The Role of microRNAs and Long Non-Coding RNAs in the Regulation of the Immune Response to Mycobacterium tuberculosis Infection

Diagnostic value of lncRNAs LINC00152 and LARS2-AS1 and their regulatory roles in macrophage immune response in tuberculosis

OBJECTIVES

To determine the usefulness of LINC00152 and LARS2-AS1 as potential biomarkers for latent tuberculosis (LTB) and active tuberculosis (ATB), as well as their effect on Mycobacterium (Mtb) infection.

METHODS

The expression levels of LINC00152 and LARS2-AS1 in the health, patients with LTB and ATB were detected by qRT-PCR. The ROC curves were constructed to show their potential as biomarkers. The intracellular survival assays for Mtb and the levels of immune-related cytokines were determined to discover the effect of LINC00152 and LARS2-AS1 on Mtb infection. The relationships of miR-485-5p with LINC00152 and LARS2-AS1 were explored.

RESULTS

LINC00152 and LARS2-AS1 levels were significantly elevated in patients with ATB and LTB, and Mtb-infected macrophages. LINC00152 and LARS2-AS1 can distinguish the LTB from the health and ATB from LTB. LARS2-AS1 and LINC00152 knock-down reduced the intracellular Mtb survival and induced cellular immune response after Mtb challenge. miR-485-5p was a targeting miRNA for LINC00152 and LARS2-AS1.

CONCLUSIONS

LINC00152 and LARS2-AS1 can be considered as potential biomarkers for tuberculosis disease. LINC00152 and LARS2-AS1 have anti-Mtb effects.

Long noncoding RNA NONHSAT122636.2 attenuates myocardial inflammation and apoptosis in myocarditis

OBJECTIVE

The main pathological change of myocarditis is an inflammatory injury of cardiomyocytes. Long noncoding RNAs (lncRNAs) are closely related to inflammation, and our previous study showed that differential expression of lncRNAs is associated with myocarditis. This study aimed to investigate the impact of lncRNAs on the onset of myocarditis.

METHODS

RNA expression was measured by quantitative reverse-transcription polymerase chain reaction (RT-qPCR). Lipopolysaccharide (LPS) was used to induce inflammation in human cardiomyocytes (HCMs). The expression of inflammatory cytokines and myocardial injury markers was detected by enzyme-linked immunosorbent assay (ELISA) and RT-qPCR. Cell viability and apoptosis were measured by the cell counting kit-8 assay and flow cytometry. The binding force between lncRNA NONHSAT122636.2 and microRNA miRNA-2110 was detected using the dual-luciferase assay.

RESULTS

NONHSAT122636.2 was dynamically expressed in patients with myocarditis and negatively correlated with inflammation severity. The overexpression of NONHSAT122636.2 improved inflammatory injury in LPS-stimulated HCMs. The study observed that there was a weak binding force between NONHSAT122636.2 and miR-2110.

CONCLUSION

NONHSAT122636.2 attenuates myocardial inflammation and apoptosis in myocarditis. Additionally, its expression decreases in the peripheral blood of children suffering from myocarditis and in patients who are diagnosed for the first time showing higher diagnostic sensitivity and specificity. This decrease is negatively correlated with the degree of inflammation. Overall, the study suggests that NONHSAT122636.2 can be exploited as a potential diagnostic biomarker for pediatric myocarditis.

The role of Mycobacterium tuberculosis exosomal miRNAs in host pathogen cross-talk as diagnostic and therapeutic biomarkers

Tuberculosis (TB) is a global threat, affecting one-quarter of the world's population. The World Health Organization (WHO) reports that 6 million people die annually due to chronic illnesses, a statistic that includes TB-related deaths. This high mortality is attributed to factors such as the emergence of drug-resistant strains and the exceptional survival mechanisms of Mycobacterium tuberculosis (MTB). Recently, microRNAs (miRNAs) have garnered attention for their crucial role in TB pathogenesis, surpassing typical small RNAs (sRNA) in their ability to alter the host's immune response. For instance, miR-155, miR-125b, and miR-29a have been identified as key players in the immune response to MTB, particularly in modulating macrophages, T cells, and cytokine production. While sRNAs are restricted to within cells, exo-miRNAs are secreted from MTB-infected macrophages. These exo-miRNAs modify the function of surrounding cells to favor the bacterium, perpetuating the infection cycle. Another significant aspect is that the expression of these miRNAs affects specific genes and pathways involved in immune functions, suggesting their potential use in diagnosing TB and as therapeutic targets. This review compiles existing information on the immunomodulatory function of exosomal miRNAs from MTB, particularly focusing on disease progression and the scientific potential of this approach compared to existing diagnostic techniques. Thus, the aim of the study is to understand the role of exosomal miRNAs in TB and to explore their potential for developing novel diagnostic and therapeutic methods.

An Update on the Study of the Molecular Mechanisms Involved in Autophagy during Bacterial Pathogenesis

Autophagy is a unique catabolic process that degrades irrelevant or damaged components in eukaryotic cells to maintain homeostasis and eliminate infections from pathogenesis. Pathogenic bacteria have developed many autophagy manipulation techniques that affect host immune responses and intracellular bacterial pathogens have evolved to avoid xenophagy. However, reducing its effectiveness as an innate immune response has not yet been elucidated. Bacterial pathogens cause autophagy in infected cells as a cell-autonomous defense mechanism to eliminate the pathogen. However, harmful bacteria have learned to control autophagy and defeat host defenses. Intracellular bacteria can stimulate and control autophagy, while others inhibit it to prevent xenophagy and lysosomal breakdown. This review evaluates the putative functions for xenophagy in regulating bacterial infection, emphasizing that successful pathogens have evolved strategies to disrupt or exploit this defense, reducing its efficiency in innate immunity. Instead, animal models show that autophagy-associated proteins influence bacterial pathogenicity outside of xenophagy. We also examine the consequences of the complex interaction between autophagy and bacterial pathogens in light of current efforts to modify autophagy and develop host-directed therapeutics to fight bacterial infections. Therefore, effective pathogens have evolved to subvert or exploit xenophagy, although autophagy-associated proteins can influence bacterial pathogenicity outside of xenophagy. Finally, this review implies how the complex interaction between autophagy and bacterial pathogens affects host-directed therapy for bacterial pathogenesis.

