Hsp90 regulation of fibroblast activation in pulmonary fibrosis

Efficacy of umbelliferone-loaded nanostructured lipid carrier in the management of bleomycin-induced idiopathic pulmonary fibrosis: experimental and network pharmacology insight

Idiopathic pulmonary fibrosis (IPF) is a severe and progressive lung disorder with an average survival rate of 3 to 5 years. IPF presents a significant challenge in clinical management, necessitating novel therapeutic approaches. Nanostructured lipid carriers (NLCs) have proven to be promising vehicles for targeted drug delivery to the lung tissues. This research focuses on formulating and evaluating umbelliferone (UMB)-loaded NLCs for the treatment of IPF. UMB-NLC was formulated using the hot emulsion ultrasonication method and was characterized. The formulation was then tested for its efficacy in a bleomycin-induced IPF mice model. Leukocyte infiltration and interleukin-6 were estimated in the bronchoalveolar lavage fluid (BALF). Various antioxidant activities were also assessed for the formulation, followed by histopathological analysis. Furthermore, an in silico mechanistic approach using network pharmacology was carried out to obtain genes of interest. Particle size analysis revealed a mean size of 174.9 ± 3.66 nm for UMB-NLC, ideal for lung tissue targeting. Zeta potential measurements indicated good stability (-34.3 ± 1.35 mV) for long-term storage. Fourier transform infrared spectroscopy (FTIR) confirmed the successful encapsulation of UMB within the lipid matrix of NLCs. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) demonstrated the amorphous state of UMB-NLC, indicating enhanced solubility and bioavailability. Field emission scanning electron microscopy (FESEM) revealed uniform, spherical particles in the nanometer range. Drug entrapment efficiency (EE%) and loading capacity (DL%) were found to be 85.03 ± 2.36% and 17.01 ± 0.48%, respectively, indicating efficient drug incorporation. In vitro release study showed uniform sustained drug release over 48 h, indicating the potential for prolonged therapeutic effect. In vivo studies using UMB-NLC demonstrated significant improvements in bleomycin-induced IPF. A restoration in body weight and lung/body-weight (L/B) ratio was observed compared to disease controls. BALF analysis revealed reduced leukocyte infiltration and decreased inflammatory cytokine IL-6 levels (**p < 0.01). Biochemical assays showed enhanced antioxidant status and reduced oxidative stress in lung tissues. Hydroxyproline content (HPO, **p < 0.01), malondialdehyde (MDA, ***p < 0.001), and total protein content (**p < 0.01) were significantly reduced, while glutathione (GSH, ***p < 0.001), superoxide dismutase (SOD, **p < 0.01), and catalase (CAT, **p < 0.01) were elevated. Histopathological analysis confirmed the attenuation of lung fibrosis with maintained alveolar architecture and reduced fibrotic deposition. Furthermore, network pharmacology identified UMB targets and IPF-related genes with a Venn diagram, and cytoHubba analysis revealed key hub genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment demonstrated UMB's involvement in IPF-related pathways, highlighting its therapeutic potential. Therefore, UMB-NLC may exhibit promising therapeutic potential in the treatment of IPF, offering targeted drug delivery, enhanced bioavailability, and improved efficacy in alleviating pulmonary inflammation and fibrosis.

An antisense oligonucleotide targeting the heat-shock protein HSPB5 as an innovative therapeutic approach in pulmonary fibrosis

BACKGROUND AND PURPOSE

Idiopathic pulmonary fibrosis (IPF) is a fatal disease characterized by fibroblast activation and abnormal accumulation of extracellular matrix in the lungs. We previously demonstrated the importance of the heat shock protein αB-crystallin (HSPB5) in TGF-β1 profibrotic signalling, which suggests that HSPB5 could be a new therapeutic target for the treatment of IPF. The purpose of this study was thus to develop antisense oligonucleotides targeting HSPB5 and to study their effects on the development of experimental pulmonary fibrosis.

EXPERIMENTAL APPROACH

Specific antisense oligonucleotides (ASO) were designed and screened in vitro, based on their ability to inhibit human and murine HSPB5 expression. The selected ASO22 was characterized in vitro in human fibroblast CCD-19Lu cells and A549 epithelial pulmonary cells, as well as in vivo using a mouse model of bleomycin-induced pulmonary fibrosis.

KEY RESULTS

ASO22 was selected for its capacity to inhibit TGF-β1-induced expression of HSPB5 and additional key markers of fibrosis such as plasminogen activator inhibitor-1, collagen, fibronectin and α-smooth muscle actin in fibroblastic human CCD-19Lu cells as well as plasminogen activator inhibitor-1 and α-smooth muscle actin in pulmonary epithelial A549 cells. Intra-tracheal or intravenous administration of ASO22 in bleomycin-induced pulmonary fibrotic mice decreased HSPB5 expression and reduced fibrosis, as demonstrated by decreased pulmonary remodelling, collagen accumulation and Acta2 and Col1a1 expression.

