TGF-β1 T869C polymorphism may affect susceptibility to idiopathic pulmonary fibrosis and disease severity. Lung. 2013;191:199-205. [PMID: 23344525 DOI: 10.1007/s00408-012-9447-z]

Structural impact, ligand-protein interactions, and molecular phenotypic effects of TGF-β1 gene variants: In silico analysis with implications for idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic Pulmonary Fibrosis (IPF) is a chronic interstitial lung disease resulting in progressively deteriorating lung function. Transforming growth factor-β1 (TGF-β1) belongs to the TGF superfamily and exerts a profibrotic role in promoting lung fibrosis by facilitating fibroblast infiltration and activity, extracellular matrix deposition, and inhibition of collagen breakdown, thus promoting tissue remodelling and IPF.

MATERIALS AND METHODS

We evaluated the link between pathogenic TGF-β1 SNPs and IPF pathogenesis and the structure-activity functional consequences of those SNPs on the TGF-β1 protein. Several computational algorithms were merged to address the functional consequences of TGF-β1 gene mutations to protein stability, putative post-translational modification sites, ligand-protein interactions, and molecular phenotypic effects. These included FATHMM, POLYPHEN2, PROVEAN, and SIFT tools (identifying deleterious nsSNPs in the TGF-β1 gene), along with Pmut, PhD-SNP, SNAP, MutPred and the related TMHMM, MARCOIL, and DisProt algorithms (predicting structural disorders). INPS-MD was also used to evaluate the mutation-induced TGF-β1 protein's stability and MODPRED for recognition of post-translational TGF-β1 modification.

RESULTS

In total, 14 major pathogenic variants markedly impact the destabilization of the TGF-β1 protein, with most of these high-risk mutations associated with decreased stability of the TGF-β1 protein as per the I-Mutant, MUpro, and INPS-MD tools. R205W, R185W, R180Q, D86Y, and I300T variants were proposed to participate in the post-translational modifications, thus affecting affect protein-ligand interactions. Furthermore, at-risk genetic variants appear to target conserved regions in the alpha helices, random coils, and extracellular loops, resulting in a varied composition of amino acids, charge, hydrophobicity, and spatial architecture.

CONCLUSIONS

This study manuscript comprehensively analyzes gene variants within the TGF-β1 gene, offering novel insights into their structural and functional implications in interacting with target sites. This study is significant for the development of targeted therapeutic strategies and personalized treatment approaches for patients with inflammatory lung diseases such as IPF.

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-β1] 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-β1), 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.

Post-tuberculosis lung disease and inflammatory role players: can we characterise the myriad inflammatory pathways involved to gain a better understanding?

Tuberculosis (TB) remains a global health threat, and even after successful TB treatment, a subset of patients develops serious long-term lung impairments, recently termed post-tuberculosis lung disease (PTLD). Much remains to be discovered, as PTLD as a post-TB disease is a developing field, still in its infancy. The pathogenesis of PTLD is not fully elucidated but has been linked to elevated inflammatory pathways. The complexity of PTLD makes it challenging to pinpoint the specific inflammatory pathways involved in its pathophysiology. Therefore, this paper provides a comprehensive review of inflammatory cytokines and their potential roles in PLTD, with a specific focus on interleukin 6 (IL-6), IL-1, IL-8, tumour necrosis factor-alpha (TNF-α), transforming growth factor beta (TGF-β) and C-Reactive Protein (CRP). We delve into PTLD pathology, discuss its impact on lung function and review risk factors for PTLD. In addition, we summarise the current gaps in knowledge, provide recommendations for measuring inflammatory biomarkers and propose potential directions for future studies. We propose that future studies measure a wide range of inflammatory markers in TB populations with and without PTLD. In addition, studies could isolate peripheral blood mononuclear cells from patient blood to try and identify possible impairments that could be correlated with a PTLD diagnosis. Given that the PTLD field is still in an early stage of development, a comprehensive inflammatory analysis may help to know which pathways are key in PTLD development, and this may ultimately help to predict patients who are at risk. More research is warranted.

