Almost 140 years after its discovery, tuberculosis remains the leading infectious cause of death globally. For half a century, patients with drug-sensitive and drug-resistant tuberculosis have undergone long, arduous, and complex treatment processes with several antimicrobials that primarily function through direct bactericidal activity. Long-term utilization of these antimicrobials has been well-characterized and associated with numerous toxic side-effects. With the prevalence of drug-resistant strains on the rise and new therapies for tuberculosis urgently required, a more thorough understanding of these antimicrobials is a necessity. In order to progress from the “one size fits all” treatment approach, understanding how these antimicrobials affect mitochondrial function and bioenergetics may provide further insight into how these drugs affect the overall functions of host immune cells during tuberculosis infection. Such insights may help to inform future studies, instigate discussion, and help toward establishing personalized approaches to using such antimicrobials which could help to pave the way for more tailored treatment regimens. While recent research has highlighted the important role mitochondria and bioenergetics play in infected host cells, only a small number of studies have examined how these antimicrobials affect mitochondrial function and immunometabolic processes within these immune cells. This short review highlights how these antimicrobials affect key elements of mitochondrial function, leading to further discussion on how they affect bioenergetic processes, such as glycolysis and oxidative phosphorylation, and how antimicrobial-induced alterations in these processes can be linked to downstream changes in inflammation, autophagy, and altered bactericidal activity.

For over 50 years, patients with drug-sensitive and drug-resistant tuberculosis have undergone long, arduous, and complex treatment processes with several antimicrobials. With the prevalence of drug-resistant strains on the rise and new therapies for tuberculosis urgently required, we assessed whether manipulating iron levels in macrophages infected with mycobacteria offered some insight into improving current antimicrobials that are used to treat drug-resistant tuberculosis. We investigated if the iron chelator, desferrioxamine, can support the function of human macrophages treated with an array of second-line antimicrobials, including moxifloxacin, bedaquiline, amikacin, clofazimine, linezolid and cycloserine. Primary human monocyte-derived macrophages were infected with Bacillus Calmette-Guérin (BCG), which is pyrazinamide-resistant, and concomitantly treated for 5 days with desferrioxamine in combination with each one of the second-line tuberculosis antimicrobials. Our data indicate that desferrioxamine used as an adjunctive treatment to bedaquiline significantly reduced the bacterial load in human macrophages infected with BCG. Our findings also reveal a link between enhanced bactericidal activity and increases in specific cytokines, as the addition of desferrioxamine increased levels of IFN-γ, IL-6, and IL-1β in BCG-infected human monocyte-derived macrophages (hMDMs) treated with bedaquiline. These results provide insight, and an in vitro proof-of-concept, that iron chelators may prove an effective adjunctive therapy in combination with current tuberculosis antimicrobials.

Tuberculosis (TB) remains a global health challenge. Patients with drug-sensitive and drug-resistant TB undergo long, arduous, and complex treatment regimens, often involving multiple antimicrobials. While these drugs were initially implemented based on their bactericidal effects, some studies show that TB antimicrobials can also directly affect cells of the immune system, altering their immune function. As use of these antimicrobials has been the mainstay of TB therapy for over fifty years now, it is more important than ever to understand how these antimicrobials affect key pathways of the immune system. One such central pathway, which underpins the immune response to a variety of infections, is immunometabolism, namely glycolysis and oxidative phosphorylation (OXPHOS). We hypothesise that in addition to their direct bactericidal effect on Mycobacterium tuberculosis (Mtb), current TB antimicrobials can modulate immunometabolic profiles and alter mitochondrial function in primary human macrophages. Human monocyte-derived macrophages (hMDMs) were differentiated from PBMCs isolated from healthy blood donors, and treated with four first-line and six second-line TB antimicrobials three hours post stimulation with either iH37Rv-Mtb or lipopolysaccharide (LPS). 24 h post stimulation, baseline metabolism and mitochondrial function were determined using the Seahorse Extracellular Flux Analyser. The effect of these antimicrobials on cytokine and chemokine production was also assayed using Meso Scale Discovery Multi-Array technology. We show that some of the TB antimicrobials tested can significantly alter OXPHOS and glycolysis in uninfected, iH37Rv-Mtb, and LPS-stimulated hMDMs. We also demonstrate how these antimicrobial-induced immunometabolic effects are linked with alterations in mitochondrial function. Our results show that TB antimicrobials, specifically clofazimine, can modify host immunometabolism and mitochondrial function. Moreover, clofazimine significantly increased the production of IL-6 in human macrophages that were stimulated with iH37Rv-Mtb. This provides further insight into the use of some of these TB antimicrobials as potential host-directed therapies in patients with early and active disease, which could help to inform TB treatment strategies in the future.