Whole-transcriptome sequencing of phagocytes reveals a ceRNA network contributing to natural resistance to tuberculosis infection

Tuberculosis (TB) is a major fatal infectious disease globally, exhibiting high morbidity rates and impacting public health and other socio-economic factors. However, some individuals are resistant to TB infection and are referred to as "Resisters". Resisters remain uninfected even after exposure to high load of Mycobacterium tuberculosis (Mtb). To delineate this further, this study aimed to investigate the factors and mechanisms influencing the Mtb resistance phenotype. We assayed the phagocytic capacity of peripheral blood mononuclear cells (PBMCs) collected from Resisters, patients with latent TB infection (LTBI), and patients with active TB (ATB), following infection with fluorescent Mycobacterium bovis Bacillus Calmette-Guérin (BCG). Phagocytosis was stronger in PBMCs from ATB patients, and comparable in LTBI patients and Resisters. Subsequently, phagocytes were isolated and subjected to whole transcriptome sequencing and small RNA sequencing to analyze transcriptional expression profiles and identify potential targets associated with the resistance phenotype. The results revealed that a total of 277 mRNAs, 589 long non-coding RNAs, 523 circular RNAs, and 35 microRNAs were differentially expressed in Resisters and LTBI patients. Further, the endogenous competitive RNA (ceRNA) network was constructed from differentially expressed genes after screening. Bioinformatics, statistical analysis, and quantitative real-time polymerase chain reaction were used for the identification and validation of potential crucial targets in the ceRNA network. As a result, we obtained a ceRNA network that contributes to the resistance phenotype. TCONS_00034796-F3, ENST00000629441-DDX43, hsa-ATAD3A_0003-CYP17A1, and XR_932996.2-CERS1 may be crucial association pairs for resistance to TB infection. Overall, this study demonstrated that the phagocytic capacity of PBMCs was not a determinant of the resistance phenotype and that some non-coding RNAs could be involved in the natural resistance to TB infection through a ceRNA mechanism.

Roles of HIF-1α signaling in Mycobacterium tuberculosis infection: New targets for anti-TB therapeutics?

Tuberculosis (TB), a deadly infectious disease induced by Mycobacterium tuberculosis (Mtb), continues to be a global public health issue that kill millions of patents every year. Despite significant efforts have been paid to identify effective TB treatments, the emergence of drug-resistant strains of the disease and the presence of comorbidities in TB patients urges us to explore the detailed mechanisms involved in TB immunity and develop more effective innovative anti-TB strategies. HIF-1α, a protein involved in regulating cellular immune responses during TB infection, has been highlighted as a promising target for the development of novel strategies for TB treatment due to its critical roles in anti-TB host immunity. This review provides a summary of current research progress on the roles of HIF-1α in TB infection, highlighting its importance in regulating the host immune response upon Mtb infection and summarizing the influences and mechanisms of HIF-1α on anti-TB immunological responses of host cells. This review also discusses the various challenges associated with developing HIF-1α as a target for anti-TB therapies, including ensuring specificity and avoiding off-target effects on normal cell function, determining the regulation and expression of HIF-1α in TB patients, and developing drugs that can inhibit HIF-1α. More deep understanding of the molecular mechanisms involved in HIF-1α signaling, its impact on TB host status, and systematic animal testing and clinical trials may benefit the optimization of HIF-1α as a novel therapeutic target for TB.

Construction of ceRNA regulatory networks for active pulmonary tuberculosis

Delayed diagnosis in patients with pulmonary tuberculosis (PTB) often leads to serious public health problems. High throughput sequencing was used to determine the expression levels of lncRNAs, mRNAs, and miRNAs in the lesions and adjacent health lung tissues of patients with PTB. Their differential expression profiles between the two groups were compared, and 146 DElncRs, 447 DEmRs, and 29 DEmiRs were obtained between lesions and adjacent health tissues in patients with PTB. Enrichment analysis for mRNAs showed that they were mainly involved in Th1, Th2, and Th17 cell differentiation. The lncRNAs, mRNAs with target relationship with miRNAs were predicted respectively, and correlation analysis was performed. The ceRNA regulatory network was obtained by comparing with the differentially expressed transcripts (DElncRs, DEmRs, DEmiRs), then 2 lncRNAs mediated ceRNA networks were established. The expression of genes within the network was verified by quantitative real-time PCR (qRT-PCR). Flow cytometric analysis revealed that the proportion of Th1 cells and Th17 cells was lower in PTB than in controls, while the proportion of Th2 cells increased. Our results provide rich transcriptome data for a deeper investigation of PTB. The ceRNA regulatory network we obtained may be instructive for the diagnosis and treatment of PTB.

Crucial role of lncRNA NONHSAG037054.2 and GABPA, and their related functional networks, in ankylosing spondylitis

Long non-coding RNAs (lncRNAs) have been previously researched in ankylosing spondylitis (AS). Nevertheless, there are few studies of lncRNAs and mRNAs associated with the pathogenesis of AS. Differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEmRNAs) between AS and normal samples were assessed using the R limma package. DOSE packages and 'clusterProfiler' were exploited for gene enrichment analysis. The functional association of proteins and protein interactions was assessed using the STRING database. To investigate the important genes and subnetworks in the protein-protein interaction network, the MCODE plug-in in the Cytoscape software was utilized. The gene mRNA was examined via reverse transcription-quantitative PCR. In total, 152 DEmRNAs and 204 DElncRNAs were observed between normal and AS samples. A total of 68 candidate genes related to DElncRNA were identified. These candidate genes were enriched in 30 cellular component terms, 22 molecular functions, 83 biological processes, 9 Kyoto Encyclopedia of Genes and Genomes, and 36 disease ontology pathways. NONHSAG037054.2 was the most related lncRNA to genes, and GABPA was the most connected gene to lncRNA in AS. The NCBI/GenBank accession number of the lncRNA NONHSAG037054.2 was not found because it is not included in NCBI. The information of lncRNA NONHSAG037054.2 can be found at the website (http://www.noncode.org/show_gene.php?id=NONHSAG037054 and https://www.genecards.org/cgi-bin/carddisp.pl?gene=ACAP2-IT1). In total, 13 microRNAs (miRNAs) and 46 miRNAs associated with NONHSAG037054.2 and GABPA, respectively, were found. A total of 173 RNA-binding protein genes were associated with both NONHSAG037054.2 and GABPA. In addition, GABPA was downregulated in AS samples, suggesting it may have diagnostic value in AS. In conclusion, NONHSAG037054.2 and GABPA are associated with AS. GABPA was downregulated in AS, and it could serve as a novel diagnostic factor for AS.