Wild-type S100A3 and S100A13 restore calcium homeostasis and mitigate mitochondrial dysregulation in pulmonary fibrosis patient-derived cells

Patients with digenic S100A3 and S100A13 mutations exhibited an atypical and progressive interstitial pulmonary fibrosis, with impaired intracellular calcium homeostasis and mitochondrial dysfunction. Here we provide direct evidence of a causative effect of the mutation on receptor mediated calcium signaling and calcium store responses in control cells transfected with mutant S100A3 and mutant S100A13. We demonstrate that the mutations lead to increased mitochondrial mass and hyperpolarization, both of which were reversed by transfecting patient-derived cells with the wild type S100A3 and S100A13, or extracellular treatment with the recombinant proteins. In addition, we demonstrate increased secretion of inflammatory mediators in patient-derived cells and in control cells transfected with the mutant-encoding constructs. These findings indicate that treatment of patients' cells with recombinant S100A3 and S100A13 proteins is sufficient to normalize most of cellular responses, and may therefore suggest the use of these recombinant proteins in the treatment of this devastating disease.

Precision medicine advances in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a highly heterogeneous, unpredictable and ultimately lethal chronic lung disease. Over the last decade, two anti-fibrotic agents have been shown to slow disease progression, however, both drugs are administered uniformly with minimal consideration of disease severity and inter-individual molecular, genetic, and genomic differences. Advances in biological understanding of disease endotyping and the emergence of precision medicine have shown that "a one-size-fits-all approach" to the management of chronic lung diseases is no longer appropriate. While precision medicine approaches have revolutionized the management of other diseases such as lung cancer and asthma, the implementation of precision medicine in IPF clinical practice remains an unmet need despite several reports demonstrating a large number of diagnostic, prognostic and theragnostic biomarker candidates in IPF. This review article aims to summarize our current knowledge of precision medicine in IPF and highlight barriers to translate these research findings into clinical practice.

Genetic variations in idiopathic pulmonary fibrosis and patient response to pirfenidone

BACKGROUND

Genetic variations in Idiopathic Pulmonary Fibrosis (IPF) affect survival and outcomes. Current antifibrotic agents are managed based on the patient's reported side effects, although certain single nucleotide polymorphisms (SNPs) might alter treatment response and survival depending on the antifibrotic administered. This study investigated variations in response and outcomes to pirfenidone based on patients-specific genetic profiles.

METHODS

Retrospective clinical data were collected from 56 IPF patients and had blood drawn for DNA extraction between 7/2013 and 3/2016, with the last patient followed until 10/2018. Nine SNPs were selected for pharmacogenetic investigation based on prior associations with IPF treatment outcomes or implications for pirfenidone metabolism. Genetic variants were examined in relation to clinical data and treatment outcomes.

RESULTS

Of the 56 patients, 38 were males (67.85%). The average age of IPF at diagnosis was 66.88 years. At the initiation of pirfenidone, the average percent predicted FVC was 70.7%, and the average DLCO percent predicted was 50.02% (IQR 40-61%). Among the genetic variants tested, the TOLLIP rs5743890 risk allele was significantly associated with improved survival, with increasing pirfenidone duration. This finding was observed with CC or CT genotype carriers but not for those with the TT genotype (p = 0.0457). Similarly, the TGF-B1 rs1800470 risk allele was also significantly associated with improved survival with longer pirfenidone therapy (p = 0.0395), even though it was associated with disease progression.

CONCLUSION

This pilot study suggests that in IPF patients, the TOLLIP rs5743890 genotypes CC and CT, as well as TGF-B1 rs 1800470 may be associated with increased survival when treated with pirfenidone.

Idiopathic pulmonary fibrosis and the role of genetics in the era of precision medicine

Idiopathic pulmonary fibrosis (IPF) is a chronic, rare progressive lung disease, characterized by lung scarring and the irreversible loss of lung function. Two anti-fibrotic drugs, nintedanib and pirfenidone, have been demonstrated to slow down disease progression, although IPF mortality remains a challenge and the patients die after a few years from diagnosis. Rare pathogenic variants in genes that are involved in the surfactant metabolism and telomere maintenance, among others, have a high penetrance and tend to co-segregate with the disease in families. Common recurrent variants in the population with modest effect sizes have been also associated with the disease risk and progression. Genome-wide association studies (GWAS) support at least 23 genetic risk loci, linking the disease pathogenesis with unexpected molecular pathways including cellular adhesion and signaling, wound healing, barrier function, airway clearance, and innate immunity and host defense, besides the surfactant metabolism and telomere biology. As the cost of high-throughput genomic technologies continuously decreases and new technologies and approaches arise, their widespread use by clinicians and researchers is efficiently contributing to a better understanding of the pathogenesis of progressive pulmonary fibrosis. Here we provide an overview of the genetic factors known to be involved in IPF pathogenesis and discuss how they will continue to further advance in this field. We also discuss how genomic technologies could help to further improve IPF diagnosis and prognosis as well as for assessing genetic risk in unaffected relatives. The development and validation of evidence-based guidelines for genetic-based screening of IPF will allow redefining and classifying this disease relying on molecular characteristics and contribute to the implementation of precision medicine approaches.