CONCLUSION AND IMPLICATIONS

Our results suggest that an antisense oligonucleotide strategy targeting HSPB5 could be of interest for the treatment of IPF.

Heat shock protein 90α may serve as a biomarker for mild cognitive impairment in type 2 diabetes mellitus patients without diabetic nephropathy

Aim

Chronic inflammation associated oxidative stress is a key factor in complications of type 2 diabetes mellitus (T2DM), including mild cognitive impairment (MCI), partly associated with cerebrovascular lesions including both macrovascular and microvascular changes, and diabetic nephropathy (DN), a kind of diabetic microvascular complication. Heat shock protein 90α (Hsp90α) is known to play a significant role in inflammation associated oxidative stress and DN. This study aims to explore the role of Hsp90α in MCI and its potential as a diagnostic marker for MCI in T2DM patients.

Methods

We included 119 T2DM patients and analyzed their clinical data, Hsp90α levels, and cognitive scores. The relationships among Hsp90α, cognitive function, and urinary albumin-to-creatinine ratio (UACR) were also examined. Binary logistic regression was used to identify MCI risk factors, and ROC curves assessed Hsp90α's diagnostic value for MCI in patients, with or without DN.

Results

Patients with MCI exhibit worse cognitive function, higher UACR, and elevated Hsp90α levels compared to those without MCI. Increased Hsp90α was linked to lower cognitive scores and was identified as a risk factor for MCI. Patients with DN had a higher rate of MCI and cognitive decline than those without DN, and Hsp90α levels correlated with UACR, a DN marker. In patients without DN, higher Hsp90α was a risk factor for MCI; however, this was not observed in those with DN. An Hsp90α cut-off point of 69.105 ng/mL had a sensitivity of 60.0% and specificity of 91.4% for predicting MCI in patients without DN.

Conclusions

Elevated Hsp90α level is a risk factor for cognitive impairment and may serve as a biomarker for MCI in T2DM patients without DN.

The context-dependent effect of cellular senescence: From embryogenesis and wound healing to aging

Aging is characterized by a steady loss of physiological integrity, leading to impaired function and increased vulnerability to death. Cell senescence is a biological process that progresses with aging and is believed to be a key driver of age-related diseases. Senescence, a hallmark of aging, also demonstrates its beneficial physiological aspects as an anti-cancer, pro-regenerative, homeostatic, and developmental mechanism. A transitory response in which the senescent cells are quickly formed and cleared may promote tissue regeneration and organismal fitness. At the same time, senescence-related secretory phenotypes associated with extended senescence can have devastating effects. The fact that the interaction between senescent cells and their surroundings is very context-dependent may also help to explain this seemingly opposing pleiotropic function. Further, mitochondrial dysfunction is an often-unappreciated hallmark of cellular senescence and figures prominently in multiple feedback loops that induce and maintain the senescent phenotype. This review summarizes the mechanism of cellular senescence and the significance of acute senescence. We concisely introduced the context-dependent role of senescent cells and SASP, aspects of mitochondrial biology altered in the senescent cells, and their impact on the senescent phenotype. Finally, we conclude with recent therapeutic advancements targeting cellular senescence, focusing on acute injuries and age-associated diseases. Collectively, these insights provide a future roadmap for the role of senescence in organismal fitness and life span extension.

[Targeting the TGF-β pathway in pulmonary fibrosis: Is it still a relevant strategy?]

Idiopathic pulmonary fibrosis (IPF) is a rare, progressive and fatal disease without pharmacologic curative treatments for the patients. TGF-β is a crucial cytokine in the fibrotic process, and its intracellular signaling pathways are complex and rely on the activation of its receptor. This review summarizes our knowledge on the regulatory checkpoints of the TGF-β signaling. In addition, the main strategies and key potential therapeutic targets identified over recent years are presented, with particular emphasis laid on how they can be used to develop new treatments for pulmonary fibrosis.

Identification of glycolysis-related gene signatures for prognosis and therapeutic targeting in idiopathic pulmonary fibrosis

Background

Glycolysis plays a crucial role in fibrosis, but the specific genes involved in glycolysis in idiopathic pulmonary fibrosis (IPF) are not well understood.