Non-coding RNAs in disease: from mechanisms to therapeutics

Non-coding RNAs (ncRNAs) are a heterogeneous group of transcripts that, by definition, are not translated into proteins. Since their discovery, ncRNAs have emerged as important regulators of multiple biological functions across a range of cell types and tissues, and their dysregulation has been implicated in disease. Notably, much research has focused on the link between microRNAs (miRNAs) and human cancers, although other ncRNAs, such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), are also emerging as relevant contributors to human disease. In this Review, we summarize our current understanding of the roles of miRNAs, lncRNAs and circRNAs in cancer and other major human diseases, notably cardiovascular, neurological and infectious diseases. Further, we discuss the potential use of ncRNAs as biomarkers of disease and as therapeutic targets.

LncRNA POU6F2-AS2 contributes to malignant phenotypes and paclitaxel resistance by promoting SKP2 expression in stomach adenocarcinoma

This study aimed to investigate the role and mechanism of POU6F2-AS2 in the development of gastric cancer. POU6F2-AS2 expression was considerably higher in clinical stomach adenocarcinoma (STAD) tissues and gastric cancer cell lines (MKN-28 and MGC-803) than in neighbouring normal tissues and gastric mucosa epithelial cells (GES-1). POU6F2-AS2 overexpression resulted in a low overall survival probability, progression-free survival probability and post progression survival probability, as well as increased cell viability, migration and invasion of gastric cancer cells, thereby inhibiting apoptosis. Based on RNA pull-down, cycloheximide and MG132 incubation experiments, POU6F2-AS2 promoted SKP2 by stabilizing NONO expression. In addition, in vivo silencing of POU6F2-AS2 in gastric cancer cells can inhibit tumour progression and produce a synergistic antitumour effect when combined with paclitaxel. POU6F2-AS2 is overexpressed in STAD, which is attributed to a bad prognosis. In vitro and in vivo experiments have confirmed that the POU6F2-AS2/NONO/SKP2 axis promotes STAD progression, and that the silencing of POU6F2-AS2 plays a synergistic antitumour effect when combined with paclitaxel. Therefore, POU6F2-AS2 may be potentially developed as a target to inhibit STAD and reduce chemoresistance.

Diagnostic performance of microRNA-29a in active pulmonary tuberculosis: a systematic review and meta-analysis

BACKGROUND

In recent years, more and more studies have shown that microRNA-29a (miRNA-29a) can be used as a potential biomarker for active tuberculosis, but the results of these studies are not consistent.

OBJECTIVE

To comprehensively evaluate the value of miRNA-29a in the diagnosis of active tuberculosis by meta-analysis.

METHODS

The databases of CNKI, WanFang, PubMed, The Cochrane Library, Web of Science and EMBASE were searched for relevant studies. Studies were screened strictly according to inclusion and exclusion criteria. QUADAS-2 scale was used to evaluate the quality of the included studies. Data were extracted and analyzed by Meta-DiSc 1.4 and Stata 16.0 software.

RESULTS

13 articles were included, including a total of 1598 subjects, including 872 active tuberculosis patients and 726 controls. The combined sensitivity and specificity of miRNA-29a in the diagnosis of active tuberculosis were 78 % and 76 %, respectively, and the area under the overall summary receiver operating characteristic curve was 0.8564.

CONCLUSION

miRNA-29a can be used as a biomarker for the diagnosis of active tuberculosis.

SNHG15 promotes gallbladder cancer progression by enhancing the autophagy of tumor cell under nutrition stress

Gallbladder cancer (GBC) is a major malignant carcinoma of the biliary tract with extremely poor prognosis. Currently, there is no useful therapy strategies for GBC treatment, indicating the unmet mechanism researches for GBC. In this study, our data showed that SNHG15 expression significantly up-regulated and its high expression associated with poor overall survival of patients suffer from GBC. Functional experiments showed that SNHG15 depletion delayed the proliferation and enhanced the apoptosis of GBC tumor cells under the nutrition stress condition, which further confirmed in the subcutaneous xenograft model and liver metastasis model. Mechanistically, SNHG15 could interact with AMPK and facilitate the phosphorylation of AMPK to Tuberous sclerosis complex TSC2, resulting in mTOR suppression and autophagy enhancement, and finally, conferring the GBC cell sustain proliferation under nutrition stress. Taken together, our findings revealed that SNHG15 promotes GBC tumor progression by enhancing the autophagy under poor nutrition tumor microenvironment, which could be a promising targets for GBC.

Advances of Long Non-Coding RNAs as Potential Biomarkers for Tuberculosis: New Hope for Diagnosis?

Tuberculosis (TB), one of the top ten causes of death globally induced by the infection of Mycobacterium tuberculosis (Mtb), remains a grave public health issue worldwide. With almost one-third of the world's population getting infected by Mtb, between 5% and 10% of these infected individuals are predicted to develop active TB disease, which would not only result in severe tissue damage and necrosis, but also pose serious threats to human life. However, the exact molecular mechanisms underlying the pathogenesis and immunology of TB remain unclear, which significantly restricts the effective control of TB epidemics. Despite significant advances in current detection technologies and treatments for TB, there are still no appropriate solutions that are suitable for simultaneous, early, rapid, and accurate screening of TB. Various cellular events can perturb the development and progression of TB, which are always associated with several specific molecular signaling events controlled by dysregulated gene expression patterns. Long non-coding RNAs (lncRNAs), a kind of non-coding RNA (ncRNA) with a transcript of more than 200 nucleotides in length in eukaryotic cells, have been found to regulate the expression of protein-coding genes that are involved in some critical signaling events, such as inflammatory, pathological, and immunological responses. Increasing evidence has claimed that lncRNAs might directly influence the susceptibility to TB, as well as the development and progression of TB. Therefore, lncRNAs have been widely expected to serve as promising molecular biomarkers and therapeutic targets for TB. In this review, we summarized the functions of lncRNAs and their regulatory roles in the development and progression of TB. More importantly, we widely discussed the potential of lncRNAs to act as TB biomarkers, which would offer new possibilities in novel diagnostic strategy exploration and benefit the control of the TB epidemic.

