Colwyn A. Headley

Background: Smoking and family history are major risk factors for abdominal aortic aneurysm (AAA). Smoking and nicotine are modulators of DNA methylation, capable of causing heritable epigenetic alterations. Nicotine infusion and e-cigarette (e-cig) vaping augment murine AAA. We investigated the effects of murine maternal e-cig vaping on offspring experimental AAA, and impacts on transgenerational DNA methylation and accessibility. Methods: We performed perinatal e-cig nicotine vaping in two strains of adult female mice (ApoE-/- and C57BL/6J). Mice were mated to control males, and treated through gestation. A parallel group were instead sacrificed after treatment, for DNA analysis. Offspring were aged to adulthood, and AAAs were then induced by elastase (C57BL/6J) or angiotensin-II infusion (ApoE-/-), and ultrasound-tracked for 4 weeks. In a second cohort, parental and offspring aortic tissue and blood DNA underwent RRBS and ATAC-seq analysis respectively. Offspring abdominal aortic anatomy was examined, and stiffness was assessed with ex vivo arterial myography. Results: Maternal e-cig exposure increased offspring AAA growth in both models and genders. AAA incidence was increased in ApoE-/- males, and observed effects were overall more pronounced in males. Maternal vape exposure altered aortic DNA methylation and blood DNA accessibility in mothers and offspring, with differential sites in numerous genes identified, including AAA-related genes and pathways. Pathways were enriched for transcription factors, inflammation/immune-related genes, and angiogenesis genes, with similar changes identified in exposed mothers. Male offspring displayed more differential genes. Significant changes were located in genes known to harbor AAA risk loci in humans, and overlapped with published epigenetic alterations in human smokers. Differences also occurred in offspring aortic structure and stiffness. Conclusions: Maternal e-cig nicotine exposure augments AAA growth in multiple models across generations. These effects are accompanied by broad epigenetic DNA reprogramming of key AAA modulator genes and pathways.

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.

Many successful researchers in the biomedical sciences have benefitted from mentors and networks earlier in their career. However, early-career researchers from minoritized and underrepresented groups do not have the same access to potential mentors and networks as many of their peers. In this article we describe how ‘cold emails’ and social media platforms – notably Twitter/X and LinkedIn – can be used to build virtual networks, and stress the need to invest in maintaining networks once they have been established.

Tuberculosis (TB), caused by the bacterium Mycobacterium tuberculosis ( M.tb ), remains a significant health concern worldwide, especially in populations with weakened or compromised immune systems, such as the elderly. Proper adaptive immune function, particularly a CD4 ⁺ T cell response, is central to host immunity against M.tb . Chronic infections, such as M.tb , as well as aging promote T cell exhaustion and senescence, which can impair immune control and promote progression to TB disease. Mitochondrial dysfunction contributes to T cell dysfunction, both in aging and chronic infections and diseases. Mitochondrial perturbations can disrupt cellular metabolism, enhance oxidative stress, and impair T-cell signaling and effector functions. This study examined the impact of mitochondrial transplantation (mito-transfer) on CD4 ⁺ T cell differentiation and function using aged mouse models and human CD4 ⁺ T cells from elderly individuals. Our study revealed that mito-transfer in naïve CD4 ⁺ T cells promoted the generation of protective effector and memory CD4 ⁺ T cells during M.tb infection in mice. Further, mito-transfer enhanced the function of elderly human T cells by increasing their mitochondrial mass and modulating cytokine production, which in turn reduced exhaustion and senescence cell markers. Our results suggest that mito-transfer could be a novel strategy to reestablish aged CD4 ⁺ T cell function, potentially improving immune responses in the elderly and chronic TB patients, with a broader implication for other diseases where mitochondrial dysfunction is linked to T cell exhaustion and senescence.

Mitochondrial dysfunction alters cellular metabolism, increases tissue oxidative stress, and may be principal to the dysregulated signaling and function of CD4⁺ T lymphocytes in the elderly. In this proof of principle study, it is investigated whether the transfer of functional mitochondria into CD4⁺ T cells that are isolated from old mice (aged CD4⁺ T cells), can abrogate aging‐associated mitochondrial dysfunction, and improve the aged CD4⁺ T cell functionality. The results show that the delivery of exogenous mitochondria to aged non‐activated CD4⁺ T cells led to significant mitochondrial proteome alterations highlighted by improved aerobic metabolism and decreased cellular mitoROS. Additionally, mito‐transferred aged CD4⁺ T cells showed improvements in activation‐induced TCR‐signaling kinetics displaying markers of activation (CD25), increased IL‐2 production, enhanced proliferation ex vivo. Importantly, immune deficient mouse models (RAG‐KO) showed that adoptive transfer of mito‐transferred naive aged CD4⁺ T cells, protected recipient mice from influenza A and Mycobacterium tuberculosis infections. These findings support mitochondria as targets of therapeutic intervention in aging.