Methods

Three IPF gene expression datasets were obtained from the Gene Expression Omnibus (GEO), while glycolysis-related genes were retrieved from the Molecular Signatures Database (MsigDB). Differentially expressed glycolysis-related genes (DEGRGs) were identified using the "limma" R package. Diagnostic glycolysis-related genes (GRGs) were selected through least absolute shrinkage and selection operator (LASSO) regression regression and support vector machine-recursive feature elimination (SVM-RFE). A prognostic signature was developed using LASSO regression, and time-dependent receiver operating characteristic (ROC) curves were generated to evaluate predictive performance. Single-cell RNA sequencing (scRNA-seq) data were analyzed to examine GRG expression across various cell types. Immune infiltration analysis, Gene Set Enrichment Analysis (GSEA), and Gene Set Variation Analysis (GSVA) were performed to elucidate potential molecular mechanisms. A bleomycin (BLM)-induced pulmonary fibrosis mouse model was used for experimental validation via reverse transcription-quantitative polymerase chain reaction (RT-qPCR).

Results

14 GRGs (VCAN, MERTK, FBP2, TPBG, SDC1, AURKA, ARTN, PGP, PLOD2, PKLR, PFKM, DEPDC1, AGRN, CXCR4) were identified as diagnostic markers for IPF, with seven (ARTN, AURKA, DEPDC1, FBP2, MERTK, PFKM, SDC1) forming a prognostic model demonstrating predictive power (AUC: 0.831-0.793). scRNA-seq revealed cell-type-specific GRG expression, particularly in macrophages and fibroblasts. Immune infiltration analysis linked GRGs to imbalanced immune responses. Experimental validation in a bleomycin-induced fibrosis model confirmed the upregulation of GRGs (such as AURKA, CXCR4). Drug prediction identified inhibitors (such as Tozasertib for AURKA, Plerixafor for CXCR4) as potential therapeutic agents.

Conclusion

This study identifies GRGs as potential prognostic biomarkers for IPF and highlights their role in modulating immune responses within the fibrotic lung microenvironment. Notably, AURKA, MERTK, and CXCR4 were associated with pathways linked to fibrosis progression and represent potential therapeutic targets. Our findings provide insights into metabolic reprogramming in IPF and suggest that targeting glycolysis-related pathways may offer novel pharmacological strategies for antifibrotic therapy.

Combination of HSP90 Inhibitors and HSP70 Inducers Prevent Hydrochloric Acid-Induced Pulmonary Fibrosis in Rabbits

Combined therapies with Heat Shock Protein 90 (HSP90) inhibitors and Heat Shock Protein 70 (HSP70) inducers are gaining significant interest in cancer and cardiovascular research. Here, we tested the hypothesis that HSP90 inhibitors and HSP70 inducers, together, can block the development of pulmonary fibrosis. We exposed New Zealand White Rabbits to hydrochloric acid (HCl, 0.1 N, 1.5 mL/kg), one of the top five chemicals most commonly involved in accidental exposures and inhalation injuries worldwide, and treated animals with either the orally available HSP90 inhibitor TAS-116 (1.7 mg/kg 5x/week) or TAS-116 combined with the HSP70 inducer, geranylgeranyl acetone (GGA, 50 mg/kg, 3x/week). At 60 days post-HCl instillation, TAS and GGA treatment markedly reduced the degree of pulmonary fibrosis, lung dysfunction, and activation of profibrotic pathways. The use of HSP70 inducers may be a helpful tool to improve the profile of HSP90 inhibitors and reduce their minimal effective dose and side effects. Further investigation is required to explore the exact synergistic mechanism behind the antifibrotic profile of HSP90 inhibitors and HSP70 inducers.

The role of heat shock protein 90 in idiopathic pulmonary fibrosis: state of the art

Heat shock protein 90 (HSP 90) and its isoforms are a group of homodimeric proteins that regulate several cellular processes, such as the elimination of misfolded proteins, cell development and post-translational modifications of kinase proteins and receptors. Due to its involvement in extracellular matrix (ECM) remodelling, myofibroblast differentiation and apoptosis, HSP 90 has been investigated as a key player in the pathogenesis of lung fibrosis. Idiopathic pulmonary fibrosis (IPF) is the most common and deadly interstitial lung disease, due to the progressive distortion of lung parenchyma related to the overproduction and deposition of altered ECM, driven by transforming growth factor-β (TGF-β) dependent and independent pathways. The inhibition or induction of HSP 90 is associated with a reduced or increased expression of TGF-β receptors, respectively, suggesting a role for HSP 90 as a biomarker and therapeutic target in IPF. Experimental drugs such as geldanamycin and its derivatives 17-AAG (17-N-allylamino-17-demethoxygeldanamicin) and 17-DMAG (17-dimethylaminoethylamino-17-demethoxigeldanamycin), along with AUY-922, 1G6-D7, AT-13387, TAS-116 and myricetin, have been found to reduce lung fibrosis in both in vivo and in vitro models, supporting the role of this emerging target. This review aims to illustrate the structure and biological function of HSP 90 in the context of IPF pathobiology, as well as perspective application of this molecule as a biomarker and therapeutic target for IPF.