Macrophages in immunoregulation and therapeutics

Macrophages exist in various tissues, several body cavities, and around mucosal surfaces and are a vital part of the innate immune system for host defense against many pathogens and cancers. Macrophages possess binary M1/M2 macrophage polarization settings, which perform a central role in an array of immune tasks via intrinsic signal cascades and, therefore, must be precisely regulated. Many crucial questions about macrophage signaling and immune modulation are yet to be uncovered. In addition, the clinical importance of tumor-associated macrophages is becoming more widely recognized as significant progress has been made in understanding their biology. Moreover, they are an integral part of the tumor microenvironment, playing a part in the regulation of a wide variety of processes including angiogenesis, extracellular matrix transformation, cancer cell proliferation, metastasis, immunosuppression, and resistance to chemotherapeutic and checkpoint blockade immunotherapies. Herein, we discuss immune regulation in macrophage polarization and signaling, mechanical stresses and modulation, metabolic signaling pathways, mitochondrial and transcriptional, and epigenetic regulation. Furthermore, we have broadly extended the understanding of macrophages in extracellular traps and the essential roles of autophagy and aging in regulating macrophage functions. Moreover, we discussed recent advances in macrophages-mediated immune regulation of autoimmune diseases and tumorigenesis. Lastly, we discussed targeted macrophage therapy to portray prospective targets for therapeutic strategies in health and diseases.

Integrated analysis of mRNA and microRNA expression pattern reveals differential transcriptome signatures in RIPK2 over-expressing chicken macrophages infected with avian pathogenic E. coli

1. As RIPK2 (receptor interacting serine/threonine kinase 2) has been shown to to alleviate excessive inflammatory responses, the following study conducted a systematic and in-depth analysis of the mRNA-seq and miRNA-seq data from chicken macrophages with/without over-expression of RIPK2 (oeRIPK2) combined with/without avian pathogenic E. coli (APEC) infection to identify the miRNA-mRNA interaction network and potential signalling pathways involved.2. A total of 9,201 differentially expressed (DE) mRNAs and 300 DE miRNA were identified in both oeRIPK2+APEC vs. APEC and oeRIPK2 vs. the wild-type (WT). Moreover, 4,269 instances of co-expression between miRNAs and mRNAs were seen involving 1,652 DE mRNAs and 164 DE miRNAs.3. Functional analysis of the DE mRNAs in the miRNA-mRNA interaction network showed that 223 biological processes and five KEGG pathways were significantly enriched in the two comparisons. In total, 128 pairs of miRNA-mRNA interactions were involved in the identified MAPK signalling pathway and focal adhesion immune related pathways.4. Significantly, these screened miRNAs (gga-miR-222b-5p and gga-miR-214) and their target genes were highly correlated with APEC infection and RIPK2. These recognised key genes, miRNA and the overall miRNA-mRNA regulatory network, enables better understanding of the molecular mechanism of host response to APEC infection, especially related to RIPK2.

Identification of N6-methylandenosine-related lncRNA for tuberculosis diagnosis in person living with human immunodeficiency virus

Development of a robust diagnostic test for patients co-infected with human immunodeficiency virus and tuberculosis (HIV/TB) is urgently needed. We believe N6-methyladenosine (m6A)- related long non-coding RNA (lncRNAs) from the host blood could be utilized to diagnose patients co-infected with HIV/TB. In this study, differentially expressed analysis, correlation analysis, univariate logistic regression, and logistic regression with least absolute shrinkage and selection operator (LASSO) were performed in RNA-Seq dataset containing of 14 HIV/TB co-infected subjects and 11 HIV mono-infected subjects. In total, five m6A related-lncRNAs with powerful diagnostic significance for HIV/TB co-infection were identified. We then built a deep learning model based on the five m6A related-lncRNAs for accurately discriminating the HIV/TB co-infected patients from HIV mono-infected patients with an accuracy of 92.0%, a sensitivity of 92.9%, a specificity of 90.9%, and an area under the receiver operating characteristic (ROC) curve (AUC) of 0.935. Moreover, the diagnostic performance was validated in an external cohort containing 15 HIV/TB co-infected subjects and 16 HIV mono-infected subjects of whole blood. Overall, the findings showed that deep learning model based on five m6A-related lncRNAs had a worthy diagnostic performance for HIV/TB co-infection, and these diagnostic lncRNAs associated with m6A regulator genes could play a potential role in the pathogenesis of HIV/TB co-infection.

Identification of Circular RNA Profiles in the Liver of Diet-Induced Obese Mice and Construction of the ceRNA Network

Obesity is a major risk factor for cardiovascular, cerebrovascular, metabolic, and respiratory diseases, and it has become an important social health problem affecting the health of the population. Obesity is affected by both genetic and environmental factors. In this study, we constructed a diet-induced obese C57BL/6J mouse model and performed deep RNA sequencing (RNA-seq) on liner-depleted RNA extracted from the liver tissues of the mice to explore the underlying mechanisms of obesity. A total of 7469 circular RNAs (circRNAs) were detected, and 21 were differentially expressed (DE) in the high-fat diet (HFD) and low-fat diet (LFD) groups. We then constructed a comprehensive circRNA-associated competing endogenous RNA (ceRNA) network. Bioinformatic analysis indicated that DE circRNAs associated with lipid metabolic-related pathways may act as miRNA sponges to modulate target gene expression. CircRNA1709 and circRNA4842 may serve as new candidates to regulate the expression of PTEN. This study provides systematic circRNA-associated ceRNA profiling in HFD mouse liver, and the results can aid early diagnosis and the selection of treatment targets for obesity in the future.

MicroRNAs as Biomarkers of Active Pulmonary TB Course

The spread of drug-resistant forms of TB dictates the need for surgical treatment in the complex of anti-tuberculosis measures in Russia. Most often, surgical intervention is performed in the case of pulmonary tuberculoma or fibrotic cavitary tuberculosis (FCT). This study is devoted to the search for biomarkers that characterize the course of disease in surgical TB patients. It is assumed that such biomarkers will help the surgeon decide on the timing of the planned operation. A number of serum microRNAs, potential regulators of inflammation and fibrosis in TB, selected on the basis of PCR-Array analysis, were considered as biomarkers. Quantitative real time polymerase chain reaction and receiver operating curves (ROC) were used to verify Array data and to estimate the ability of microRNAs (miRNAs) to discriminate between healthy controls, tuberculoma patients, and FCT patients. The study showed that miR-155, miR-191 and miR-223 were differentially expressed in serum of tuberculoma with “decay” and tuberculoma without “decay” patients. Another combination (miR-26a, miR-191, miR-222 and miR-320) forms a set to differentiate between tuberculoma with “decay” and FCT. Patients with tuberculoma without “decay” diagnosis differ from those with FCT in serum expression of miR-26a, miR-155, miR-191, miR-222 and miR-223. Further investigations are required to evaluate these sets on a larger population so as to set cut-off values that could be applied in laboratory diagnosis.

