Publications

UNLABELLED: We previously reported that live, but not dead, virulent Mycobacterium tuberculosis (Mtb) H37Rv bacilli induce cell death in human lung fibroblast cell lines, MRC-5, MRC-9, and TIG-1. Here, using two distinct Mtb strains from two different lineages (HN878 lineage 2 and H37Rv lineage 4), we confirmed cell death at day 2 after infection with a device that measures cell growth/cytotoxicity in real time (Maestro-Z [AXION]). Mtb bacilli uptake by the fibroblast was confirmed with a transmission electron microscope on day 2. Expressions of inflammatory cytokines and interleukin (IL)-1β, IL-6, and IL-8 were observed when exposed to live, but not dead bacteria. The cell death of fibroblasts induced by both Mtb strains tested was prevented by caspase-1/4 and NLRP3 inflammasome inhibitors, but not by caspase-3 and caspase-9 inhibitors. Therefore, we classified the fibroblast cell death by Mtb infection as pyroptosis. To investigate the biological and pathological relevance of fibroblast cell death by Mtb infection, we performed dual RNA-Seq analysis on Mtb within fibroblasts and Mtb-infected fibroblasts at day 2. In Mtb bacilli tcrR, secE2, ahpD, and mazF8 genes were highly induced during infection. These genes play roles in survival in a hypoxic environment, production of a calcium-binding protein-inducing cytokine, and regulation of transcription in a toxin-antitoxin system. The gene expressions of IL-1β, IL-6, and IL-8, caspase-4, and NLRP3, but not of caspase-3 and caspase-9, were augmented in Mtb bacilli-infected fibroblasts. Taken together, our study suggests that Mtb bacilli attempt to survive in lung fibroblasts and that pyroptosis of the host fibroblasts activates the immune system against the infection.

IMPORTANCE: The role of "non-classical immune cells," that is, fibroblasts, epithelial cells, adipocytes, etc., except for the "classical immune cells," that is, macrophages and lymphoid cells, is not well known in the infection of Mtb bacilli. We have previously found that live, but not dead, Mtb bacilli induce cell death in human lung fibroblasts, except in human macrophages and monocytes. The present study reveals that fibroblasts ingest Mtb bacilli the same as macrophages and that in vivo Mtb bacilli within fibroblasts attempt to survive in the host cells, and pyroptosis, including the production of inflammatory cytokines, is induced in the Mtb-infected fibroblasts. Our results suggest that pyroptosis of the host fibroblasts activates the immune system against the infection.

BACKGROUND: Nigeria bears a high burden of infectious diseases, with the second-highest human immunodeficiency virus (HIV) prevalence globally and the largest tuberculosis (TB) burden in Africa. The country faces significant challenges from armed conflicts, insurgency, kidnapping and banditry, which severely strain its healthcare system, particularly for people living with HIV (PLHIV). This study hypothesizes that PLHIV in conflict-affected regions of Nigeria experience a higher burden of TB than those in non-conflict areas.

METHODS: This cross-sectional household survey utilised a two-stage cluster sampling design to examine HIV/TB co-infection and associated behaviours in Nigeria, based on data from the 2018 Nigeria HIV/ acquired immune deficiency syndrome (AIDS) Indicator and Impact Survey. The sample included adults aged 15 to 64 in the selected households. We mapped the distribution of HIV/TB co-infection across the country and calculated its prevalence, stratified by conflict and non-conflict zones. Adjusted odds ratios (AOR) and 95% confidence intervals (CIs) from survey-weighted logistic regression models were used to assess the likelihood of being diagnosed with TB disease among PLHIV.

RESULTS: We analysed weighted data from 1,319,719 PLHIV across Nigeria, with 200,201(15.2%) residing in conflict zones and 1,119,518 (84.8%) in non-conflict zones. Overall, the prevalence of HIV/TB co-infection was 40.4% (52,118), with PLHIV residents of conflict zones exhibiting a significantly higher prevalence (59%, 14,976) compared to those from non-conflict zones (36%, 37,413). After adjusting for confounders, PLHIV in conflict zones were more than four times more likely to acquire TB than those from non-conflict zones (AOR: 4.21, 95% CI: 1.72-10.5, p = 0.002).

