MiR-326-mediated overexpression of NFIB offsets TGF-ß induced epithelial to mesenchymal transition and reverses lung fibrosis.

Idiopathic Pulmonary Fibrosis (IPF) is a progressively fatal and incurable disease characterized by the loss of alveolar structures, increased epithelial-mesenchymal transition (EMT), and aberrant tissue repair. In this study, we investigated the role of Nuclear Factor I-B (NFIB), a transcription factor critical for lung development and maturation, in IPF. Using both human lung tissue samples from patients with IPF, and a mouse model of lung fibrosis induced by bleomycin, we showed that there was a significant reduction of NFIB both in the lungs of patients and mice with IPF. Furthermore, our in vitro experiments using cultured human lung cells demonstrated that the loss of NFIB was associated with the induction of EMT by transforming growth factor beta (TGF-ß). Knockdown of NFIB promoted EMT, while overexpression of NFIB suppressed EMT and attenuated the severity of bleomycin-induced lung fibrosis in mice. Mechanistically, we identified post-translational regulation of NFIB by miR-326, a miRNA with anti-fibrotic effects that is diminished in IPF. Specifically, we showed that miR-326 stabilized and increased the expression of NFIB through its 3'UTR target sites for Human antigen R (HuR). Moreover, treatment of mice with either NFIB plasmid or miR-326 reversed airway collagen deposition and fibrosis. In conclusion, our study emphasizes the critical role of NFIB in lung development and maturation, and its reduction in IPF leading to EMT and loss of alveolar structures. Our study highlights the potential of miR-326 as a therapeutic intervention for IPF. The schema shows the role of NFIB in maintaining the normal epithelial cell characteristics in the lungs and how its reduction leads to a shift towards mesenchymal cell-like features and pulmonary fibrosis. A In normal lungs, NFIB is expressed abundantly in the epithelial cells, which helps in maintaining their shape, cell polarity and adhesion molecules. However, when the lungs are exposed to factors that induce pulmonary fibrosis, such as bleomycin, or TGF-ß, the epithelial cells undergo epithelial to mesenchymal transition (EMT), which leads to a decrease in NFIB. B The mesenchymal cells that arise from EMT appear as spindle-shaped with loss of cell junctions, increased cell migration, loss of polarity and expression of markers associated with mesenchymal cells/fibroblasts. C We designed a therapeutic approach that involves exogenous administration of NFIB in the form of overexpression plasmid or microRNA-326. This therapeutic approach decreases the mesenchymal cell phenotype and restores the epithelial cell phenotype, thus preventing the development or progression of pulmonary fibrosis.

Surface-Engineered Mucus Penetrating Nucleic Acid Delivery Systems with Cell Penetrating Peptides for the Lungs.

Nucleic acids, both DNA and small RNAs, have emerged as potential therapeutics for the treatment of various lung disorders. However, delivery of nucleic acids to the lungs is challenging due to the barrier property imposed by mucus, which is further reinforced in disease conditions such as chronic obstructive pulmonary disease and asthma. The presence of negatively charged mucins imparts the electrostatic barrier property, and the mesh network structure of mucus provides steric hindrance to the delivery system. To overcome this, the delivery system either needs to be muco-inert with a low positive charge such that the interactions with mucus are minimized or should have the ability to transiently dismantle the mucus structure for effective penetration. We have developed a mucus penetrating system for the delivery of both small RNA and plasmid DNA independently. The nucleic acid core consists of a nucleic acid (pDNA/siRNA) and a cationic/amphipathic cell penetrating peptide. The mucus penetrating coating consists of the hydrophilic biopolymer chondroitin sulfate A (CS-A) conjugated with a mucolytic agent, mannitol. We hypothesize that the hydrophilic coating of CS-A would reduce the surface charge and decrease the interaction with negatively charged mucins, while the conjugated mannitol residues would disrupt the mucin-mucin interaction or decrease the viscosity of mucus by increasing the influx of water into the mucus. Our results indicate that CS-A-mannitol-coated nanocomplexes possess reduced surface charge, reduced viscosity of artificial mucus, and increased diffusion in mucin suspension as well as increased penetration through the artificial mucus layer as compared to the non-coated ones. Further, the coated nanocomplexes showed low cytotoxicity as well as higher transfection in A-549 and BEAS-2B cells as compared to the non-coated ones.