Pterostilbene prevents LPS-induced early pulmonary fibrosis by suppressing oxidative stress, inflammation and apoptosis in vivo

Early pulmonary fibrosis after acute lung injury leads to poor prognosis and high mortality. Pterostilbene (Pts), a bioactive component in blueberries, possesses anti-inflammatory, antioxidative and antifibrotic properties. However, the effects of Pts on lipopolysaccharide (LPS)-induced pulmonary fibrosis are still unknown. In our study, the Pts group showed lower lung injury and fibrosis scores, and lower levels of hydroxyproline and protein (collagen I and transforming growth factor-β) than the scores and levels in mice treated with LPS. MMP-1 was the degrading enzyme of collagen I and LPS caused the inhibition of MMP-1, disturbing the degradation of collagen. Additionally, Pts remarkably reversed the LPS-induced inhibition of interleukin-10 and the release of tumor necrosis factor-α, interleukin-6 and interleukin-1β. In terms of cellular pathways, Pts treatment ameliorated LPS-activated nuclear factor kappa B (NF-κB) and NOD-like receptor NLRP3 signaling. Besides, LPS-induced low levels of A20 could be activated by Pts. In addition, Pts treatment reversed the high levels of Caspase-3, poly ADP-ribose polymerase (PARP) and Bcl2-associated X protein (Bax) expression and the low levels of B cell lymphoma/lewkmia-2 (Bcl2) that had been induced by LPS. Moreover, oxidative stress is also involved in the pathogenesis of fibrosis. Our findings indicate that LPS injection triggered the production of myeloperoxidase (MPO) and malondialdehyde (MDA) and the depletion of superoxide dismutase (SOD) and glutathione (GSH), and that these effects were notably reversed by treatment with Pts. In addition, Pts induced the dissociation of Kelch-like epichlorohydrin-associated protein-1 (Keap-1) and NF-E2 related factor-2 (Nrf2) and the activation of downstream genes (heme oxygenase-1, NAD(P)H:quinine oxidoreductase, glutamate-cysteine ligase catalytic subunit and glutamate-cysteine ligase modifier). In conclusion, oxidative stress, apoptosis and inflammation are involved in early pulmonary fibrosis and Pts exerts a protective effect by activating Keap-1/Nrf2, inhibiting caspase-dependent A20/NF-κB and NLRP3 signaling pathways.

Human amniotic mesenchymal stem cells alleviate paraquat-induced pulmonary fibrosis in rats by inhibiting the inflammatory response

AIMS

To investigate the therapeutic effects of human amniotic mesenchymal stem cells (hAMSCs) on paraquat (PQ)-induced pulmonary fibrosis in rats and investigate the inflammatory mechanisms.

MAIN METHODS

hAMSCs were identified by morphological, flow cytometry and immunocytochemistry. A pulmonary fibrosis model was induced by administering PQ to rats. The hAMSCs group was treated with hAMSCs after 6 h of PQ poisoning. At 21 days after hAMSCs transplantation, lungs were harvested for H&E, Masson and immunohistochemical staining to evaluate pulmonary histopathology, collagen deposition, CD3+ cell infiltration and hAMSCs colonization. Arterial blood was used for lactic acid analysis and venous blood was used to detect TNF-α, IL-6, and TGF-β1 by ELISA method.

KEY FINDINGS

hAMSCs can improve the lung structure and decrease collagen deposition induced by PQ. The membranes of CD3+ T cell in the PQ group were round and complete, while that in the hAMSCs group rats exhibited punctate or diffuse staining. In addition, the CD3+ cell was decreased by hAMSCs administration, and MAB1281-positive cells were detected in lung of hAMSCs group rats. The survival rate of the hAMSCs group was significantly higher than that of the PQ group at 21 days after injection. TNF-α, IL-6, TGF-β1 and lactic acid were significantly decreased by hAMSCs administration.