The roles of long noncoding RNA-mediated macrophage polarization in respiratory diseases

Macrophages play an essential role in maintaining the normal function of the innate and adaptive immune responses during host defence. Macrophages acquire diverse functional phenotypes in response to various microenvironmental stimuli, and are mainly classified into classically activated macrophages (M1) and alternatively activated macrophages (M2). Macrophage polarization participates in the inflammatory, fibrotic, and oncogenic processes of diverse respiratory diseases by changing phenotype and function. In recent decades, with the advent of broad-range profiling methods such as microarrays and next-generation sequencing, the discovery of RNA transcripts that do not encode proteins termed "noncoding RNAs (ncRNAs)" has become more easily accessible. As one major member of the regulatory ncRNA family, long noncoding RNAs (lncRNAs, transcripts >200 nucleotides) participate in multiple pathophysiological processes, including cell proliferation, differentiation, and apoptosis, and vary with different stimulants and cell types. Emerging evidence suggests that lncRNAs account for the regulation of macrophage polarization and subsequent effects on respiratory diseases. In this review, we summarize the current published literature from the PubMed database concerning lncRNAs relevant to macrophage polarization and the underlying molecular mechanisms during the occurrence and development of respiratory diseases. These differentially expressed lncRNAs are expected to be biomarkers and targets for the therapeutic regulation of macrophage polarization during disease development.

Functions of exosomal non-coding RNAs to the infection with Mycobacterium tuberculosis

Tuberculosis (TB) is a major infectious disease induced by Mycobacterium tuberculosis (M. tb) which causes the world's dominant fatal bacterial contagious disease. Increasing studies have indicated that exosomes may be a novel option for the diagnosis and treatment of TB. Exosomes are nanovesicles (30-150 nm) containing lipids, proteins and non-coding RNAs (ncRNAs) released from various cells, and can transfer their cargos and communicate between cells. Furthermore, exosomal ncRNAs exhibit diagnosis potential in bacterial infections, including TB. Additionally, differential exosomal ncRNAs regulate the physiological and pathological functions of M. tb-infected cells and act as diagnostic markers for TB. This current review explored the potential biological roles and the diagnostic application prospects of exosomal ncRNAs, and included recent information on their pathogenic and therapeutic functions in TB.

The diagnostic value of combined detection of microRNA-155, TNF-α and IL-37 for active pulmonary tuberculosis in the elderly

OBJECTIVE

To identify a panel of potential biomarkers consisting of microRNA-155 (miR-155), tumor necrosis factor-alpha (TNF-α), interleukin-37 (IL-37) for the diagnosis of active pulmonary tuberculosis (PTB) infection in elderly patients.

METHODS

The serum expression of miR-155 and TNF-α in patients was measured by RT-qPCR, and the serum IL-37 level was determined by ELISA. The correlation between their expression and the features of active PTB patients was also analyzed. The AUCs of miR-155, TNF-α and IL-37 in diagnosing active PTB was calculated according to the ROC curves. The sensitivity, specificity and Youden's index of the three biomarkers alone or in combination for the active PTB diagnosis in the elderly were assessed.

RESULTS

miR-155, TNF-α, and IL-37 were overexpressed in the sera of elderly patients with active PTB. miR-155, TNF-α and IL-37 serum levels were enhanced in the elderly patients with pulmonary and extrapulmonary TB relative to those with PTB only, and in patients with active TB infection in both lungs compared to those with unilateral lung infection. The AUCs of miR-155, TNF-α and IL-37 for the diagnosis of active PTB were 0.7920, 0.8734 and 0.7398, respectively. The combination of these three improved the sensitivity of the diagnosis (84.78%).

CONCLUSION

miR-155, TNF-α and IL-37 were overexpressed in elderly patients with active PTB. The combined detection of serum miR-155/TNF-α/IL-37 expression has potential to serve as a diagnostic tool for active PTB in the elderly.

Different modalities of host cell death and their impact on Mycobacterium tuberculosis infection

Mycobacterium tuberculosis (Mtb) is the pathogen that causes tuberculosis (TB), a leading infectious disease of humans worldwide. One of the main histopathological hallmarks of TB is the formation of granulomas comprised of elaborately organized aggregates of immune cells containing the pathogen. Dissemination of Mtb from infected cells in the granulomas due to host and mycobacterial factors induces multiple cell death modalities in infected cells. Based on molecular mechanism, morphological characteristics, and signal dependency, there are two main categories of cell death: programmed and nonprogrammed. Programmed cell death (PCD), such as apoptosis and autophagy, is associated with a protective response to Mtb by keeping the bacteria encased within dead macrophages that can be readily phagocytosed by arriving in uninfected or neighboring cells. In contrast, non-PCD necrotic cell death favors the pathogen, resulting in bacterial release into the extracellular environment. Multiple types of cell death in the PCD category, including pyroptosis, necroptosis, ferroptosis, ETosis, parthanatos, and PANoptosis, may be involved in Mtb infection. Since PCD pathways are essential for host immunity to Mtb, therapeutic compounds targeting cell death signaling pathways have been experimentally tested for TB treatment. This review summarizes different modalities of Mtb-mediated host cell deaths, the molecular mechanisms underpinning host cell death during Mtb infection, and its potential implications for host immunity. In addition, targeting host cell death pathways as potential therapeutic and preventive approaches against Mtb infection is also discussed.

Resistance and Susceptibility Immune Factors at Play during Mycobacterium tuberculosis Infection of Macrophages

Tuberculosis (TB), caused by infection with Mycobacterium tuberculosis (M.tb), is responsible for >1.5 million deaths worldwide annually. Innate immune cells, especially macrophages, are the first to encounter M.tb, and their response dictates the course of infection. During infection, macrophages exert a variety of immune factors involved in either controlling or promoting the growth of M.tb. Research on this topic has been performed in both in vitro and in vivo animal models with discrepant results in some cases based on the model of study. Herein, we review macrophage resistance and susceptibility immune factors, focusing primarily on recent advances in the field. We include macrophage cellular pathways, bioeffector proteins and molecules, cytokines and chemokines, associated microbiological factors and bacterial strains, and host genetic factors in innate immune genes. Recent advances in mechanisms underlying macrophage resistance and susceptibility factors will aid in the successful development of host-directed therapeutics, a topic emphasized throughout this review.