MiRNA-137-mediated modulation of mitochondrial dynamics regulates human neural stem cell fate.

The role of miRNAs in determining human neural stem cell (NSC) fate remains elusive despite their high expression in the developing nervous system. In this study, we investigate the role of miR-137, a brain-enriched miRNA, in determining the fate of human induced pluripotent stem cells-derived NSCs (hiNSCs). We show that ectopic expression of miR-137 in hiNSCs reduces proliferation and accelerates neuronal differentiation and migration. TargetScan and MicroT-CDS predict myocyte enhancer factor-2A (MEF2A), a transcription factor that regulates peroxisome proliferator-activated receptor-gamma coactivator (PGC1α) transcription, as a target of miR-137. Using a reporter assay, we validate MEF2A as a downstream target of miR-137. Our results indicate that reduced levels of MEF2A reduce the transcription of PGC1α, which in turn impacts mitochondrial dynamics. Notably, miR-137 accelerates mitochondrial biogenesis in a PGC1α independent manner by upregulating nuclear factor erythroid 2 (NFE2)-related factor 2 (NRF2) and transcription factor A of mitochondria (TFAM). In addition, miR-137 modulates mitochondrial dynamics by inducing mitochondrial fusion and fission events, resulting in increased mitochondrial content and activation of oxidative phosphorylation (OXPHOS) and oxygen consumption rate. Pluripotency transcription factors OCT4 and SOX2 are known to have binding sites in the promoter region of miR-137 gene. Ectopic expression of miR-137 elevates the expression levels of OCT4 and SOX2 in hiNSCs which establishes a feed-forward self-regulatory loop between miR-137 and OCT4/SOX2. Our study provides novel molecular insights into NSC fate determination by miR-137.

Adhatoda Vasica attenuates inflammatory and hypoxic responses in preclinical mouse models: potential for repurposing in COVID-19-like conditions.

BACKGROUND: COVID-19 pneumonia has been associated with severe acute hypoxia, sepsis-like states, thrombosis and chronic sequelae including persisting hypoxia and fibrosis. The molecular hypoxia response pathway has been associated with such pathologies and our recent observations on anti-hypoxic and anti-inflammatory effects of whole aqueous extract of Adhatoda Vasica (AV) prompted us to explore its effects on relevant preclinical mouse models. METHODS: In this study, we tested the effect of whole aqueous extract of AV, in murine models of bleomycin induced pulmonary fibrosis, Cecum Ligation and Puncture (CLP) induced sepsis, and siRNA induced hypoxia-thrombosis phenotype. The effect on lung of AV treated naïve mice was also studied at transcriptome level. We also determined if the extract may have any effect on SARS-CoV2 replication. RESULTS: Oral administration AV extract attenuates increased airway inflammation, levels of transforming growth factor-ß1 (TGF-ß1), IL-6, HIF-1α and improves the overall survival rates of mice in the models of pulmonary fibrosis and sepsis and rescues the siRNA induced inflammation and associated blood coagulation phenotypes in mice. We observed downregulation of hypoxia, inflammation, TGF-ß1, and angiogenesis genes and upregulation of adaptive immunity-related genes in the lung transcriptome. AV treatment also reduced the viral load in Vero cells infected with SARS-CoV2. CONCLUSION: Our results provide a scientific rationale for this ayurvedic herbal medicine in ameliorating the hypoxia-hyperinflammation features and highlights the repurposing potential of AV in COVID-19-like conditions.

Novel nuclear translocation of inositol polyphosphate 4-phosphatase is associated with cell cycle, proliferation and survival.

