedent response, we examined GPCR-mediated signaling and found that I3B engages a Gq-coupled receptor to induce PKC{delta} phosphorylation, and subsequent NRF2 phosphorylation. Our results suggest I3B signals through a surface-receptor in a NRF2-dependent manner to reduce inflammation in murine macrophages. TeaserA cell-impermeant indole conjugate inhibits inflammatory signaling in macrophages through an NRF2-dependent mechanism.

cell biology↗

bioRxiv2022

A metabolically engineered bacterium controls autoimmunity by remodeling the pro-inflammatory microenvironment

Immunotherapy has led to impressive advances in the treatment of autoimmune and pro-inflammatory disorders; yet, its clinical outcomes remain limited by a variety of factors including the pro-inflammatory microenvironment (IME). Discovering effective immunomodulatory agents, and the mechanisms by which they control disease, will lead to innovative strategies for enhancing the effectiveness of current immunotherapeutic approaches. We have metabolically engineered an attenuated bacterial strain (i.e., Brucella melitensis 16M {Delta}vjbR, Bm{Delta}vjbR) to produce indole, a tryptophan metabolite that controls the fate and function of regulatory T cells (Tregs). We demonstrated that treatment with this strain polarized M2 macrophages (M{varphi}) which produced anti-inflammatory cytokines (e.g., IL-10) and promoted Treg function; moreover, when combined with adoptive cell transfer (ACT) of Tregs, a single treatment with our engineered bacterial strain dramatically reduced the incidence and score of autoimmune arthritis and decreased joint damage. These findings show how a metabolically engineered bacterium can constitute a powerful vehicle for improving the efficacy of immunotherapy, defeating autoimmunity and reducing inflammation by remodeling the IME and augmenting Treg function.

immunology↗

bioRxiv2019

Environmental chemical diethylhexyl phthalate alters intestinal microbiota community structure and metabolite profile in mice

Exposure to environmental chemicals during windows of development is a potentially contributing factor in gut microbiota dysbiosis, and linked to chronic diseases and developmental disorders. We used a community-level model of microbiota metabolism to investigate the effects of diethylhexyl phthalate (DEHP), a ubiquitous plasticizer implicated in neurodevelopmental disorders, on the composition and metabolite outputs of gut microbiota in young mice. Administration of DEHP by oral gavage increased the abundance of Lachnoclostridum, while decreasing Akkermansia, Odoribacter, and Clostridium sensu stricto. Addition of DEHP to in vitro cultured cecal microbiota increased the abundance of Alistipes, Paenibacillus, and Lachnoclostridium. Untargeted metabolomics showed that DEHP broadly altered the metabolite profile in the culture. Notably, DEHP enhanced the production of p-cresol, while inhibiting butyrate synthesis. Metabolic model-guided correlation analysis indicated that the likely sources of p-cresol are Clostridium species. Our results suggest that DEHP can directly modify the microbiota to affect production of bacterial metabolites linked with neurodevelopmental disorders.\n\nImportanceSeveral previous studies have pointed to environmental chemical exposure during windows of development as a contributing factor in neurodevelopmental disorders, and correlated these disorders with microbiota dysbiosis, little is known about how the chemicals specifically alter the microbiota to interfere with development. The findings reported in this paper unambiguously establish that a pollutant linked with neurodevelopmental disorders can directly modify the microbiota to promote the production of a potentially toxic metabolite (p-cresol) that has also been correlated with neurodevelopmental disorders. Further, we use a novel modeling strategy to identify the responsible enzymes and bacterial sources of this metabolite. To the best of our knowledge, the present study is the first to characterize the functional consequence of phthalate exposure on a developed microbiota. Our results suggest that specific bacterial pathways could be developed as diagnostic and therapeutic targets against health risks posed by ingestion of environmental chemicals.

microbiology↗