On the selectivity of neuronal NOS inhibitors

Pigott, Beatrice M.; Bartus, Katalin; Garthwaite, John

doi:10.1111/bph.12016

Cited by 23 publications

(22 citation statements)

References 72 publications

(128 reference statements)

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“…LM-MP from ampicillin, control and withdrawal groups were washed in standard Krebs solution and then incubated for 1 hour at 37 °C with or without Nomega-Nitro-L-arginine (L-NNA), a specific inhibitor for nNOS 25–27 . At the end of the incubation period, the supernatants were collected and used for NO quantification.…”

Section: Methodsmentioning

confidence: 99%

Intestinal Bacteria Maintain Adult Enteric Nervous System and Nitrergic Neurons via Toll-like Receptor 2-induced Neurogenesis in Mice

Yarandi

Kulkarni

Saha

et al. 2020

Preprint

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Background & Aims: The enteric nervous system (ENS) exists in close proximity to luminal bacteria. Intestinal microbes regulate ENS development, but little is known about their effects on adult enteric neurons. We investigated whether intestinal bacteria or their products affect the adult ENS via toll like receptors (TLRs) in mice. Methods:We performed studies with conventional C57/BL6, germ-free C57/BL6, Nestin-creER T2 :tdTomato, Nestin-GFP, and ChAT-cre:tdTomato. Mice were given drinking water with ampicillin or without (controls). Germ-free mice were given drinking water with TLR2 agonist or without (controls). Some mice were given a blocking antibody against TLR2 or a TLR4 inhibitor.We performed whole-gut transit, bead latency, and geometric center studies. Feces were collected and analyzed by 16S rRNA gene sequencing. Longitudinal muscle myenteric plexus (LMMP) tissues were collected, analyzed by immunohistochemistry, and levels of nitric oxide were measured. Cells were isolated from colonic LMMP of Nestin-creER T2 :tdTomato mice and incubated with agonists of TLR2 (receptor for Gram-positive bacteria), TLR4 (receptor for Gramnegative bacteria), or distilled water (control) andd analyzed by flow cytometry.Results: Stool from mice given ampicillin had altered composition of gut microbiota with reduced abundance of Gram-positive bacteria and increased abundance of Gram-negative bacteria, compared with mice given only water. Mice given ampicillin had reduced colon motility compared with mice given only water, and their colonic LMMP had reduced numbers of nitrergic neurons, reduced nNOS production, and reduced colonic neurogenesis. Numbers of colonic myenteric neurons increased after mice were switched from ampicillin to plain water, with increased markers of neurogenesis. Nestin-positive ENPCs expressed TLR2 and TLR4. In cells isolated from the colonic LMMP, incubation with the TLR2 agonist increased the percentage of neurons originating from ENPCs to approximately 10%, compared to approximately 0.01% in cells incubated with the TLR4 agonist or distilled water. Mice given an antibody against TLR2 had prolonged whole-gut transit times; their colonic LMMP had reduced total neurons and a smaller proportion of nitrergic neurons per ganglion, and reduced markers of neurogenesis compared with mice given saline. Colonic LMMP of mice given the TLR4 inhibitor did not have reduced markers of neurogenesis. Colonic LMMP of germ-free mice given TLR2 agonist had increased neuronal numbers compared with control germ-free mice. Conclusions:In the adult mouse colon, TLR2 promotes colonic neurogenesis, regulated by intestinal bacteria. Our findings indicate that colonic microbiota help maintain the adult ENS via a specific signaling pathway. Pharmacologic and probiotic approaches directed towards specific TLR2 signaling processes might be developed for treatment of colonic motility disorders related to use of antibiotics or other factors.