Inositol polyphosphate 4 phosphatase type I enzyme (INPP4A) has a well-documented function in the cytoplasm where it terminates the phosphatidylinositol 3-kinase (PI 3-K) pathway by acting as a negative regulator. In this study, we demonstrate for the first time that INPP4A shuttles between the cytoplasm and the nucleus. Nuclear INPP4A is enzymatically active and in dynamic equilibrium between the nucleus and cytoplasm depending on the cell cycle stage, with highest amounts detected in the nucleus during the G0/G1 phase. Moreover, nuclear INPP4A is found to have direct proliferation suppressive activity. Cells constitutively overexpressing nuclear INPP4A exhibit massive apoptosis. In human tissues as well as cell lines, lower nuclear localization of INPP4A correlate with cancerous growth. Together, our findings suggest that nuclear compartmentalization of INPP4A may be a mechanism to regulate cell cycle progression, proliferation and apoptosis. Our results imply a role for nuclear-localized INPP4A in tumor suppression in humans.

Secretory Inositol Polyphosphate 4-Phosphatase Protects against Airway Inflammation and Remodeling.

The asthma candidate gene inositol polyphosphate 4-phosphatase type I A (INPP4A) is a lipid phosphatase that negatively regulates the PI3K/Akt pathway. Destabilizing genetic variants of INPP4A increase the risk of asthma, and lung-specific INPP4A knockdown induces asthma-like features. INPP4A is known to localize intracellularly, and its extracellular presence has not been reported yet. Here we show for the first time that INPP4A is secreted by airway epithelial cells and that extracellular INPP4A critically inhibits airway inflammation and remodeling. INPP4A was present in blood and BAL fluid, and this extracellular INPP4A was reduced in patients with asthma and mice with allergic airway inflammation. In both naive mice and mice with allergic airway inflammation, antibody-mediated neutralization of extracellular INPP4A potentiated PI3K/Akt signaling and induced airway hyperresponsiveness, with prominent airway remodeling, subepithelial fibroblast proliferation, and collagen deposition. The link between extracellular INPP4A and fibroblasts was investigated in vitro. Cultured airway epithelial cells secreted enzymatically active INPP4A in extracellular vesicles and in a free form. Extracellular vesicle-mediated transfer of labeled INPP4A, from epithelial cells to fibroblasts, was observed. Inhibition of such transfer by anti-INPP4A antibody increased fibroblast proliferation. We propose that secretory INPP4A is a novel "paracrine" layer of the intricate regulation of lung homeostasis, by which airway epithelium dampens PI3K/Akt signaling in inflammatory cells or local fibroblasts, thereby limiting inflammation and remodeling.

Miro1 regulates intercellular mitochondrial transport & enhances mesenchymal stem cell rescue efficacy.

There is emerging evidence that stem cells can rejuvenate damaged cells by mitochondrial transfer. Earlier studies show that epithelial mitochondrial dysfunction is critical in asthma pathogenesis. Here we show for the first time that Miro1, a mitochondrial Rho-GTPase, regulates intercellular mitochondrial movement from mesenchymal stem cells (MSC) to epithelial cells (EC). We demonstrate that overexpression of Miro1 in MSC (MSCmiro(Hi)) leads to enhanced mitochondrial transfer and rescue of epithelial injury, while Miro1 knockdown (MSCmiro(Lo)) leads to loss of efficacy. Treatment with MSCmiro(Hi) was associated with greater therapeutic efficacy, when compared to control MSC, in mouse models of rotenone (Rot) induced airway injury and allergic airway inflammation (AAI). Notably, airway hyperresponsiveness and remodeling were reversed by MSCmiro(Hi) in three separate allergen-induced asthma models. In a human in vitro system, MSCmiro(Hi) reversed mitochondrial dysfunction in bronchial epithelial cells treated with pro-inflammatory supernatant of IL-13-induced macrophages. Anti-inflammatory MSC products like NO, TGF-ß, IL-10 and PGE2, were unchanged by Miro1 overexpression, excluding non-specific paracrine effects. In summary, Miro1 overexpression leads to increased stem cell repair.