Cell Membrane Hybrid Liposome-Targeted Delivery of the Heat Shock Protein 90 C-Terminal Inhibitor for the Treatment of Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) represents a grave challenge as it is characterized by high fatality rates and irreversible progression without effective clinical interventions available at present. Previous studies have demonstrated that inhibition of heat shock protein 90 (HSP90) by an N-terminal inhibitor disrupts its interaction with TGFβRII, leading to the instability of TGFβRII, thus blocking the role of transforming growth factor-β1 (TGF-β1), which could potentially ameliorate IPF symptoms. However, given that the broad spectrum of HSP90 N-terminal inhibitors may lead to unanticipated side effects, we hypothesize that C-terminal inhibitors of HSP90 can interfere with TGFβRII while minimizing adverse reactions. In this study, silybin, a C-terminal inhibitor of HSP90, was separated into monomers, and silybin A was screened for its superior efficacy against TGFβRII. To facilitate targeted therapy for treating IPF, a cell membrane hybrid liposome loaded with silybin A (Cm-A-Lip) was developed to deliver silybin A to lung fibroblasts through pulmonary drug delivery. A bleomycin-induced IPF mouse model was used to evaluate the efficacy of Cm-A-Lip. By examination of lung hydroxyproline content, wet weight, histology, and inflammatory factor expression, the results showed that pulmonary delivery of Cm-A-Lip could increase the drug retention time in lung tissue compared with intravenous injection. Furthermore, Cm-A-Lip exhibited superior antifibrotic activity relative to conventional liposmomes loaded with silybin A (A-Lip) while concurrently mitigating systemic inflammatory responses associated with silybin A administration, thus enhancing the overall safety profile.

Binding with HSP90β, cimifugin ameliorates fibrotic cataracts in vitro and in vivo by inhibiting TGFβ signaling pathways

Fibrotic cataracts, the most frequent complications after phacoemulsification, cannot be cured by drugs in clinic. The primary mechanism underlying the disease is the epithelial-mesenchymal transition (EMT). Cimifugin is a natural monomer component of traditional Chinese medicines. Previous researches have demonstrated the effect of cimifugin inhibiting EMT in the lung. The purpose of this work is to evaluate the impact of cimifugin on EMT in the lens and elucidate its precise mechanism. The pathogenesis of fibrotic cataracts was simulated using TGFβ2-induced cell model of EMT and the injury-induced anterior subcapsular cataract animal model. Through H&E staining and immunofluorescence of mice eyeballs, we discovered that cimifugin can inhibit the expansion of fibrotic lesions in vivo. Furthermore, at mRNA and protein levels, we confirmed that cimifugin can allay EMT of lens epithelial cells (LECs) in vitro and in vivo. Additionally, the inhibition of cimifugin on the activation of TGFβ-related signaling pathways was certified by immunoblot. HSP90β, the target of cimifugin, was predicted by network pharmacology and verified by drug affinity responsive target stability, the cellular thermal shift assay, and microscale thermophoresis. Moreover, co-immunoprecipitation revealed the interaction between HSP90β and TGFβ receptor (TGFβR) II. Together, our findings showed that by weakening the binding of HSP90β and TGFβRII, cimifugin suppressed the TGFβ signaling pathways to alleviate fibrotic cataracts. Cimifugin is a promising medication for the treatment of fibrotic cataracts.

Lung Single-Cell Transcriptomics Offers Insights into the Pulmonary Interstitial Toxicity Caused by Silica Nanoparticles

The adverse respiratory outcomes motivated by silica nanoparticles (SiNPs) exposure have received increasing attention. Herein, we aim to elucidate the interplay of diverse cell populations in the lungs and key contributors in triggering lung injuries caused by SiNPs. We conducted a subchronic respiratory exposure model of SiNPs via intratracheal instillation in Wistar rats, where rats were administered with 1.5, 3.0, or 6.0 mg/kg body weight SiNPs once a week for 12 times in total. We revealed that SiNPs caused pulmonary interstitial injury in rats by histopathological examination and pulmonary hydroxyproline determination. Further, a single-cell RNA-Seq via screening 10 457 cells in the rat lungs disclosed cell-specific responses to SiNPs and cell-to-cell interactions within the alveolar macrophages, epithelial cells, and fibroblasts from rat lungs. These disturbed responses were principally related to the dysregulation of protein homeostasis (proteostasis), accompanied by an inflammatory response in macrophages, cell death in epithelial, proliferation, and extracellular matrix deposition in fibroblast. These cell-specific responses may serve a synergistic role in the pathogenesis of pulmonary interstitial disease triggered by SiNPs. In particular, the analyses of gene interaction networks and gene-disease associations filtered out heat shock proteins (Hsps) family genes crucial to the observed pulmonary lesions caused by SiNPs. Of note, both GEO database analysis and our experiments' validation indicated that Hsps, especially Hspd1, may be a key contributor to pulmonary interstitial injury, possibly through triggering oxidative stress, immune response, and disrupting protein homeostasis. Taken together, our study provides insights into pulmonary toxic effects and underlying molecular mechanisms of SiNPs from a single-cell perspective.

