Publications by authors named "Radhakrishnan Rajesh Kumar"

Tissue-resident immune cells play important roles in local tissue homeostasis and infection control. There is no information on the functional role of lung-resident CD3-NK1.1+CD69+CD103+ cells in intranasal Bacillus Calmette-Guérin (BCG)-vaccinated and/or Mycobacterium tuberculosis (Mtb)-infected mice.

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Article Synopsis
  • - The study explores how Mycobacterium tuberculosis (Mtb) infection impacts inflammatory responses in type 2 diabetes mellitus (T2DM) mice, revealing that necroptosis significantly contributes to increased inflammation in their alveolar macrophages.
  • - Treatment with an anti-TNFR1 antibody reduced markers of necroptosis and inflammatory cytokine IL-6 production in Mtb-infected T2DM mice, indicating a potential therapeutic approach.
  • - A metabolic analysis showed that specific metabolites like 2-ketohexanoic acid increased inflammation, while pyridoxine (Vitamin B6) could reduce inflammation by altering cell death pathways in T2DM mice infected with Mtb.
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To determine the mechanisms that mediate resistance to Mycobacterium tuberculosis (M. tuberculosis) infection in household contacts (HHCs) of patients with tuberculosis (TB), we followed 452 latent TB infection-negative (LTBI-) HHCs for 2 years. Those who remained LTBI- throughout the study were identified as nonconverters.

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Article Synopsis
  • - The study tracked 839 household contacts of TB patients over 2 years to identify risk factors for developing TB, revealing that most cases were in individuals aged 15 to 30.
  • - It was found that those who progressed to TB had lower levels of the thyroid hormone thyroxine (T4) and produced less IL-1α when exposed to TB antigens, which indicates a possible immune response impairment.
  • - The research suggests that low thyroid hormone levels may increase the risk of developing active TB, particularly in young individuals, as demonstrated by experiments on mutant mice with altered thyroid hormone receptors.
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Macrophages are professional phagocytes known to play a vital role in controlling Mycobacterium tuberculosis (Mtb) infection and disease progression. Here we compare Mtb growth in mouse alveolar (AMs), peritoneal (PMs), and liver (Kupffer cells; KCs) macrophages and in bone marrow-derived monocytes (BDMs). KCs restrict Mtb growth more efficiently than all other macrophages and monocytes despite equivalent infections through enhanced autophagy.

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Diabetes is a significant risk factor for the development of active tuberculosis. In this study, we used a mouse model of type 2 diabetes mellitus (T2DM) to determine the effect of prior Bacillus Calmette-Guérin (BCG) vaccination on immune responses to Mycobacterium tuberculosis (Mtb) infection. We found that, at 6-7 months after Mtb infection, 90% of the Mtb-infected T2DM mice died, whereas only 50% of BCG-vaccinated T2DM-Mtb-infected mice died.

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Redox homeostasis is tightly controlled and regulates key cellular signaling pathways. The cell's antioxidant response provides a natural defense against oxidative stress, but excessive antioxidant generation leads to reductive stress (RS). This study elucidated how chronic RS, caused by constitutive activation of nuclear erythroid related factor-2 (caNrf2)-dependent antioxidant system, drives pathological myocardial remodeling.

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Previously, we found that pathological immune responses enhance the mortality rate of Mycobacterium tuberculosis (Mtb)-infected mice with type 2 diabetes mellitus (T2DM). In the current study, we evaluated the role of the cytokine IL-22 (known to play a protective role in bacterial infections) and type 3 innate lymphoid cells (ILC3s) in regulating inflammation and mortality in Mtb-infected T2DM mice. IL-22 levels were significantly lower in Mtb-infected T2DM mice than in nondiabetic Mtb-infected mice.

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In the current study, we used a mouse model and human blood samples to determine the effects of chronic alcohol consumption on immune responses during Mycobacterium tuberculosis (Mtb) infection. Alcohol increased the mortality of young mice but not old mice with Mtb infection. CD11b+Ly6G+ cells are the major source of IFN-α in the lungs of Mtb-infected alcohol-fed young mice, and IFN-α enhances macrophage necroptosis in the lungs.

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Article Synopsis
  • CD4+CD25+FoxP3+ Tregs play a crucial role in controlling immune responses against transplanted tissues, specifically islet allografts in this study.
  • The research reveals that Tregs lacking c-Jun N-terminal kinase 1 (JNK1) signaling are more effective at prolonging islet allograft survival in diabetic mice by surviving longer in the liver and being resistant to cell death.
  • Additionally, JNK1-deficient Tregs show increased expression of the anti-inflammatory cytokine IL-10 and the molecule LAG-3, which helps them better inhibit immune responses compared to normal Tregs.
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Background: In the current study, we determined the effects of interleukin (IL)-21 on human natural killer (NK) cells and monocyte responses during Mycobacterium tuberculosis (Mtb) infection.

Methods: We found that Mtb stimulated CD4+ and NK T cells from healthy individuals with latent tuberculosis infection (LTBI+) are major sources of IL-21. CD4+ cells from tuberculosis patients secreted less IL-21 than did CD4+ cells from healthy LTBI+ individuals.

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Background: Anomalies in myocardial structure involving myocyte growth, hypertrophy, differentiation, apoptosis, necrosis etc. affects its function and render cardiac tissue more vulnerable to the development of heart failure. Although oxidative stress has a well-established role in cardiac remodeling and dysfunction, the mechanisms linking redox state to atrial cardiomyocyte hypertrophic changes are poorly understood.

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A homologous series of 1-alkyl-(N,N-dimethylamino)pyridinium bromides, termed compounds 1-11, was synthesized and studied for antibacterial and antifungal activity. Of these, compound 8, containing a ten-carbon alkyl chain, showed maximum inhibition against all the tested bacterial strains. The highest antibacterial activity using a disc diffusion method was recorded against Mycobacterium smegmatis [zone of inhibition (ZOI): 45.

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