SIGNIFICANCE

hAMSCs have a significant therapeutic effect on pulmonary fibrosis induced by acute PQ poisoning and can improve survival rate in rats. Furthermore, hAMSCs administration can improve lung histopathology and reduce collagen deposition by reducing inflammatory CD3+ T cell infiltration, inflammatory cytokine expression and lactic acid levels.

The association between transforming growth factor beta1 polymorphism and susceptibility to pulmonary fibrosis: A meta-analysis (MOOSE compliant)

Although many studies have investigated the association of single nucleotide polymorphisms (SNPs) in transforming growth factor beta1 (TGF-β1) gene with pulmonary fibrosis (PF), but their association is still controversial. To clarify this, we performed a meta-analysis.Studies related to TGF-β1 and PF were retrieved from PubMed, Medline, Embase, Scopus, and Wanfang (up to November 30, 2017). We targeted TGF-β1 SNPs that have been reported by ≥3 studies to be included in the current meta-analysis, resulting in only 1 final SNP (rs1800470). The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated in the models of allele comparison (T vs C), homozygote comparison (TT vs CC), dominant (TT vs TC + CC), recessive (TT + TC vs CC) to evaluate the strength of the associations.A total of 7 case-control studies were included in this meta-analysis. Overall, no significant association between TGF-β1 rs1800470 and PF was found (T vs C: OR [95% CI] = 0.96 [0.80, 1.15]; TT vs CC: 0.87 [0.61, 1.22]; TT vs TC + CC: 0.80 [0.62, 1.04]; TT + TC vs CC: 1.13 [0.83, 1.54]). In subgroup analyses by ethnicity or original disease, no statistically significant association between TGF-β1 rs1800470 polymorphisms and PF was demonstrated.This meta-analysis revealed that TGF-β1 rs1800470 polymorphism was not associated with susceptibility to PF development.

Juglanin suppresses fibrosis and inflammation response caused by LPS in acute lung injury

Acute lung injury in children is a complication showing devastating disorders linked to fibrosis progression and inflammation response. Fibrosis and inflammation response are two markers for acute lung injury. Juglanin is a natural product mainly isolated from green walnut husks of Juglans mandshurica, which isconsidered as the functional composition among a series of compounds. It exhibited effective role in various diseases by inhibiting inflammation response. In our study, the protective effects and anti-inflammatory activity of juglanin were investigated in mice and lung cells treated by lipopolysaccharide (LPS) to reveal the possible mechanism by which juglanin attenuates acute lung injury. The mice were separated into four groups. The mouse model was established with 15 mg/kg LPS injection. Juglanin dramatically reduced the inflammation of cell infiltration. Compared to mice only treated with LPS, LPS-treated mice in the presence of juglanin developed less lung fibrosis with lower levels of α-smooth muscle-actin (α-SMA), collagen type I, collagen type III, and transforming growth factor-β1 (TGF-β1). Additionally, juglanin markedly downregulated inflammatory cytokine secretion and phosphorylated nuclear factor-κB (NF-κB) expression via inhibiting IKKα/IκBα signaling pathway. Our results indicate that juglanin has a protective role in LPS-triggered acute lung injury via suppression of fibrosis and inflammation response by NF-κB signaling pathways inactivation. Thus, juglanin may be a potential candidate as dietary supplement for acute lung injury for children in future.

Tuberculosis and lung damage: from epidemiology to pathophysiology

A past history of pulmonary tuberculosis (TB) is a risk factor for long-term respiratory impairment. Post-TB lung dysfunction often goes unrecognised, despite its relatively high prevalence and its association with reduced quality of life. Importantly, specific host and pathogen factors causing lung impairment remain unclear. Host immune responses probably play a dominant role in lung damage, as excessive inflammation and elevated expression of lung matrix-degrading proteases are common during TB. Variability in host genes that modulate these immune responses may determine the severity of lung impairment, but this hypothesis remains largely untested. In this review, we provide an overview of the epidemiological literature on post-TB lung impairment and link it to data on the pathogenesis of lung injury from the perspective of dysregulated immune responses and immunogenetics.