IL-4 promotes asymmetric dimethylarginine accumulation, oxo-nitrative stress, and hypoxic response-induced mitochondrial loss in airway epithelial cells.

BACKGROUND: Obesity is known to increase asthma risk and severity. Increased levels of asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, are associated with mitochondrial toxicity, asthma, and metabolic syndrome. IL-4 upregulates the expression of protein arginine methyltransferases, which are essential for ADMA formation. Importantly, cross-talk between IL-4, ADMA, and mitochondrial dysfunction could explain how obesity and IL-4 can synergize to exacerbate allergic inflammation. OBJECTIVE: We sought to investigate how IL-4, a key asthma-associated cytokine, can influence ADMA-related effects on lungs. METHODS: BEAS2B (bronchial epithelial) cells were treated with IL-4 followed by ADMA and investigated for oxo-nitrative stress and resultant mitochondrial toxicity after 48 hours by using flow cytometry, confocal imaging, immunoblotting, and fluorimetric assays. RESULTS: IL-4-induced mitotoxicity in BEAS2B cells was significantly higher in the presence of exogenous ADMA. IL-4 treatment led to proteolytic degradation of dimethylarginine dimethylaminohydrolase 2, which catabolizes ADMA. IL-4 pretreatment was associated with increased intracellular ADMA accumulation and increased ADMA-induced mitotoxicity. Airway epithelial cells treated with IL-4 followed by ADMA showed exaggerated oxo-nitrative stress and potent induction of the cellular hypoxic response, despite normoxic conditions. The hypoxic response was associated with reduced mitochondrial function but was reversible by overexpression of the mitochondrial biogenesis factor, mitochondrial transcription factor A. CONCLUSION: We conclude that IL-4 promotes intracellular ADMA accumulation, leading to mitochondrial loss through oxo-nitrative stress and hypoxic response. This provides a novel understanding of how obesity, with high ADMA levels, and asthma, with high IL-4 levels, might potentiate each other and highlights the potential of mitochondrial-targeted therapeutics in obese subjects with asthma.

Hyperinsulinemia adversely affects lung structure and function.

There is limited knowledge regarding the consequences of hyperinsulinemia on the lung. Given the increasing prevalence of obesity, insulin resistance, and epidemiological associations with asthma, this is a critical lacuna, more so with inhaled insulin on the horizon. Here, we demonstrate that insulin can adversely affect respiratory health. Insulin treatment (1 µg/ml) significantly (P < 0.05) increased the proliferation of primary human airway smooth muscle (ASM) cells and induced collagen release. Additionally, ASM cells showed a significant increase in calcium response and mitochondrial respiration upon insulin exposure. Mice administered intranasal insulin showed increased collagen deposition in the lungs as well as a significant increase in airway hyperresponsiveness. PI3K/Akt mediated activation of ß-catenin, a positive regulator of epithelial-mesenchymal transition and fibrosis, was observed in the lungs of insulin-treated mice and lung cells. Our data suggests that hyperinsulinemia may have adverse effects on airway structure and function. Insulin-induced activation of ß-catenin in lung tissue and the contractile effects on ASM cells may be causally related to the development of asthma-like phenotype.

Safranal of Crocus sativus L. inhibits inducible nitric oxide synthase and attenuates asthma in a mouse model of asthma.

The present study involves evaluation of antioxidant potential of Crocus sativus and its main constituents, safranal (SFN) and crocin (CRO), in bronchial epithelial cells, followed antiinflammatory potential of the active constituent safranal, in a murine model of asthma. To investigate the antioxidizing potential of Crocus sativus and its main constituents in bronchial epithelial cells, the stress was induced in these cells by a combination of different cytokines that resulted in an increase in nitric oxide production (NO), induced nitric oxide synthase (iNOS) levels, peroxynitrite ion generation, and cytochrome c release. Treatment with saffron and its constituents safranal and crocin resulted in a decrease of NO, iNOS levels, peroxynitrite ion generation, and prevented cytochrome c release. However, safranal significantly reduced oxidative stress in bronchial epithelial cells via iNOS reduction besides preventing apoptosis in these cells. In the murine model of asthma study, antiinflammatory role of safranal was characterized by increased airway hyper-responsiveness, airway cellular infiltration, and epithelial cell injury. Safranal pretreatment to these allergically inflamed mice lead to a significant decrease in airway hyper-responsiveness and airway cellular infiltration to the lungs. It also reduced iNOS production, bronchial epithelial cell apoptosis, and Th2 type cytokine production in the lungs.