Silencing METTL3 Increases HSP70 Expression and Alleviates Fibrosis in Keratocytes

Purpose

To explore the potential role of N6-methyladenosine (m6A) and its regulatory factors in corneal fibrosis response using both in vivo and in vitro models.

Methods

This study utilized the C57BL/6 mouse corneal alkali burn as an in vivo model and stimulated keratocytes with transforming growth factor beta 1 (TGF-β1) in vitro. Small interfering RNA (siRNA) was employed to downregulate the expression of YTH domain family member 2 (YTHDF2), methyltransferase-like 3 (METTL3), and fat mass and obesity-associated protein (FTO) in keratocytes. The expression of relevant genes was quantified by real-time quantitative reverse-transcription PCR (qRT-PCR), western blotting, and immunohistochemistry.

Results

After an alkali burn, m6A modification in corneas increased, with the most notable increase observed on the fourth day after the injury. The levels of METTL3 and FTO initially decreased and then increased. After 21 days following an alkali burn, the corneal fibrosis was most significant. The levels of METTL3 and FTO were elevated. There were higher levels in m6A modification and the expression of METTL3 and FTO in keratocytes stimulated by TGF-β1. In corneas after alkali burns and in keratocytes stimulated by TGF-β1, the expression of heat shock protein 70 (HSP70) was negatively correlated with fibrotic response markers. Silencing METTL3 and YTHDF2 in keratocytes increased HSP70 expression and reduced the expression of fibrosis-related indicators in keratocytes stimulated by TGF-β1. However, silencing FTO did not significantly affect the expression of HSP70 and fibrosis.

Conclusions

These findings indicate that METTL3 is involved in the modulation of corneal fibrosis through the regulation of HSP70 expression in a manner that is dependent on YTHDF2.

A novel Non-rodent animal model of hydrochloric acid-induced acute and chronic lung injury

Hydrochloric acid is one of the most prevalent and hazardous chemicals. Accidental spills occur in industrial plants or during transportation. Exposure to HCl can induce severe health impairment, including acute and chronic pulmonary diseases. We have previously described the molecular, structural, and functional aspects of the development of chronic lung injury and pulmonary fibrosis caused by intratracheal instillation of HCl in mice. Although mouse models of human disease have many advantages, rodents are evolutionary far from human and exhibit significant anatomical and physiological differences. Genetic and anatomic similarities between rabbits and humans are significantly higher. Rabbit models of HCl-induced lung injury have been used sparsely to evaluate acute lung injury. In this study, for the first time, we utilized rabbits as a model of HCl-induced pulmonary fibrosis and chronic lung injury. We present molecular, histological, and functional evidence that demonstrate the utility of using this model for studying new pharmaceutics against pulmonary fibrosis.

LRG1 loss effectively restrains glomerular TGF-β signaling to attenuate diabetic kidney disease

Transforming growth factor (TGF)-β signaling is a well-established pathogenic mediator of diabetic kidney disease (DKD). However, owing to its pleiotropic actions, its systemic blockade is not therapeutically optimal. The expression of TGF-β signaling regulators can substantially influence TGF-β's effects in a cell- or context-specific manner. Among these, leucine-rich α2-glycoprotein 1 (LRG1) is significantly increased in glomerular endothelial cells (GECs) in DKD. As LRG1 is a secreted molecule that can exert autocrine and paracrine effects, we examined the effects of LRG1 loss in kidney cells in diabetic OVE26 mice by single-cell transcriptomic analysis. Gene expression analysis confirmed a predominant expression of Lrg1 in GECs, which further increased in diabetic kidneys. Loss of Lrg1 led to the reversal of angiogenic and TGF-β-induced gene expression in GECs, which were associated with DKD attenuation. Notably, Lrg1 loss also mitigated the increased TGF-β-mediated gene expression in both podocytes and mesangial cells in diabetic mice, indicating that GEC-derived LRG1 potentiates TGF-β signaling in glomerular cells in an autocrine and paracrine manner. Indeed, a significant reduction in phospho-Smad proteins was observed in the glomerular cells of OVE26 mice with LRG1 loss. These results indicate that specific antagonisms of LRG1 may be an effective approach to curb the hyperactive glomerular TGF-β signaling to attenuate DKD.