Host factors driving lung injury in TB likely contribute to variable patterns of pulmonary impairment after TBhttp://ow.ly/a3of30hBsxB

Genetic polymorphism in matrix metalloproteinase-9 and transforming growth factor-β1 and susceptibility to combined pulmonary fibrosis and emphysema in a Chinese population

In this study, we aimed to explore the association of genetic polymorphism in matrix metalloproteinase-9 (MMP-9) and transforming growth factor-β1 (TGF-β1) and the susceptibility to combined pulmonary fibrosis and emphysema (CPFE). We examined the polymorphisms of the MMP-9 C-1562T and TGF-β1 T869C in 38 CPFE patients, 50 pulmonary emphysema patients, and 34 idiopathic pulmonary fibrosis (IPF) patients. The frequencies of polymorphic genotypes in MMP-9 were 78.95% CC and 21.05% CT in CPFE group, 76.0% CC and 24.0% CT in emphysema group, and 100.0% CC in IPF group. There were highly statistically significant increased frequencies of the CT genotype and T allele in CPFE and emphysema groups compared with IPF group (p < 0.05). The frequencies of polymorphic genotypes in TGF-β1 were 2.63% CC, 28.95% CT, 68.42% TT in CPFE group, 4.00% CC, 16.00% CT, 80.00% TT in emphysema group, and 5.88% CC, 41.18% CT, 52.94% TT in IPF group. Significant increases in the TT genotype and T allele frequencies were observed in emphysema group compared with IPF group (p < 0.05). Our study has showed that T allele in MMP-9 (C-1562T) and T allele in TGF-β1 (T869C) are risk factors of pulmonary emphysema. The T allele in MMP-9 (C-1562T) possibly predisposes patients with pulmonary fibrosis to develop emphysema.

Association between occupational dust exposure and prognosis of idiopathic pulmonary fibrosis: a Korean national survey

BACKGROUND

Previous studies have investigated the relationship between occupational and environmental agents and idiopathic pulmonary fibrosis (IPF). However, there have been few studies regarding the prognosis of patients with IPF according to patient occupation.

METHODS

We investigated whether occupational dust exposure was associated with clinically decreased lung function and poor prognosis. The Korean Interstitial Lung Disease Research Group conducted a national survey to evaluate the clinical, physiologic, radiologic, and survival characteristics of patients with IPF. A total of 1,311 patients with IPF were stratified into five groups according to their occupation: (1) unemployed or homemakers (n = 628); (2) farmers, fishers, or ranchers (n = 230); (3) sales or service personnel (n = 131); (4) clerical or professional personnel (n = 151); and (5) specific dust-exposed workers (n = 171).

RESULTS

The mean age of subjects at diagnosis, was 67.5 ± 9.7 years. Current smokers were 336 patients, 435 were exsmokers, and 456 were never smokers. Dust-exposed workers showed early onset of IPF (61.3 ± 8.6 years; P < .001) and a longer duration of symptoms at diagnosis (17.0 ± 28.2 months; P = .004). Aging (P = .001; hazard ratio [HR], 1.034; 95% CI, 1.014-1.054), FVC % predicted at diagnosis (P = .004; HR, 0.984; 95% CI, 0.974-0.995), and dust-exposure occupation (P = .033; HR, 1.813; 95% CI, 1.049-3.133) were associated with mortality.

CONCLUSIONS

These findings indicate that occupational dust may be an aggravating factor associated with a poor prognosis in IPF.

The genetic basis of idiopathic pulmonary fibrosis

Throughout the past decade, there have been substantial advances in understanding the pathogenesis of idiopathic pulmonary fibrosis (IPF). Recently, several large genome-wide association and linkage studies have identified common genetic variants in more than a dozen loci that appear to contribute to IPF risk. In addition, family-based studies have led to the identification of rare genetic variants in genes related to surfactant function and telomere biology, and mechanistic studies suggest pathophysiological derangements associated with these rare genetic variants are also found in sporadic cases of IPF. Current evidence suggests that rather than existing as distinct syndromes, sporadic and familial cases of IPF (familial interstitial pneumonia) probably reflect a continuum of genetic risk. Rapidly evolving bioinformatic and molecular biology techniques, combined with next-generation sequencing technologies, hold great promise for developing a comprehensive, integrated approach to defining the fundamental molecular mechanisms that underlie IPF pathogenesis.

Transforming growth factor beta 1 activation, storage, and signaling pathways in idiopathic pulmonary fibrosis in dogs

BACKGROUND

The pathogenesis of idiopathic pulmonary fibrosis (IPF) in dogs is poorly understood. In human, transforming growth factor β1 (TGF-β1) is considered central in the pathogenesis.