MicroRNA-326 regulates profibrotic functions of transforming growth factor-ß in pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a fatal disorder resulting from the progressive remodeling of lungs, with no known effective treatment. Although transforming growth factor (TGF)-ß has a well-established role in lung fibrosis, clinical experience with neutralizing antibodies to TGF-ß has been disappointing, and strategies to directly suppress TGF-ß1 secretion are needed. In this study we used a combination of in silico, in vitro, and in vivo approaches to identify microRNAs involved in TGF-ß1 regulation and to validate the role of miR-326 in pulmonary fibrosis.We show that hsa-miR-326 regulates TGF-ß1 expression and that hsa-miR-326 levels are inversely correlated to TGF-ß1 protein levels in multiple human cell lines. The increase in TGF-ß1 expression during the progression of bleomycin-induced lung fibrosis in mice was associated with loss of mmu-miR-326. Restoration of mmu-miR-326 levels by intranasal delivery of miR-326 mimics was sufficient to inhibit TGF-ß1 expression and attenuate the fibrotic response. Moreover, human IPF lung specimens had markedly diminished miR-326 expression as compared with nonfibrotic lungs. Additional targets of miR-326 controlling TGF-ß signaling and fibrosis-related pathways were identified, and miR-326 was found to down-regulate profibrotic genes, such as Ets1, Smad3, and matrix metalloproteinase 9, whereas it up-regulates antifibrotic genes, such as Smad7. Our results suggest for the first time that miR-326 plays a key role in regulating TGF-ß1 expression and other profibrotic genes and could be useful in developing better therapeutic strategies for alleviating lung fibrosis.

Mapping the genetic architecture of idiopathic pulmonary fibrosis: Meta-analysis and epidemiological evidence of case-control studies.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a rare and devastating fibrotic lung disorder with unknown etiology. Although it is believed that genetic component is an important risk factor for IPF, a comprehensive understanding of its genetic landscape is lacking. Hence, we aimed to highlight the susceptibility genes and pathways implicated in IPF pathogenesis through a two-staged systematic literature search of genetic association studies on IPF, followed by meta-analysis and pathway enrichment analysis. METHODS: This study was performed based on PRISMA guidelines (PROSPERO, registration number: CRD42022297970). The first search was performed (using PubMed and Web of Science) retrieving a total of 5642 articles, of which 52 were eligible for inclusion in the first stage. The second search was performed (using PubMed, Web of Science and Scopus) for ten polymorphisms, identified from the first search, with 2 or more studies. Finally, seven polymorphisms, [rs35705950/MUC5B, rs2736100/TERT, rs2609255/FAM13A, rs2076295/DSP, rs12610495/DPP9, rs111521887/TOLLIP and rs1800470/TGF-ß1] qualified for meta-analyses. The epidemiological credibility was evaluated using Venice criteria. RESULTS: From the systematic review, 222 polymorphisms in 118 genes showed a significant association with IPF susceptibility. Meta-analyses findings revealed significant association of rs35705950/T [OR = 3.92(3.26-4.57)], rs2609255/G [OR = 1.50(1.18-1.82)], rs2076295/G [OR = 1.19(0.82-1.756)], rs12610495/G [OR = 1.28(1.12-1.44)], rs2736100/C [OR = 0.68(0.54-0.82), rs111521887/G [OR = 1.34(1.06-1.61)] and suggestive evidence for rs1800470/T [OR = 1.08(0.82-1.34)] with IPF susceptibility. Four polymorphisms- rs35705950/MUC5B, rs2736100/TERT, rs2076295/DSP and rs111521887/TOLLIP, exhibited substantial epidemiological evidence supporting their association with IPF risk. Gene ontology and pathway enrichment analysis performed on IPF risk-associated genes identified a critical role of genes in mucin production, immune response and inflammation, host defence, cell-cell adhesion and telomere maintenance. CONCLUSIONS: Our findings present the most prominent IPF-associated genetic risk variants involved in alveolar epithelial injuries (MUC5B, TERT, FAM13A, DSP, DPP9) and epithelial-mesenchymal transition (TOLLIP, TGF-ß1), providing genetic and biological insights into IPF pathogenesis. However, further experimental research and human studies with larger sample sizes, diverse ethnic representation, and rigorous design are warranted.