A Novel Non-Rodent Animal Model of Hydrochloric Acid-Induced acute and chronic lung injury

Hydrochloric acid is one of the most prevalent and dangerous chemicals. Accidental spills occur in industrial plants or during transportation. Exposure to HCl can induce severe health impairment, including acute and chronic pulmonary diseases. We have previously described the molecular, structural, and functional aspects of the development of chronic lung injury and pulmonary fibrosis caused by intratracheal instillation of HCl in mice. Although mouse models of human disease have many advantages, rodents are evolutionary far from human and exhibit significant anatomical and physiological differences. Genetic and anatomic similarities between rabbits and humans are significantly higher. Rabbit models of HCl-induced lung injury have been used sparsely to evaluate acute lung injury. In this study, for the first time, we utilized rabbits as a model of HCl-induced pulmonary fibrosis and chronic lung injury. We present molecular, histological, and functional evidence that demonstrate the utility of using this model for studying new pharmaceutics against pulmonary fibrosis.

Humanized L184Q Mutated Surfactant Protein C Gene Alters Alveolar Type 2 Epithelial Cell Fate

Alveolar type 2 epithelial (AT2) cells synthesize surfactant protein C (SPC) and repair an injured alveolar epithelium. A mutated surfactant protein C gene (SftpcL184Q, Gene ID: 6440) in newborns has been associated with respiratory distress syndrome and pulmonary fibrosis. However, the underlying mechanisms causing Sftpc gene mutations to regulate AT2 lineage remain unclear. We utilized three-dimensional (3D) feeder-free AT2 organoids in vitro to simulate the alveolar epithelium and compared AT2 lineage characteristics between WT (C57BL/6) and SftpcL184Q mutant mice using colony formation assays, immunofluorescence, flow cytometry, qRT-PCR, and Western blot assays. The AT2 numbers were reduced significantly in SftpcL184Q mice. Organoid numbers and colony-forming efficiency were significantly attenuated in the 3D cultures of primary SftpcL184Q AT2 cells compared to those of WT mice. Podoplanin (PDPN, Alveolar type 1 cell (AT1) marker) expression and transient cell count was significantly increased in SftpcL184Q organoids compared to in the WT mice. The expression levels of CD74, heat shock protein 90 (HSP90), and ribosomal protein S3A1 (RPS3A1) were not significantly different between WT and SftpcL184Q AT2 cells. This study demonstrated that humanized SftpcL184Q mutation regulates AT2 lineage intrinsically. This regulation is independent of CD74, HSP90, and RPS3A1 pathways.

Comprehensive review of potential drugs with anti-pulmonary fibrosis properties

Pulmonary fibrosis is a chronic and progressive lung disease characterized by the accumulation of scar tissue in the lungs, which leads to impaired lung function and reduced quality of life. The prognosis for idiopathic pulmonary fibrosis (IPF), which is the most common form of pulmonary fibrosis, is generally poor. The median survival for patients with IPF is estimated to be around 3-5 years from the time of diagnosis. Currently, there are two approved drugs (Pirfenidone and Nintedanib) for the treatment of IPF. However, Pirfenidone and Nintedanib are not able to reverse or cure pulmonary fibrosis. There is a need for new pharmacological interventions that can slow or halt disease progression and cure pulmonary fibrosis. This review aims to provide an updated overview of current and future drug interventions for idiopathic pulmonary fibrosis, and to summarize possible targets of potential anti-pulmonary fibrosis drugs, providing theoretical support for further clinical combination therapy or the development of new drugs.

Senolytics: from pharmacological inhibitors to immunotherapies, a promising future for patients' treatment

The involvement of cellular senescence in the initiation and propagation of diseases is clearly characterized, making the elimination of senescent cells essential to treat age-related diseases. The development of senolytic drugs demonstrated that targeting these cells limits the deterioration of patients' condition, by inducing apoptosis. Nevertheless, the first generations of senolytics which has been developed displayed their activities through specific mechanisms and demonstrated several limitations during clinical development. However, the rational to eliminate senescent cells remains evident, with the necessity to develop specific therapies in a context of diseases and tissues. The evolutions in the field of drug discovery open the way to a new generation of senolytic therapies, such as immunological approaches (CAR-T cells, Antibody-Drug Conjugated or vaccines), which require preliminary steps of research to identify markers specifically expressed on senescent cells, demonstrating promising specific effects. Currently, the preclinical development of these strategies appears more challenging to avoid strong side effects, but the expected results are commensurate with patients' hopes for treatments. In this review, we highlight the fact that the classical senolytic approach based on drug repurposing display limited efficacy and probably reached its limits in term of clinical development. The recent development of more complex therapies and the extension of interest in the domain of senescence in different fields of research allow to extend the possibility to discover powerful therapies. The future of age-related diseases treatment is linked to the development of new approaches based on cell therapy or immunotherapy to offer the best treatment for patients.