CONCLUSIONS: Conflicts amplify the risk of TB among PLHIV in Nigeria, highlighting an urgent need for targeted interventions to strengthen healthcare access in these regions. The efforts are essential in achieving the goals of reducing TB prevalence by 50% and TB mortality by 75% by 2025, as well as meeting the 95-95-95 targets to control HIV by 2030.

The Coronavirus Immunotherapeutic Consortium (CoVIC) conducted side-by-side comparisons of over 400 anti-SARS-CoV-2 spike therapeutic antibody candidates contributed by large and small companies as well as academic groups on multiple continents. Nine reference labs analyzed antibody features, including in vivo protection in a mouse model of infection, spike protein affinity, high-resolution epitope binning, ACE-2 binding blockage, structures, and neutralization of pseudovirus and authentic virus infection, to build a publicly accessible dataset in the database CoVIC-DB. High-throughput, high-resolution binning of CoVIC antibodies defines a broad and predictive landscape of antibody epitopes on the SARS-CoV-2 spike protein and identifies features associated with durable potency against multiple SARS-CoV-2 variants of concern and high in vivo efficacy. Results of the CoVIC studies provide a guide for selecting effective and durable antibody therapeutics and for immunogen design as well as providing a framework for rapid response to future viral disease outbreaks.

In recent decades, drug resistant (DR) strains of Mycobacterium tuberculosis (M.tb), the cause of tuberculosis (TB), have emerged that threaten public health. Although M.tb's complex and protective cell envelope has been widely studied, little is known about how levels of peripheral lipids change in relation to drug resistance. In this study, we examined levels of cell envelope lipids [phthiocerol dimycocerosates (PDIMs)], glycolipids [phosphatidyl-myo-inositol mannosides (PIMs)], and PIMs associated lipoglycans [lipomannan (LM); mannose-capped lipoarabinomannan (ManLAM)] of 22 M.tb strains that ranged in drug resistance profile. We show that the PDIMs:PIMs ratio increases as drug resistance increases, and provide evidence of PDIM isomers only present in the DR-M.tb strains studied. Overall, the LM and ManLAM levels did not differ between drug resistance categories, but ManLAM surface exposure increased with drug resistance. Infection of human macrophages revealed that DR-M.tb strains have decreased association compared to drug susceptible (DS) strains, and that the pre-XDR M.tb strain with the largest PDIMs:PIMs ratio had decreased uptake, but increased intracellular growth at early during infection compared to the DS-M.tb strain H37Rv. These findings suggest that PDIMs may play an important role in drug resistance and that an increase in hydrophobic cell envelope lipids may influence M.tb-host interactions.

The host range of HPAIV H5N1 was recently expanded to include ruminants, particularly dairy cattle in the United States (US). Shortly after, human H5N1 infection was reported in a dairy worker in Texas following exposure to infected cattle. Herein, we rescued the cattle-origin influenza A/bovine/Texas/24-029328-02/2024(H5N1, rHPbTX) and A/Texas/37/2024(H5N1, rHPhTX) viruses, identified in dairy cattle and human, respectively, and their low pathogenic forms, rLPbTX and rLPhTX, with monobasic HA cleavage sites. Intriguingly, rHPhTX replicated more efficiently than rHPbTX in mammalian and avian cells. Still, variations in the PA and NA proteins didn't affect their antiviral susceptibility to PA and NA inhibitors. Unlike rHPbTX and rLPbTX, both rHPhTX and rLPhTX exhibited higher pathogenicity and efficient replication in infected C57BL/6J mice. The lungs of rHPhTX-infected mice produced higher inflammatory cytokines/chemokines than rHPbTX-infected mice. Our results highlight the potential risk of HPAIV H5N1 virus adaptation in human and/or dairy cattle during the current multistate/multispecies outbreak in the US.

BACKGROUND: The global setback in tuberculosis (TB) prevalence and mortality in the post-COVID-19 era has been partially attributed to pandemic-related disruptions in healthcare systems. The additional biological contribution of COVID-19 to TB is less clear. The goal of this study was to determine if there is an association between COVID-19 in the past 18 months and a new TB episode, and the role played by type 2 diabetes mellitus (DM) comorbidity in this relationship.