OBJECTIVES

To investigate TGF-β1 pathway in IPF.

ANIMALS

Lung tissues from 12 affected and 11 control dogs. Serum from 16 affected West Highland white Terriers (WHWTs) and healthy dogs from predisposed (13 WHWTs, 12 Scottish Terriers and 13 Bichons Frise) and nonpredisposed breeds (10 Whippets, 10 Belgian shepherds, 8 Labradors).

METHODS

In this prospective study, immunohistochemistry was used to evaluate expression and localization of TGF-β1 protein and proteins involved in TGF-β1 signaling (TGF-β receptor type I and phospho-Smad2/3). Pulmonary expression of TGF-β1 and molecules involved in its storage (latent TGF-β binding proteins [LTBP] 1, 2, and 4), activation (ανβ6 and ανβ8 integrins, thrombospondin-1) and signal inhibition (Smad 7) was analyzed by quantitative reverse transcriptase PCR. Circulating TGF-β1 concentration was measured by ELISA.

RESULTS

In IPF, high level of TGF-β1 protein was found in areas of fibrosis, epithelial cells had strong expression of TGF-β receptor type 1 and phospho-Smad2/3, gene expression was decreased for LTBP 4 (P = .009) and β8 integrin (P < .001) and increased for thrombospondin-1 (P = .016); no difference was seen for Smad7, LTBP1 and 2. Serum TGF-β1 concentration was higher in predisposed compared with nonpredisposed breeds (P < .0001).

CONCLUSIONS AND CLINICAL IMPORTANCE

This study identified an enhanced TGF-β1 signaling activity in IPF. TGF-β1 storage and activation proteins with altered expression represent potential therapeutic targets. Higher circulating TGF-β1 concentration in predisposed breeds might partly explain their susceptibility for IPF.

Mucin 5B promoter polymorphism is associated with susceptibility to interstitial lung diseases in Chinese males

The variation of G>T in the MUC5B promoter (rs35705950) has been associated with idiopathic pulmonary fibrosis (IPF) and familial interstitial pneumonia (FIP) in Caucasians, but no information is available regarding this variant in the Chinese population. We recruited 405 patients with interstitial lung diseases (ILD), including 165 IPF patients and 2043 healthy controls, for genotyping the MUC5B gene in the Chinese population. One hundred three patients with pneumonia and 360 patients with autoimmune diseases (ADs) were recruited as disease controls. Our results indicated that the prevalence of the minor allele (T) of the polymorphism rs35705950 in healthy Chinese subjects was approximately 0.66%, which was lower than that described in the Caucasian population. The frequencies of the T allele were 3.33% and 2.22% in IPF and ILD patients, respectively, and these values were significantly higher than those of healthy controls (P = 0.001, OR = 4.332 for IPF, and P = 0.002, OR = 2.855 for ILD). A stratified analysis showed that this variant in MUC5B associated with the risk for ILD mainly in older male Chinese subjects. No difference was observed between patients with pneumonia, AD patients, and healthy controls.

Pathogenesis of idiopathic pulmonary fibrosis and its clinical implications

Idiopathic pulmonary fibrosis (IPF) is the most common and lethal form of idiopathic interstitial pneumonia. The disease is thought to arise following an aberrant reparative response to recurrent alveolar epithelial cell injury leading to progressive loss of function. The median survival time is 3-5 years from diagnosis. Cigarette smoking, exposure to organic and inorganic dust and genetic factors have been shown to increase the risk of disease, although the cause of IPF remains elusive and its pathogenesis incompletely understood. In the last decade, several clinical trials evaluating novel therapies for IPF have been conducted but the results have been mostly disappointing. Conversely, compounds that target anti-fibrotic and growth factor pathways have been proven effective in slowing functional decline and disease progression. These promising results notwithstanding, truly effective therapeutic strategies will likely require combinations of drugs in order to target the multitude of pathways involved in disease pathogenesis.