HSP70 Is a Critical Regulator of HSP90 Inhibitor's Effectiveness in Preventing HCl-Induced Chronic Lung Injury and Pulmonary Fibrosis

Exposure to hydrochloric acid (HCl) can provoke acute and chronic lung injury. Because of its extensive production for industrial use, frequent accidental exposures occur, making HCl one of the top five chemicals causing inhalation injuries. There are no Food and Drug Administration (FDA)-approved treatments for HCl exposure. Heat shock protein 90 (HSP90) inhibitors modulate transforming growth factor-β (TGF-β) signaling and the development of chemical-induced pulmonary fibrosis. However, little is known on the role of Heat Shock Protein 70 (HSP70) during injury and treatment with HSP90 inhibitors. We hypothesized that administration of geranylgeranyl-acetone (GGA), an HSP70 inducer, or gefitinib (GFT), an HSP70 suppressant, alone or in combination with the HSP90 inhibitor, TAS-116, would improve or worsen, respectively, HCl-induced chronic lung injury in vivo and endothelial barrier dysfunction in vitro. GGA, alone, improved HCl-induced human lung microvascular endothelial cells (HLMVEC) barrier dysfunction and, in combination with TAS-116, improved the protective effect of TAS-116. In mice, GGA reduced HCl toxicity and while TAS-116 alone blocked HCl-induced chronic lung injury, co-administration with GGA, resulted in further improvement. Conversely, GFT potentiated HCl-induced barrier dysfunction and impaired the antidotal effects of TAS-116. We conclude that combined treatments with HSP90 inhibitors and HSP70 inducers may represent a novel therapeutic approach to manage HCl-induced chronic lung injury and pulmonary fibrosis.

Cavin-2 promotes fibroblast-to-myofibroblast trans-differentiation and aggravates cardiac fibrosis

AIMS

Transforming growth factor β (TGF-β) signalling is one of the critical pathways in fibroblast activation, and several drugs targeting the TGF-β/Smad signalling pathway in heart failure with cardiac fibrosis are being tested in clinical trials. Some caveolins and cavins, which are components of caveolae on the plasma membrane, are known for their association with the regulation of TGF-β signalling. Cavin-2 is particularly abundant in fibroblasts; however, the detailed association between Cavin-2 and cardiac fibrosis is still unclear. We tried to clarify the involvement and role of Cavin-2 in fibroblasts and cardiac fibrosis.

METHODS AND RESULTS

To clarify the role of Cavin-2 in cardiac fibrosis, we performed transverse aortic constriction (TAC) operations on four types of mice: wild-type (WT), Cavin-2 null (Cavin-2 KO), Cavin-2flox/flox , and activated fibroblast-specific Cavin-2 conditional knockout (Postn-Cre/Cavin-2flox/flox , Cavin-2 cKO) mice. We collected mouse embryonic fibroblasts (MEFs) from WT and Cavin-2 KO mice and investigated the effect of Cavin-2 in fibroblast trans-differentiation into myofibroblasts and associated TGF-β signalling. Four weeks after TAC, cardiac fibrotic areas in both the Cavin-2 KO and the Cavin-2 cKO mice were significantly decreased compared with each control group (WT 8.04 ± 1.58% vs. Cavin-2 KO 0.40 ± 0.03%, P < 0.01; Cavin-2flox/flox , 7.19 ± 0.50% vs. Cavin-2 cKO 0.88 ± 0.44%, P < 0.01). Fibrosis-associated mRNA expression (Col1a1, Ctgf, and Col3) was significantly attenuated in the Cavin-2 KO mice after TAC. α1 type I collagen deposition and non-vascular αSMA-positive cells (WT 43.5 ± 2.4% vs. Cavin-2 KO 25.4 ± 3.2%, P < 0.01) were reduced in the heart of the Cavin-2 cKO mice after TAC operation. The levels of αSMA protein (0.36-fold, P < 0.05) and fibrosis-associated mRNA expression (Col1a1, 0.69-fold, P < 0.01; Ctgf, 0.27-fold, P < 0.01; Col3, 0.60-fold, P < 0.01) were decreased in the Cavin-2 KO MEFs compared with the WT MEFs. On the other hand, αSMA protein levels were higher in the Cavin-2 overexpressed MEFs compared with the control MEFs (2.40-fold, P < 0.01). TGF-β1-induced Smad2 phosphorylation was attenuated in the Cavin-2 KO MEFs compared with WT MEFs (0.60-fold, P < 0.01). Heat shock protein 90 protein levels were significantly reduced in the Cavin-2 KO MEFs compared with the WT MEFs (0.69-fold, P < 0.01).