Abdominal aortic aneurysm (AAA) is a common disease with substantial heritability. In this study, we performed a genome-wide association meta-analysis from 14 discovery cohorts and uncovered 141 independent associations, including 97 previously unreported loci. A polygenic risk score derived from meta-analysis explained AAA risk beyond clinical risk factors. Genes at AAA risk loci indicate involvement of lipid metabolism, vascular development and remodeling, extracellular matrix dysregulation and inflammation as key mechanisms in AAA pathogenesis. These genes also indicate overlap between the development of AAA and other monogenic aortopathies, particularly via transforming growth factor β signaling. Motivated by the strong evidence for the role of lipid metabolism in AAA, we used Mendelian randomization to establish the central role of nonhigh-density lipoprotein cholesterol in AAA and identified the opportunity for repurposing of proprotein convertase, subtilisin/kexin-type 9 (PCSK9) inhibitors. This was supported by a study demonstrating that PCSK9 loss of function prevented the development of AAA in a preclinical mouse model.

Mechanisms to shorten the duration of tuberculosis (TB) treatment include new drug formulations or schedules and the development of host-directed therapies (HDTs) that better enable the host immune system to eliminate Mycobacterium tuberculosis. Previous studies have shown that pyrazinamide, a first-line antibiotic, can also modulate immune function, making it an attractive target for combinatorial HDT/antibiotic therapy, with the goal to accelerate clearance of M. tuberculosis. In this study, we assessed the value of anti–IL-10R1 as an HDT along with pyrazinamide and show that short-term anti–IL-10R1 blockade during pyrazinamide treatment enhanced the antimycobacterial efficacy of pyrazinamide, resulting in faster clearance of M. tuberculosis in mice. Furthermore, 45 d of pyrazinamide treatment in a functionally IL-10–deficient environment resulted in sterilizing clearance of M. tuberculosis. Our data suggest that short-term IL-10 blockade with standard TB drugs has the potential to improve clinical outcome by reducing the treatment duration.

Mycobacterium bovis bacillus Calmette–Guérin (BCG) immunization still remains the best vaccination strategy available to control the development of active tuberculosis. Protection afforded by BCG vaccination gradually wanes over time and although booster strategies have promise, they remain under development. An alternative approach is to improve BCG efficacy through host-directed therapy. Building upon prior knowledge that blockade of IL-10R1 during early Mycobacterium tuberculosis infection improves and extends control of M. tuberculosis infection in mice, we employed a combined anti–IL-10R1/BCG vaccine strategy. An s.c. single vaccination of BCG/anti–IL10-R1 increased the numbers of CD4⁺ and CD8⁺ central memory T cells and reduced Th1 and Th17 cytokine levels in the lung for up to 7 wk postvaccination. Subsequent M. tuberculosis challenge in mice showed both an early (4 wk) and sustained long-term (47 wk) control of infection, which was associated with increased survival. In contrast, protection of BCG/saline-vaccinated mice waned 8 wk after M. tuberculosis infection. Our findings demonstrate that a single and simultaneous vaccination with BCG/anti–IL10-R1 sustains long-term protection, identifying a promising approach to enhance and extend the current BCG-mediated protection against TB. Key Points A single dose of BCG/anti–IL-10R1 generates long-term BCG-specific memory immunity. A single dose of BCG/anti–IL-10R1 reverses waning protective efficacy of BCG.

Mitochondrial dysfunction alters cellular metabolism, increases tissue oxidative stress, and may be principal to the dysregulated signaling and function of CD4 ⁺ T lymphocytes in the elderly. In this proof of principle study, we investigated whether the transfer of functional mitochondria into CD4 ⁺ T cells that were isolated from old mice (aged CD4 ⁺ T cells), could abrogate aging-associated mitochondrial dysfunction, and improve the aged CD4 ⁺ T cell functionality. Our results show that the delivery of exogenous mitochondria to aged non-activated CD4 ⁺ T cells led to significant mitochondrial proteome alterations highlighted by improved aerobic metabolism and decreased cellular mitoROS. Additionally, mito-transferred aged CD4 ⁺ T cells showed improvements in activation-induced TCR-signaling kinetics displaying markers of activation (CD25), increased IL-2 production, enhanced proliferation ex vivo . Importantly, immune deficient mouse models (RAG-KO) showed that adoptive transfer of mito-transferred naive aged CD4 ⁺ T cells, protected recipient mice from influenza A and Mycobacterium tuberculosis infections. These findings support mitochondria as targets of therapeutic intervention in aging.

Vaccine and antiviral development against SARS-CoV-2 infection or COVID-19 disease would benefit from validated small animal models. Here, we show that transgenic mice expressing human angiotensin-converting enzyme 2 (hACE2) by the human cytokeratin 18 promoter (K18 hACE2) represent a susceptible rodent model. K18 hACE2 transgenic mice succumbed to SARS-CoV-2 infection by day 6, with virus detected in lung airway epithelium and brain. K18 ACE2 transgenic mice produced a modest TH1/2/17 cytokine storm in the lung and spleen that peaked by day 2, and an extended chemokine storm that was detected in both lungs and brain. This chemokine storm was also detected in the brain at day 6. K18 hACE2 transgenic mice are, therefore, highly susceptible to SARS-CoV-2 infection and represent a suitable animal model for the study of viral pathogenesis, and for identification and characterization of vaccines (prophylactic) and antivirals (therapeutics) for SARS-CoV-2 infection and associated severe COVID-19 disease.