Plausible role of INPP4A dysregulation in idiopathic pulmonary fibrosis.

INPP4A has been shown to be involved in the regulation of cell proliferation and apoptosis of multiple cell types including fibroblasts. Previous reports from our group have demonstrated the role of inositol polyphosphate 4-phosphatase Type I A (INPP4A) in these functions. Though existing evidences suggest a critical role for INPP4A in the maintenance of lung homeostasis, its role in chronic lung diseases is relatively under explored. In the current study, we made an attempt to understand the regulation of INPP4A in idiopathic pulmonary fibrosis (IPF). Through integration of relevant INPP4A gene expression data from public repositories with our results from in vitro experiments and mouse models, we show that INPP4A is altered in IPF. Interestingly, the direction of the change is dependent both on the disease stage and the region of the lung used. INPP4A was found to be upregulated when analyzed in lung sample representative of the whole lung, but was downregulated in the fibrotic regions of the lung. Similarly, INPP4A was found to be high, compared to controls, only in the early stage of the disease. Though the observed increase in INPP4A was found to be negatively correlated to physiological indices, FVC, and DLCO, of lung function, treatment with anti-INPP4A antibody worsened the condition in bleomycin treated mice. These contrasting results taken together are suggestive of a nuanced regulation of INPP4A in IPF which is dependent on the disease stage, cellular state and extent of fibrosis in the lung region being analyzed.

MicroRNAs in exhaled breath condensate: A pilot study of biomarker detection for lung cancer.

INTRODUCTION: Quantitation of microRNAs secreted by lung cells can provide valuable information regarding lung health. Exhaled breath condensate (EBC) offers a non-invasive way to sample the secreted microRNAs, and could be used as diagnostic tools for lung cancer. MATERIALS & METHODS: EBC samples from twenty treatment-naïve patients with pathologically confirmed lung cancer and twenty healthy subjects were profiled for miRNAs expression. Selected microRNAs were further validated, using quantitative-PCR, in an independent set of 10 subjects from both groups. RESULTS: A total of 78 miRNAs were found to be significantly upregulated in the EBC of lung cancer patients compared to the control group. Six of these 78 miRNAs were shortlisted for validation. Of these, miR-31-3p, let7i, and miR-449c were significantly upregulated, exhibited good discriminatory power. DISCUSSION: Differential expression of miRNAs secreted by lung cells could be quantitated in EBC samples, and could be used as a potential non-invasive tool for early diagnosis of lung cancer.

A review on electronic nose for diagnosis and monitoring treatment response in lung cancer.

Lung cancer is one of the common malignancies with high mortality rate and a poor prognosis. Most lung cancer cases are diagnosed at an advanced stage either due to limited resources of infrastructure, trained human resources, or delay in clinical suspicion. Low-dose computed tomography has emerged as a screening tool for lung cancer detection but this may not be a feasible option for most developing countries. Electronic nose is a unique non-invasive device that has been developed for lung cancer diagnosis and monitoring response by exhaled breath analysis of volatile organic compounds. The breath-print have been shown to differ not only among lung cancer and other respiratory diseases, but also between various types of lung cancer. Hence, we postulate that the breath-print analysis by electronic nose could be a potential biomarker for the early detection of lung cancer along with monitoring treatment response in a resource-limited setting. In this review, we have consolidated the current published literature suggesting the use of an electronic nose in the diagnosis and monitoring treatment response of lung cancer.

microRNAs in exhaled breath condensate for diagnosis of lung cancer in a resource-limited setting: a concise review.