Introduction: Novel therapeutic options are urgently required to improve outcomes and survival for patients with lung squamous cell carcinoma (LUSC). In particular, understanding the unique histological features that define LUSC is essential to improving lung cancer mortality. Many pre-clinical models fail to accurately represent intratumour heterogeneity and recapitulate the tumour microenvironment. This is partly responsible for the poor translation of clinical findings to approved therapies. Our objective was to investigate whether patient-derived organoids, replicate the histological morphological, and structural features of keratinizing LUSC, a poor prognostic subtype of lung cancer. Methods: Organoid cultures were established and maintained from two patients presenting with keratinizing lung squamous cell carcinomas. Immunofluorescent staining of individual organoids and confocal microscopy was performed to confirm expression of tumour markers. Whole organoid domes were fixed, and immunofluorescent staining and imaging was performed to investigate the structural features of the organoid cultures. Findings were compared with histopathological features of the original tumour tissue. Results: Patient-derived organoids expressed tumour markers specific to the squamous cell carcinoma subtype of non-small cell lung cancer, which were confirmed to be expressed in the parent tissue. Within organoid cultures, keratin pearl structures spontaneously developed, matching the keratinizing pattern demonstrated by hematoxylin and eosin staining of the original tumour. Conclusions: Patient-derived organoids have the capability to replicate key histological features of their parent tumour. This high degree of fidelity makes these 3D models an important and valuable tool for understanding complex tumour biology and as a platform for preclinical drug testing to advance novel therapies into the clinic.

Increasing evidence suggests extracellular vesicles (EVs) are key components of liquid biopsies to aid cancer diagnosis and treatment selection, if their collection can be translated to clinical settings. Size exclusion chromatography (SEC) is relatively simple, fast, and cost-effective, but its potential for "real-world" EVs collection for cancer diagnoses is unknown. Here we aimed to critically evaluate SEC using clinically-relevant plasma volumes and across a range of common cancer types that are frequently diagnosed too late. EVs were collected, using qEV70 or qEV35 SEC columns, from duplicate aliquots of n = 43 plasma samples procured at diagnosis with lung, ovarian, or gastric cancers and characterised on multiple parameters, seeking correlations with patients clinicopathological information. To investigate potential diagnostic relevance, EVs were collected in the same way from n = 10 plasma samples from healthy donors. We found that SEC has many attributes indicating that it is translatable to real-world clinical utility. With both SEC types, relatively large quantities of EVs were successfully collected from small plasma volumes for all three cancer types. No significant differences existed between qEV70 and qEV35 particle sizes, structure, and EVs markers. EVs in qEV35 isolates versus qEV70 isolates had reduced purity and/or increased protein corona, but both isolates revealed clinical correlations. Importantly, depending on the cancer type(s), results suggested that the EVs isolates at the time of cancer diagnosis may inform on lymph node-positivity and advanced stage, and may be prognostic for shorter time to disease progression. Furthermore, analysis of plasma CD63+ EVs and CD81+ EVs appears to have diagnostic relevance, due to their typically significantly greater quantities in cancer types compared to healthy controls. Altogether, SEC shows promise as a potential approach for clinical EVs collection as liquid biopsies and correlations between plasma EVs quantities with a range of clinicopathological characteristics suggests this would be worthwhile.