scholarly journals Neuronal, stromal, and T-regulatory cell crosstalk in murine skeletal muscle

2020 ◽  
Vol 117 (10) ◽  
pp. 5402-5408 ◽  
Author(s):  
Kathy Wang ◽  
Omar K. Yaghi ◽  
Raul German Spallanzani ◽  
Xin Chen ◽  
David Zemmour ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Immune Cell ◽  
Treg Cells ◽  
T Regulatory Cell ◽  
Calcitonin Gene ◽  
Genes Encoding ◽  
Large Fiber ◽  
Murine Skeletal Muscle ◽  
Related Proteins ◽  
Cell Crosstalk

A distinct population of Foxp3+CD4+ regulatory T (Treg) cells promotes repair of acutely or chronically injured skeletal muscle. The accumulation of these cells depends critically on interleukin (IL)-33 produced by local mesenchymal stromal cells (mSCs). An intriguing physical association among muscle nerves, IL-33+ mSCs, and Tregs has been reported, and invites a deeper exploration of this cell triumvirate. Here we evidence a striking proximity between IL-33+ muscle mSCs and both large-fiber nerve bundles and small-fiber sensory neurons; report that muscle mSCs transcribe an array of genes encoding neuropeptides, neuropeptide receptors, and other nerve-related proteins; define muscle mSC subtypes that express both IL-33 and the receptor for the calcitonin-gene–related peptide (CGRP); and demonstrate that up- or down-tuning of CGRP signals augments or diminishes, respectively, IL-33 production by muscle mSCs and later accumulation of muscle Tregs. Indeed, a single injection of CGRP induced much of the genetic program elicited in mSCs early after acute skeletal muscle injury. These findings highlight neural/stromal/immune-cell crosstalk in tissue repair, suggesting future therapeutic approaches.

scholarly journals Inducible Defense Mechanism against Nitric Oxide in Candida albicans

2004 ◽  
Vol 3 (3) ◽  
pp. 715-723 ◽  
Author(s):  
Breanna D. Ullmann ◽  
Hadley Myers ◽  
Wiriya Chiranand ◽  
Anna L. Lazzell ◽  
Qiang Zhao ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Candida Albicans ◽  
Defense Mechanism ◽  
Immune Cell ◽  
Opportunistic Pathogen ◽  
Mrna Levels ◽  
Genes Encoding ◽  
Nitrogen Radicals ◽  
Related Proteins ◽  
Type Strains

ABSTRACT The yeast Candida albicans is an opportunistic pathogen that threatens patients with compromised immune systems. Immune cell defenses against C. albicans are complex but typically involve the production of reactive oxygen species and nitrogen radicals such as nitric oxide (NO) that damage the yeast or inhibit its growth. Whether Candida defends itself against NO and the molecules responsible for this defense have yet to be determined. The defense against NO in various bacteria and the yeast Saccharomyces cerevisiae involves an NO-scavenging flavohemoglobin. The C. albicans genome contains three genes encoding flavohemoglobin-related proteins, CaYHB1, CaYHB4, and CaYHB5. To assess their roles in NO metabolism, we constructed strains lacking each of these genes and demonstrated that just one, CaYHB1, is responsible for NO consumption and detoxification. In C. albicans, NO metabolic activity and CaYHB1 mRNA levels are rapidly induced by NO and NO-generating agents. Loss of CaYHB1 increases the sensitivity of C. albicans to NO-mediated growth inhibition. In mice, infections with Candida strains lacking CaYHB1 still resulted in lethality, but virulence was decreased compared to that in wild-type strains. Thus, C. albicans possesses a rapid, specific, and highly inducible NO defense mechanism involving one of three putative flavohemoglobin genes.

scholarly journals Evaluation of the effect of T regulatory cell depletion and donor BCG vaccination on Mycobacterium tuberculosis H37Ra infection using an in vitro model of human PBMC infection

2020 ◽  
Vol 78 (9) ◽  
Author(s):  
Sudha Bhavanam ◽  
Gina R Rayat ◽  
Monika Keelan ◽  
Dennis Kunimoto ◽  
Steven J Drews
Keyword(s):  
Mycobacterium Tuberculosis ◽  
In Vitro Model ◽  
Mononuclear Cells ◽  
Immune Cell ◽  
Treg Cells ◽  
T Regulatory Cell ◽  
Bcg Vaccination ◽  
Vitro Model ◽  
The Impact

Abstract This study evaluated the effect of T regulatory cells (Treg cells) and the impact of BCG vaccination history of donors using an in vitro model of Mycobacterium tuberculosis H37Ra infection of peripheral blood mononuclear cells (PBMCs). PBMCs from donors with or without prior BCG vaccination were depleted of Treg cells (PBMCs-Tregs) or not depleted with Treg cells (PBMCs + Tregs) were infected up to 8 days with Mtb H37Ra. Cell aggregates were smaller in PBMCs-Tregs compared to PBMCs + Tregs at day 8 post-infection. Mtb CFUs were higher in the PBMCs-Tregs compared to PBMCs + Tregs at days 3, 5 and 8. The levels of IL-17, IFN-γ (at days 3 and 5), and TNF-α and IL-6 (at day 3) were lower in PBMCs-Tregs compared to PBMCs + Tregs. In contrast, the levels of IL-10 and IL-4 cytokines were higher at day 3 in PBMCs-Tregs compared to PBMCs + Tregs. BCG vaccination status of donors had no impact on the mycobacterial culture, level of cytokines and immune cell populations. This study shows that depletion of Tregs in human PBMCs infected with Mtb H37Ra in vitro leads to a shift from a Th1 to a Th2 cytokine rich environment that supports the survival of Mtb in this model.

scholarly journals Neither Primary nor Memory Immunity to Mycobacterium tuberculosis Infection Is Compromised in Mice with Chronic Enteric Helminth Infection

2015 ◽  
Vol 83 (3) ◽  
pp. 1217-1223 ◽  
Author(s):  
Wasiulla Rafi ◽  
Kamlesh Bhatt ◽  
William C. Gause ◽  
Padmini Salgame
Keyword(s):  
Mycobacterium Tuberculosis ◽  
T Regulatory Cells ◽  
Helminth Infection ◽  
Treg Cells ◽  
Helminth Species ◽  
Nippostrongylus Brasiliensis ◽  
T Regulatory Cell ◽  
Chronic Infections ◽  
Mycobacterium Tuberculosis Infection ◽  
Content Type

Previously we had reported thatNippostrongylus brasiliensis, a helminth with a lung migratory phase, affected host resistance againstMycobacterium tuberculosisinfection through the induction of alternatively activated (M2) macrophages. Several helminth species do not have an obligatory lung migratory phase but establish chronic infections in the host that include potent immune downregulatory effects, in part mediated through induction of a FoxP3+T regulatory cell (Treg) response. Treg cells exhibit duality in their functions in host defense againstM. tuberculosisinfection since their depletion leads to enhanced priming of T cells in the lymph nodes and attendant improved control ofM. tuberculosisinfection, while their presence in the lung granuloma protects against excessive inflammation.Heligmosomoides polygyrusis a strictly murine enteric nematode that induces a strong FoxP3 Treg response in the host. Therefore, in this study we investigated whether host immunity toM. tuberculosisinfection would be modulated in mice with chronicH. polygyrusinfection. We report that neither primary nor memory immunity conferred byMycobacterium bovisBCG vaccination was affected in mice with chronic enteric helminth infection, despite a systemic increase in FoxP3+T regulatory cells. The findings indicate that anti-M. tuberculosisimmunity is not similarly affected by all helminth species and highlight the need to consider this inequality in human coinfection studies.

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