Lung cancer is one of the common cancers globally with high mortality and poor prognosis. Most cases of lung cancer are diagnosed at an advanced stage due to limited diagnostic resources. Screening modalities, such as sputum cytology and annual chest radiographs, have not proved sensitive enough to impact mortality. In recent years, annual low-dose computed tomography has emerged as a potential screening tool for early lung cancer detection, but it may not be a feasible option for developing countries. In this context, exhaled breath condensate (EBC) analysis has been evaluated recently as a noninvasive tool for lung cancer diagnosis. The breath biomarkers also have the advantage of differentiating various types and stages of lung cancer. Recent studies have focused more on microRNAs (miRNAs) as they play a key role in tumourigenesis by regulating the cell cycle, metastasis and angiogenesis. In this review, we have consolidated the current published literature suggesting the utility of miRNAs in EBC for the detection of lung cancer.

Hypoxia response in asthma: differential modulation on inflammation and epithelial injury.

Oxygen-sensing prolyl-hydroxylase (PHD)-2 negatively regulates hypoxia-inducible factor (HIF)1-α and suppresses the hypoxic response. Hypoxia signaling is thought to be proinflammatory but also attenuates cellular injury and apoptosis. Although increased hypoxic response has been noted in asthma, its functional relevance is unknown. The objectives of this study were to dissect the mechanisms and role of the hypoxic response in asthma pathophysiology. Experimental studies were conducted in mice using acute and chronic allergic models of asthma. The hypoxic response in allergically inflamed lungs was modulated by using pharmacologic PHD inhibitors (ethyl-3-4-dihydroxybenzoic acid [DHB], 1-10 mg/kg) or siRNA-mediated genetic knockdowns. Increased hypoxia response led to exacerbation of the asthma phenotype, with HIF-1α knockdown being beneficial. Chronically inflamed lungs from mice treated with 10 mg/kg DHB showed diffuse up-regulation of the hypoxia response, severe airway remodeling, and inflammation. Fatal asphyxiation during methacholine challenge was noted. However, bronchial epithelium restricted up-regulation of the hypoxia response seen with low-dose DHB (1 mg/kg) reduced epithelial injury and attenuated the asthmatic phenotype. Up-regulation of the hypoxia response was associated with increased expression of CX3CR1, a lymphocyte survival factor, and increased inflammatory cell infiltrate. This study shows that an exaggerated hypoxia response may contribute to airway inflammation, remodeling, and the development of asthma. However, the hypoxia response may also be protective of epithelial apoptosis at lower levels, and the net effects of modulating the hypoxia response may vary based on the context.

Micro RNAs as potential biomarkers in tuberculosis: A systematic review.

Tuberculosis (TB) remains a major infectious disease across the globe. With increasing TB infections and a rise in multi-drug resistance, rapid diagnostic modalities are required to achieve TB control. Radiological investigations and microbiological tests (microscopic examination, cartridge-based nucleic acid amplification tests, and cultures) are most commonly used to diagnose TB. Histopathological/cytopathological examinations are also required for an accurate diagnosis in many patients. The causative agent, Mycobacterium tuberculosis (Mtb), is known to circumvent the host's immune system. Circulating microRNAs (miRNAs) play a crucial role in biological pathways and can be used as a potential biomarker to detect tuberculosis. miRNAs are small non-coding RNAs and negatively regulate gene expression during post-transcriptional regulation. The differential expression of miRNAs in multiple clinical samples in tuberculosis patients may be helpful as potential disease biomarkers. This review summarizes the literature on miRNAs in various clinical samples as biomarkers for TB diagnosis.

Clinical Profile of 327 patients with Sarcoidosis in India: An Ambispective Cohort Study in a Tuberculosis (TB) Endemic Population.