METHODS: A cross-sectional study was conducted among 112 new active TB patients and 373 non-TB controls, identified between June 2020 and November 2021 in communities along the Mexican border with Texas. Past COVID-19 was based on self-report or positive serology. Bivariable/multivariable analysis were used to evaluate the odds of new TB in hosts with past COVID-19 and/or DM status.

RESULTS: The odds of new TB were higher among past COVID-19 cases vs. controls, but only significant among DM patients (aOR 2.3). The odds of TB in people with DM was 2.7-fold higher among participants without past COVID-19 and increased to 7.9-fold among those with past COVID-19.

CONCLUSION: DM interacts with past COVID-19 synergistically to magnify the risk of TB. Latent TB screening and prophylactic treatment, if positive, is recommended in past COVID-19 persons with DM. Future studies are warranted with a longitudinal design and larger sample size to confirm our findings.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (M.tb), is a major global health concern, particularly affecting those with weakened immune systems, including the elderly. CD4+ T cell response is crucial for immunity against M.tb, but chronic infections and aging can lead to T cell exhaustion and senescence, worsening TB disease. Mitochondrial dysfunction, prevalent in aging and chronic diseases, disrupts cellular metabolism, increases oxidative stress, and impairs T-cell functions. This study investigates the effect of mitochondrial transplantation (mito-transfer) on CD4+ T cell differentiation and function in aged mouse models and human CD4+ T cells from elderly individuals. Mito-transfer in naïve CD4+ T cells is found to promote protective effector and memory T cell generation during M.tb infection in mice. Additionally, it improves elderly human T cell function by increasing mitochondrial mass and altering cytokine production, thereby reducing markers of exhaustion and senescence. These findings suggest mito-transfer as a novel approach to enhance aged CD4+ T cell functionality, potentially benefiting immune responses in the elderly and chronic TB patients. This has broader implications for diseases where mitochondrial dysfunction contributes to T-cell exhaustion and senescence.

With devastating health and socioeconomic impact worldwide, much work is left to understand the Coronavirus Disease 2019 (COVID-19), with emphasis in the severely affected elderly population. Here, we present a proteomics study of lung tissue obtained from aged vs. young rhesus macaques (Macaca mulatta) and olive baboons (Papio Anubis) infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Using age as a variable, we identified common proteomic profiles in the lungs of aged infected non-human primates (NHPs), including key regulators of immune function, as well as cell and tissue remodeling, and discuss the potential clinical relevance of such parameters. Further, we identified key differences in proteomic profiles between both NHP species, and compared those to what is known about SARS-CoV-2 in humans. Finally, we explored the translatability of these animal models in the context of aging and the human presentation of the COVID-19.

Mycobacterium tuberculosis (M.tb), the causative agent of tuberculosis (TB), is considered one of the top infectious killers in the world. In recent decades, drug resistant (DR) strains of M.tb have emerged that make TB even more difficult to treat and pose a threat to public health. M.tb has a complex cell envelope that provides protection to the bacterium from chemotherapeutic agents. Although M.tb cell envelope lipids have been studied for decades, very little is known about how their levels change in relation to drug resistance. In this study, we examined changes in the cell envelope lipids [namely, phthiocerol dimycocerosates (PDIMs)], glycolipids [phosphatidyl-myo-inositol mannosides (PIMs)], and the PIM associated lipoglycans [lipomannan (LM); mannose-capped lipoarabinomannan (ManLAM)] of 11 M.tb strains that range from drug susceptible (DS) to multi-drug resistant (MDR) to pre-extensively drug resistant (pre-XDR). We show that there was an increase in the PDIMs:PIMs ratio as drug resistance increases, and provide evidence of PDIM species only present in the DR-M.tb strains studied. Overall, the LM and ManLAM cell envelope levels did not differ between DS- and DR-M.tb strains, but ManLAM surface exposure proportionally increased with drug resistance. Evaluation of host-pathogen interactions revealed that DR-M.tb strains have decreased association with human macrophages compared to DS strains. The pre-XDR M.tb strain with the largest PDIMs:PIMs ratio had decreased uptake, but increased intracellular growth rate at early time points post-infection when compared to the DS-M.tb strain H37Rv. These findings suggest that PDIMs may play an important role in drug resistance and that this observed increase in hydrophobic cell envelope lipids on the DR-M.tb strains studied may influence M.tb-host interactions.