Non-coding RNAs: Key players in T cell exhaustion

T cell exhaustion caused by continuous antigen stimulation in chronic viral infections and the tumor microenvironment is a major barrier to successful elimination of viruses and tumor cells. Although immune checkpoint inhibitors should reverse T cell exhaustion, shortcomings, such as off-target effects and single targets, limit their application. Therefore, it is important to identify molecular targets in effector T cells that simultaneously regulate the expression of multiple immune checkpoints. Over the past few years, non-coding RNAs, including microRNAs and long non-coding RNAs, have been shown to participate in the immune response against viral infections and tumors. In this review, we focus on the roles and underlying mechanisms of microRNAs and long non-coding RNAs in the regulation of T cell exhaustion during chronic viral infections and tumorigenesis. We hope that this review will stimulate research to provide more precise and effective immunotherapies against viral infections and tumors.

Host-Directed Targeting of LincRNA-MIR99AHG Suppresses Intracellular Growth of Mycobacterium tuberculosis

Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) kills 1.6 million people worldwide every year, and there is an urgent need for targeting host-pathogen interactions as a strategy to reduce mycobacterial resistance to current antimicrobials. Noncoding RNAs are emerging as important regulators of numerous biological processes and avenues for exploitation in host-directed therapeutics. Although long noncoding RNAs (lncRNAs) are abundantly expressed in immune cells, their functional role in gene regulation and bacterial infections remains understudied. In this study, we identify an immunoregulatory long intergenic noncoding RNA, lincRNA-MIR99AHG, which is upregulated in mouse and human macrophages upon IL-4/IL-13 stimulation and downregulated after clinical Mtb HN878 strain infection and in peripheral blood mononuclear cells from active TB patients. To evaluate the functional role of lincRNA-MIR99AHG, we used antisense locked nucleic acid (LNA) GapmeR-mediated antisense oligonucleotide (ASO) lncRNA knockdown experiments. Knockdown of lincRNA-MIR99AHG with ASOs significantly reduced intracellular Mtb growth in mouse and human macrophages and reduced pro-inflammatory cytokine production. In addition, in vivo treatment of mice with MIR99AHG ASOs reduced the mycobacterial burden in the lung and spleen. Furthermore, in macrophages, lincRNA-MIR99AHG is translocated to the nucleus and interacts with high affinity to hnRNPA2/B1 following IL-4/IL-13 stimulation and Mtb HN878 infection. Together, these findings identify lincRNA-MIR99AHG as a positive regulator of inflammation and macrophage polarization to promote Mtb growth and a possible target for adjunctive host-directed therapy against TB.

Identification and validation of a T-cell-related MIR600HG/hsa-mir-21-5p competing endogenous RNA network in tuberculosis activation based on integrated bioinformatics approaches

Background: T cells play critical roles in the progression of tuberculosis (TB); however, knowledge regarding these molecular mechanisms remains inadequate. This study constructed a critical ceRNA network was constructed to identify the potentially important role of TB activation via T-cell regulation.

Methods: We performed integrated bioinformatics analysis in a randomly selected training set from the GSE37250 dataset. After estimating the abundance of 18 types of T cells using ImmuCellAI, critical T-cell subsets were determined by their diagnostic accuracy in distinguishing active from latent TB. We then identified the critical genes associated with T-cell subsets in TB activation through co-expression analysis and PPI network prediction. Then, the ceRNA network was constructed based on RNA complementarity detection on the DIANA-LncBase and mirDIP platform. The gene biomarkers included in the ceRNA network were lncRNA, miRNA, and targeting mRNA. We then applied an elastic net regression model to develop a diagnostic classifier to assess the significance of the gene biomarkers in clinical applications. Internal and external validations were performed to assess the repeatability and generalizability.

Results: We identified CD4⁺ T, Tr1, nTreg, iTreg, and Tfh as T cells critical for TB activation. A ceRNA network mediated by the MIR600HG/hsa-mir-21-5p axis was constructed, in which the significant gene cluster regulated the critical T subsets in TB activation. MIR600HG, hsa-mir-21-5p, and five targeting mRNAs (BCL11B, ETS1, EPHA4, KLF12, and KMT2A) were identified as gene biomarkers. The elastic net diagnostic classifier accurately distinguished active TB from latent. The validation analysis confirmed that our findings had high generalizability in different host background cases.

Conclusion: The findings of this study provided novel insight into the underlying mechanisms of TB activation and identifying prospective biomarkers for clinical applications.

p50-associated Cyclooxygenase-2 Extragenic RNA (PACER) and Long Non-coding RNA 13 (LNC13) as potential biomarkers for monitoring tuberculosis treatment

Gaps in early and accurate diagnosis, effective drug control, and treatment monitoring are hindering the global eradication effort of tuberculosis. This infectious disease has become the deadliest worldwide before the outbreak of Covid-19. The search for new molecular biomarkers of tuberculosis will help to reverse this trend. Long non-coding RNAs (lncRNAs) have emerged as important regulators of the host immune response to infection, hence their link with the etiology and diagnosis of tuberculosis has attracted some attention from the research community. However, very little is known about their potential for the monitoring of tuberculosis treatment. This study aimed at assessing the potential of two lncRNAs: p50-associated Cyclooxygenase-2 Extragenic RNA (PACER) and Long Non-coding RNA 13 (LNC13) in the monitoring of tuberculosis treatment. This was a cross-sectional study carried out in Douala, Cameroon from December 2020 to August 2021. A quantitative real-time polymerase chain reaction followed by Cq analysis using the Livak method were performed to measure the relative expression levels of PACER and LNC13 in whole blood of healthy controls, patients with active pulmonary tuberculosis at the initiation of treatment, after two, five, and six months into treatment. Receiver Operating Characteristic curves analysis was used to assess the ability of targeted lncRNAs to discriminate among those groups. The study showed that the lncRNAs PACER and LNC13 were significantly upregulated in patients with active pulmonary tuberculosis at the initiation of treatment than in healthy controls. The expression levels of the two lncRNAs were significantly downregulated in patients during the treatment as compared to the active pulmonary tuberculosis patients. However, the expression levels of the lncRNAs PACER and LNC13 in whole blood of patients after six months of treatment were similar to those in healthy controls. Similarly, lncRNAs PACER and LNC13 showed very good performance in distinguishing between active tuberculosis patients and healthy controls as well as in differentiating between newly diagnosed active tuberculosis patients and those under treatment. Interestingly, those lncRNAs could not discriminate healthy controls from patients after six months of treatment. The lncRNAs PACER and LNC13 are therefore potential biomarkers for the monitoring of tuberculosis treatment.