INTRODUCTION: Sarcoidosis is a multisystem granulomatous disease with a varied clinical presentation. We describe the clinical characteristics of patients with sarcoidosis from a tuberculosis (TB) endemic setting. METHODS: We performed an analysis of the sarcoidosis database at a tertiary care facility in North India. RESULTS: Of the 327 patients, 50.8% were male, with a mean age of 42.8 years (range: 16-70 years). Females were significantly older. 42.6% had comorbidities, of which diabetes (17.1%) was most common. More than half (57.1%) were obese. Serum angiotensin-converting enzyme levels were elevated in 186 (57.9%). Eleven (3.8%) had hypercalcemia, while hypercalciuria was present in 54 (31.7%). The majority (89.9%) were tuberculin skin test negative (<10 mm induration), while 71.9% were tuberculin anergic. 47.7% had normal spirometry, while a restrictive impairment was the most common abnormality (44.6%). Obstruction on spirometry was present in 8.3%. Nearly half (160, 49%) had involvement of an extrapulmonary site. Most patients were (96%) symptomatic. Cough, shortness of breath, fatigue, weight loss, and fever were the predominant symptoms. A majority had Stage 1 (47.7%) sarcoidosis. Two hundred and eighty-seven (87.8%) patients underwent bronchoscopy or endosonographic (endobronchial ultrasound-guided transbronchial needle aspiration [EBUS-TBNA] or transesophageal bronchoscopic ultrasound-guided fine-needle aspiration [EUS-B-FNA]) sampling. A histopathological diagnosis with the demonstration of granulomas was achieved in 90.8%. The diagnostic yield of EBUS-TBNA/EUS-B-FNA was 77.4%. In 13.5% of patients, necrotizing granulomas were present in tissue samples. CONCLUSION: The clinical profile of patients with sarcoidosis in TB endemic settings has certain differences from nonendemic populations. Bronchoscopy and endosonography allow a confident diagnosis in the majority of patients.

Patient profile and comparison of three diagnostic criteria for cardiac sarcoidosis in a tuberculosis endemic population.

BACKGROUND: Cardiac sarcoidosis (CS) is an underdiagnosed and life-threatening condition. Histopathological diagnosis is difficult due to the risks and variable diagnostic yield of endomyocardial biopsy. OBJECTIVES: To study the clinical profile and compare the diagnostic criteria of CS in a cohort of sarcoidosis. METHODS: A retrospective review of the Sarcoidosis database (375 patients) was performed to identify patients with CS. Demographic and clinical details were retrieved. We applied the available diagnostic criteria for the diagnosis of CS: The World Association of Sarcoidosis and Other Granulomatous Diseases (WASOG), Heart Rhythm Society (HRS), and Japanese Ministry of Health and Welfare (JMHW) criteria. RESULTS: Out of the 375 patients, 15 (4%) were identified with CS. The median age was 41 years, and 53% were female. The most common symptoms were breathlessness, palpitation, and fatigue in 80%, 53.3%, and 46.6% of patients, respectively. Tuberculin positivity (≥ 10mm induration) was seen in 26.6%. 80% and 53.3% of the patients had abnormal ECG and 2D echocardiography findings, respectively. Six patients had a history of Ventricular tachycardia (40%). LV Ejection fraction was reduced in 12 subjects (80%). Cardiac-MRI showed late gadolinium enhancement in 53.3%. A definitive histopathological diagnosis for sarcoidosis was established in 86.6% (13/15) patients. Of the 15, all satisfied JMHW criteria and WASOG criteria (12 (80%) at least probable category, 3 (20%) possible CS), and 13 (86.6%) met HRS criteria for a diagnosis of CS. CONCLUSION: In a cohort of 375 patients with sarcoidosis in a tuberculosis endemic setting, 4% were diagnosed with cardiac sarcoidosis. Histopathological diagnosis may be obtained by sampling from extracardiac sites. JMHW and WASOG criteria perform equally well in TB endemic settings.