Expression and mechanism of BRP-39 in bleomycin-induced pulmonary fibrosis in rat

The purpose of the study was to explore the effects of breast regression protein 39 (BRP-39) in bleomycin-induced pulmonary fibrosis and its mechanism in pulmonary fibrosis by studying change in BRP-39 to provide a novel direction for the treatment of idiopathic pulmonary fibrosis. SPF grade male C57BL/6 rats were randomly divided into three groups, including bleomycin group, bleomycin+ BRP-39 recombinant protein group and control group. HE and Masson staining were applied to test the change in lung tissue after being treated by BRP-39, ELISA was applied to test the expression of TGF-β1 in different groups, and Western blot was used to test the expression of BRP-39 in rat lung tissue. Expression of BRP-39 increased, the fibrosis was obvious, and lung tissue collagen increased in bleomycin-induced pulmonary fibrosis in rat lung tissue. Increasing BRP-39 protein level and intratracheal bleomycin medication to establish pulmonary fibrosis model can aggravate pulmonary fibrosis. Along with the increase in BRP-39 protein level, TGF-β1 expression level also increased in lung tissue. Western blot results showed the expression of BRP-39, and TGF-β1 had the same trend in different groups. BRP-39 has effects in bleomycin-induced rat pulmonary fibrosis. Change in BRP-39 can affect the process of bleomycin-induced pulmonary fibrosis. The mechanism of BRP-3 in pulmonary fibrosis may work by regulating TGF-β1.

Effect of transforming growth factor-β1 on acute lung injury caused by paraquat

In China, and other Asian countries, numerous patients have succumbed to pulmonary fibrosis induced by paquarat poisoning, but the early pathogenesis remains unclear. In this study the effect of cytokine transforming growth factor (TGF)-β1 was observed in early acute paraquat poisoning and examined the mechanism by which paraquat caused early acute lung injury. It was discovered that the rat serum TGF-β1 levels in the paraquat groups were significant higher than that in the control group (P<0.05) and the rat pulmonary TGF-β1 mRNA expression levels were also higher than that in the control group (P<0.05). Histological examination indicated that the rat lung tissue was broad and congested, and had been infiltrated by inflammatory cells. Masson's trichrome staining for collagen showed that the lung tissue appeared fibrotic following paraquat poisoning. Ultramicrostructure observation found that macrophages, red blood cells, lymphocytes and granulocytes infiltrated the alveolar space and there were cytolysosomes in the macrophages. The shape of the type II alveolar epithelial cell nuclei were irregular with karyopyknosis. The heterochromatin migrated to the cell edge and lamellar body vacuolization was also observed. Type I alveolar epithelial cells shrank. In conclusion, the effect of cytokine TGF-β1 on paraquat-induced acute lung tissue injury may be important.

Cytokine gene polymorphisms in idiopathic pulmonary fibrosis

AIM: To characterize cytokine gene polymorphisms in patients with idiopathic pulmonary fibrosis (IPF) compared to healthy controls.

METHODS: Fifty-six IPF patients were involved in the study. The control population consisted of 144 healthy volunteers without history of lung disease. All of the patients were diagnosed with IPF according to the American Thoracic Society/European Respiratory Society consensus statement. Polymorphisms in the interleukin (IL)-1, IL-1, IL-1R, IL-1RA, IL-2, IL-4, IL-6, IL-10, IL-12, tumour necrosis factor, interferon, transforming growth factor, IL-1, IL-2, IL-4 and IL-4RA genes were characterized by polymerase chain reaction with sequence-specific primers. Statistical analysis was performed using the MedCalc statistical software. A Bonferroni correction of significance at an alpha of 0.05 was used for multiple analyses. A corrected P value less than 0.0023 (0.05/22) was considered significant.

RESULTS: We found significant differences in the IL-4 promoter region polymorphisms between IPF patients and controls. Namely, polymorphisms of IL-4 (-590) [computed tomography (CT) in 32 of 56 patients vs 27 of 144 controls; P < 0.0001] and IL-4 (-33) (CT in 25 of 56 patients vs 27 of 144 controls; P = 0.0006) differed between both groups. With regard to haplotypes, we found differences in the frequencies for haplotype 1 of IL-4 (-1098) (-590) (-33) between IPF and controls (TCC in 23 of 56, TTC in 10 of 56, and TTT in 21 of 56 patients vs TCC in 112 of 144, TTC in 0 of 144, and TTT in 32 of 144 controls; P < 0.0001). We did not find significant differences in gene polymorphism frequencies of other cytokines in the IPF group vs the controls.

CONCLUSION: We hypothesize that IL-4 promoter polymorphisms could be involved in the pathogenesis of IPF, likely via enhancement of the T_h2 cytokine milieu with exaggerated fibroproliferative healing.