Adipose-derived stem cells-derived exosomes facilitate cutaneous wound healing by delivering XIST and restoring discoidin domain receptor 2

BACKGROUND

Adipose-derived stem cells (ADSCs) and their derived exosomes (ADSC-Exos) have shown potential functions in tissue repair. This study focuses on the effects of ADSCs-Exos on cutaneous wound healing and the potential involvement of the long non-coding RNA (lncRNA) XIST/microRNA-96-5p (miR-96-5p)/discoidin domain receptor 2 (DDR2) axis.

METHODS

Exos were isolated from the ADSCs and identified. A mouse model of full-thickness skin wounds was established. The mice were treated with ADSC-Exos to evaluate the function of ADSC-Exos in wound healing. Mouse dermal fibroblasts (MDFs) were co-cultured with the ADSC-Exos for in vitro experiments. The most differentially expressed lncRNAs in mouse skin tissues after ADSC-Exo treatment were screened by microarray analysis. The downstream molecules were analyzed by bioinformatics tools. Gain- and loss-of-function studies were performed to examine the functions of the XIST/miR-96-5p/DDR2 axis in wound healing.

RESULTS

ADSC-Exos facilitated wound healing in mice, reduced inflammatory infiltration, and increased collagen deposition in the wound skin tissues. In vitro, the ADSC-Exos promoted proliferation, migration of the MDFs. XIST was the most upregulated lncRNA in MDFs after ADSC-Exo treatment. Downregulation of XIST suppressed the promoting role of ADSC-Exos in wound healing. XIST bound to miR-96-5p to restore the expression of DDR2 mRNA. Either silencing of miR-96-5p or overexpression of DDR2 restored the promoting functions of ADSC-Exos in proliferation and migration of MDFs.

CONCLUSION

This study demonstrates that ADSC-Exos-carried XIST accelerates cutaneous wound healing through suppressing miR-96-5p and restoring the DDR2 expression.

Bidirectional cytokine-microRNA control: A novel immunoregulatory framework in leishmaniasis

As effector innate immune cells and as a host to the protozoan parasite Leishmania, macrophages play a dual role in antileishmanial immunoregulation. The 2 key players in this immunoregulation are the macrophage-expressed microRNAs (miRNAs) and the macrophage-secreted cytokines. miRNAs, as small noncoding RNAs, play vital roles in macrophage functions including cytokines and chemokines production. In the reverse direction, Leishmania-regulated cytokines alter miRNAs expression to regulate the antileishmanial functions of macrophages. The miRNA patterns vary with the time and stage of infection. The cytokine-regulated macrophage miRNAs not only help parasite elimination or persistence but also regulate cytokine production from macrophages. Based on these observations, we propose a novel immunoregulatory framework as a scientific rationale for antileishmanial therapy.

Circulating microRNA sequencing revealed miRNome patterns in hematology and oncology patients aiding the prognosis of invasive aspergillosis

Invasive aspergillosis (IA) may occur as a serious complication of hematological malignancy. Delays in antifungal therapy can lead to an invasive disease resulting in high mortality. Currently, there are no well-established blood circulating microRNA biomarkers or laboratory tests which can be used to diagnose IA. Therefore, we aimed to define dysregulated miRNAs in hematology and oncology (HO) patients to identify biomarkers predisposing disease. We performed an in-depth analysis of high-throughput small transcriptome sequencing data obtained from the whole blood samples of our study cohort of 50 participants including 26 high-risk HO patients and 24 controls. By integrating in silico bioinformatic analyses of small noncoding RNA data, 57 miRNAs exhibiting significant expression differences (P < 0.05) were identified between IA-infected patients and non-IA HO patients. Among these, we found 36 differentially expressed miRNAs (DEMs) irrespective of HO malignancy. Of the top ranked DEMs, we found 14 significantly deregulated miRNAs, whose expression levels were successfully quantified by qRT-PCR. MiRNA target prediction revealed the involvement of IA related miRNAs in the biological pathways of tumorigenesis, the cell cycle, the immune response, cell differentiation and apoptosis.

LncRNA PCAT1 activates SOX2 and suppresses radioimmune responses via regulating cGAS/STING signalling in non-small cell lung cancer

Background

The expression of long non‐coding RNA (lncRNA) prostate cancer‐associated ncRNA transcripts 1 (PCAT1) is increased in non‐small cell lung cancer (NSCLC). It stimulates tumour growth and metastasis, but its role in the radioimmune responses remain unknown. We aimed to explore the impacts of PCAT1 on tumorigenesis and radioimmune responses and the underlying molecular mechanisms in NSCLC.

Methods

Comprehensive bioinformatics analysis was performed to identify immunosuppressive lncRNAs involved with tumour invasion in NSCLC. The expression levels of PCAT1 were analysed by in situ hybridisation in 55 paired NSCLC tissues and adjacent normal tissues. Both loss‐ and gain‐of‐function assays were performed to examine the effects of PCAT1 and SOX2 on NSCLC cell behaviours in vivo and in vitro. Bioinformatic analyses, chromatin isolation by RNA purification (ChIRP) and dual‐luciferase reporter assays were applied to validate the regulatory effects of PCAT1 on SOX2 expression. Chromatin immunoprecipitation, luciferase and rescue assays were utilised to identify the relationship between SOX2 and the cGAS/stimulator of interferon genes (STING) signalling.

Results

PCAT1 was immunosuppressive and related with NSCLC invasion. Increased PCAT1 was negatively correlated with immune cell infiltration in NSCLC. PCAT1 knockdown restrained proliferation, increased apoptosis, and repressed cell metastasis in vivo and in vitro. PCAT1 activated SOX2 that accelerated tumorigenesis and immunosuppression. SOX2 promoted tumour growth through inhibiting cytotoxic T‐cell immunity. Moreover, SOX2 restrained cGAS transcription and hampered downstream type I interferon (IFN)‐induced immune responses. Inhibition of PCAT1/SOX2 in collaboration with radiation further inhibited tumour growth, and initiated the cGAS/STING signalling pathway, which enhanced the immune responses of radiotherapy in NSCLC.