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Section: Methodsmentioning

confidence: 99%

Intestinal Bacteria Maintain Adult Enteric Nervous System and Nitrergic Neurons via Toll-like Receptor 2-induced Neurogenesis in Mice

Yarandi

Kulkarni

Saha

et al. 2020

Preprint

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“…8 A), where it is primarily located in inhibitory interneurones (Bredt et al, 1990 ; Wood et al, 2011 ). As NO synthase inhibitors able to distinguish between the two isoforms experimentally in intact cells and tissues are still lacking (Pigott et al, 2013 ), cGMP immunostaining was applied to cerebellar slices from wild-type mice and mice deficient in eNOS. On exposure to BAY 41-2272, the staining was indistinguishable, with cGMP being found in oligodendrocytes as well as in Bergmann glia and other presumed astrocytes ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Nitric oxide targets oligodendrocytes and promotes their morphological differentiation

Garthwaite

Hampden-Smith

Wilson

et al. 2014

Glia

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In the central nervous system, nitric oxide (NO) transmits signals from one neurone to another, or from neurones to astrocytes or blood vessels, but the possibility of oligodendrocytes being physiological NO targets has been largely ignored. By exploiting immunocytochemistry for cGMP, the second messenger generated on activation of NO receptors, oligodendrocytes were found to respond to both exogenous and endogenous NO in cerebellar slices from rats aged 8 days to adulthood. Atrial natriuretic peptide, which acts on membrane-associated guanylyl cyclase-coupled receptors, also raised oligodendrocyte cGMP in cerebellar slices. The main endogenous source of NO accessing oligodendrocytes appeared to be the neuronal NO synthase isoform, which was active even under basal conditions and in a manner that was independent of glutamate receptors. Oligodendrocytes in brainstem slices were also shown to be potential NO targets. In contrast, in the optic nerve, oligodendrocyte cGMP was raised by natriuretic peptides but not NO. When cultures of cerebral cortex were continuously exposed to low NO concentrations (estimated as 40–90 pM), oligodendrocytes responded with a striking increase in arborization. This stimulation of oligodendrocyte growth could be replicated by low concentrations of 8-bromo-cGMP (maximum effect at 1 µM). It is concluded that oligodendrocytes are probably widespread targets for physiological NO (or natriuretic peptide) signals, with the resulting rise in cGMP serving to enhance their growth and maturation. NO might help coordinate the myelination of axons to the ongoing level of neuronal activity during development and could potentially contribute to adaptive changes in myelination in the adult.

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“…NO is the main metabolite from arginine and NOS/NO signal modulates downstream proteins via specific posttranslational modifications (Pigott et al 2013). Dysfunction of NOS/NO (i.e., altered expression, location, coupling, activity, etc.)…”

Section: Discussionmentioning

confidence: 99%

Preinduction of heat shock protein 70 protects mice against post-infection irritable bowel syndrome via NF-κB and NOS/NO signaling pathways

et al. 2015

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This study aimed to investigate the protective effects of preinduction of heat shock protein 70 (HSP70) on Trichinella spiralis infection-induced post-infectious irritable bowel syndrome (PI-IBS) in mice. Trichinella spiralis infection significantly reduced HSP70 abundance, ileal villus height and crypt depth, expression of tight junctions, serum lysine and arginine concentrations, and ileal SCL7A6 and SCL7A7 mRNA levels, induced inflammatory response, and activated NF-κB signaling pathway. Meanwhile, the heat treatment upregulated HSP70 expression, and then reversed intestinal dysfunction and inflammatory response. Preinduction of HSP70 enhanced serum arginine and intestinal SCL7A7 expression and inhibited NF-κB activation compared with PI-IBS model. Treatment with pyrrolidine dithiocarbamate (PDTC, an NF-κB inhibitor) and N-nitro-L-arginine methyl ester hydrochloride (L-NAME, a nitric oxide synthase inhibitor, NOS) further demonstrated that preinduction of HSP70 might inhibit NF-κB and activated NOS/nitric oxide (NO) signaling pathways. In conclusion, preinduction of HSP70 by heat treatment may confer beneficial effects on Trichinella spiralis infection-induced PI-IBS in mice, and the protective effect of HSP70 may be associated with inhibition of NF-κB and stimulation of NOS/NO signaling pathways.

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On the selectivity of neuronal NOS inhibitors

Cited by 23 publications

References 72 publications

Intestinal Bacteria Maintain Adult Enteric Nervous System and Nitrergic Neurons via Toll-like Receptor 2-induced Neurogenesis in Mice

Intestinal Bacteria Maintain Adult Enteric Nervous System and Nitrergic Neurons via Toll-like Receptor 2-induced Neurogenesis in Mice

Nitric oxide targets oligodendrocytes and promotes their morphological differentiation

Preinduction of heat shock protein 70 protects mice against post-infection irritable bowel syndrome via NF-κB and NOS/NO signaling pathways

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