Conclusions

PCAT1/SOX2 axis promoted tumorigenesis and immunosuppression through inhibition of cGAS/STING signalling‐mediated T‐cell activation. Inhibition of PCAT1 and SOX2 synergised with radiotherapy to activate the immune response and could serve as potential therapeutic targets.

MicroRNA-155 expression with Brucella infection in vitro and in vivo and decreased serum levels of MicroRNA-155 in patients with brucellosis

Infection with Brucella is characterized by the inhibition of host immune responses. MicroRNA-155 (miR-155) has been implicated in the immune response to many diseases. In this study, its expression during Brucella 16M infection of macrophages and mice was analyzed. Expression of miR-155 was significantly induced in macrophages at 24 h post infection. Further, an analysis of infected mice showed that miR-155 was inhibited at 7 and 14 days but induced at 28 days. Interestingly, this trend in induction or inhibition was reversed at 7 and 14 days in 16M△virB-infected mice. This suggested that decreased expression of miR-155 at an early stage of infection was dependent on intracellular replication. In humans with brucellosis, serum levels of miR-155 were significantly decreased compared to those in individuals without brucellosis and healthy volunteers. Significant correlations were observed between serum level of miR-155 and serum anti-Brucella antibody titers and the sweating symptom. This effect suggests that Brucella interferes with miR-155-regulated immune responses via a unique mechanism. Taken together, data from this study indicate that Brucella infection affects miR-155 expression and that human brucellosis patients show decreased serum levels of miR-155.

Shedding Light on Autophagy During Human Tuberculosis. A Long Way to Go

Immunity against Mycobacterium tuberculosis (Mtb) is highly complex, and the outcome of the infection depends on the role of several immune mediators with particular temporal dynamics on the host microenvironment. Autophagy is a central homeostatic mechanism that plays a role on immunity against intracellular pathogens, including Mtb. Enhanced autophagy in macrophages mediates elimination of intracellular Mtb through lytic and antimicrobial properties only found in autolysosomes. Additionally, it has been demonstrated that standard anti-tuberculosis chemotherapy depends on host autophagy to coordinate successful antimicrobial responses to mycobacteria. Notably, autophagy constitutes an anti-inflammatory mechanism that protects against endomembrane damage triggered by several endogenous components or infectious agents and precludes excessive inflammation. It has also been reported that autophagy can be modulated by cytokines and other immunological signals. Most of the studies on autophagy as a defense mechanism against Mycobacterium have been performed using murine models or human cell lines. However, very limited information exists about the autophagic response in cells from tuberculosis patients. Herein, we review studies that face the autophagy process in tuberculosis patients as a component of the immune response of the human host against an intracellular microorganism such as Mtb. Interestingly, these findings might contribute to recognize new targets for the development of novel therapeutic tools to combat Mtb. Actually, either as a potential successful vaccine or a complementary immunotherapy, efforts are needed to further elucidate the role of autophagy during the immune response of the human host, which will allow to achieve protective and therapeutic benefits in human tuberculosis.

Non-Coding RNAs in the Etiology and Control of Major and Neglected Human Tropical Diseases

Non-coding RNAs (ncRNAs) including microRNAs (miRs) and long non-coding RNAs (lncRNAs) have emerged as key regulators of gene expression in immune cells development and function. Their expression is altered in different physiological and disease conditions, hence making them attractive targets for the understanding of disease etiology and the development of adjunctive control strategies, especially within the current context of mitigated success of control measures deployed to eradicate these diseases. In this review, we summarize our current understanding of the role of ncRNAs in the etiology and control of major human tropical diseases including tuberculosis, HIV/AIDS and malaria, as well as neglected tropical diseases including leishmaniasis, African trypanosomiasis and leprosy. We highlight that several ncRNAs are involved at different stages of development of these diseases, for example miR-26-5p, miR-132-3p, miR-155-5p, miR-29-3p, miR-21-5p, miR-27b-3p, miR-99b-5p, miR-125-5p, miR-146a-5p, miR-223-3p, miR-20b-5p, miR-142-3p, miR-27a-5p, miR-144-5p, miR-889-5p and miR-582-5p in tuberculosis; miR-873, MALAT1, HEAL, LINC01426, LINC00173, NEAT1, NRON, GAS5 and lincRNA-p21 in HIV/AIDS; miR-451a, miR-let-7b and miR-106b in malaria; miR-210, miR-30A-5P, miR-294, miR-721 and lncRNA 7SL RNA in leishmaniasis; and miR-21, miR-181a, miR-146a in leprosy. We further report that several ncRNAs were investigated as diseases biomarkers and a number of them showed good potential for disease diagnosis, including miR-769-5p, miR-320a, miR-22-3p, miR-423-5p, miR-17-5p, miR-20b-5p and lncRNA LOC152742 in tuberculosis; miR-146b-5p, miR-223, miR-150, miR-16, miR-191 and lncRNA NEAT1 in HIV/AIDS; miR-451 and miR-16 in malaria; miR-361-3p, miR-193b, miR-671, lncRNA 7SL in leishmaniasis; miR-101, miR-196b, miR-27b and miR-29c in leprosy. Furthermore, some ncRNAs have emerged as potential therapeutic targets, some of which include lncRNAs NEAT1, NEAT2 and lnr6RNA, 152742 in tuberculosis; MALAT1, HEAL, SAF, lincRNA-p21, NEAT1, GAS5, NRON, LINC00173 in HIV/AIDS; miRNA-146a in malaria. Finally, miR-135 and miR-126 were proposed as potential targets for the development of therapeutic vaccine against leishmaniasis. We also identify and discuss knowledge gaps that warrant for increased research work. These include investigation of the role of ncRNAs in the etiology of African trypanosomiasis and the assessment of the diagnostic potential of ncRNAs for malaria, and African trypanosomiasis. The potential targeting of ncRNAs for adjunctive therapy against tuberculosis, leishmaniasis, African trypanosomiasis and leprosy, as well as their targeting in vaccine development against tuberculosis, HIV/AIDS, malaria, African trypanosomiasis and leprosy are also new avenues to explore.