CONCLUSIONS

Cavin-2 loss suppressed fibroblast trans-differentiation into myofibroblasts through the TGF-β/Smad signalling. The loss of Cavin-2 in cardiac fibroblasts suppresses cardiac fibrosis and may maintain cardiac function.

Fibroblast-derived extracellular vesicles as trackable efficient transporters of an experimental nanodrug with fibrotic heart and lung targeting

The discovery of extracellular vesicles (EVs) as efficient exogenous biotransporters of therapeutic agents into cells across biological membranes is an exciting emerging field. Especially the potential of EVs as targeted delivery systems for diseases with selective treatments, such as fibrosis, whose treatment causes side effects in other organs not involved in the disease. Methods: In this study, we collected embryonic fibroblast-derived EVs from two different centrifugation fractions, 10 K g and 100 K g fractions from a NIH-3T3 cell line loaded with an experimental drug. Mice with fibrotic hearts and lungs were obtained by administration of angiotensin II. We generated fluorescent EVs and bioluminescent drug to observe their accumulation by colocalization of their signals in fibrotic heart and lung. The biodistribution of the drug in various organs was obtained by detecting the Au present in the drug nanostructure. Results: The drug-loaded EVs successfully reduced fibrosis in pathological fibroblasts in vitro, and modified the biodistribution of the experimental drug, enabling it to reach the target organs in vivo. We described the pre-analytical characteristics of EVs related to physical variables, culture and harvesting conditions, crucial for their in vivo application as nanotransporters using a previously validated protein-based antifibrotic drug. The results showed the colocalization of EVs and the experimental drug in vivo and ex vivo and the efficient reduction of fibrosis in vitro. This work demonstrates that 10K-EVs and 100K-EVs derived from fibroblasts can act as effective biotransporters for targeted drug delivery to profibrotic fibroblasts, lungs, or heart. Conclusion: We observed that fibroblast-derived 10K-EVs and 100K-EVs are useful biotransporters encapsulating a new generation drug leading to a reduction of fibrosis in profibrotic fibroblasts in vitro. In addition, drug containing EVs were shown to reach fibrotic heart and lungs in vivo, enhancing free drug biodistribution.

Mutations F352A and Y528A in human HSP90α reduce fibronectin association and fibrillogenesis in cell-derived matrices

HSP90 is a ubiquitously expressed chaperone protein that regulates the maturation of numerous substrate proteins called 'clients'. The glycoprotein fibronectin (FN) is an important protein of the extracellular matrix (ECM) and a client protein of HSP90. FN and HSP90 interact directly, and the FN ECM is regulated by exogenous HSP90 or HSP90 inhibitors. Here, we extend the analysis of the HSP90 - FN interaction. The importance of the N-terminal 70-kDa fragment of fibronectin (FN70) and FN type I repeat was demonstrated by competition for FN binding between HSP90 and the functional upstream domain (FUD) of the Streptococcus pyogenes F1 adhesin protein. Furthermore, His-HSP90α mutations F352A and Y528A (alone and in combination) reduced the association with full-length FN (FN-FL) and FN70 in vitro. Unlike wild type His-HSP90α, these HSP90 mutants did not enhance FN matrix assembly in the Hs578T cell line model when added exogenously. Interestingly, the HSP90 E353A mutation, which did not significantly reduce the HSP90 - FN interaction in vitro, dramatically blocked FN matrix assembly in Hs578T cell-derived matrices. Taken together, these data extend our understanding of the role of HSP90 in FN fibrillogenesis and suggest that promotion of FN ECM assembly by HSP90 is not solely regulated by the affinity of the direct interaction between HSP90 and FN.

Nε-Carboxymethyl-Lysine Modification of Extracellular Matrix Proteins Augments Fibroblast Activation

The extracellular matrix (ECM) is a dynamic complex protein network that provides structural integrity and plays an active role in shaping fibroblast behavior both in health and disease. Despite its essential functions, the impact of age-associated post-translational modifications on ECM-driven fibroblast activities such as proliferation, survival, fibroblast-to-myofibroblast transformation (FMT), and extracellular matrix production remains largely unknown. Nε-carboxymethyl-lysine (CML) is one of the well-characterized advanced glycation end-products (AGEs) that can occur on lysine residues within ECM proteins through non-enzymatic glycation. In this study, we determined the accumulation and the effects of the CML-modified ECM (CML-ECM) on fibroblast activation. Immunostainings and immunoblot analysis demonstrated significant increases in CML-AGE content in idiopathic pulmonary fibrosis (IPF) compared to age-matched healthy lungs. Gene expression analysis and fibroblast activation assays collectively implicate the ECM as a negative regulator of fibroblast activation. Notably, the CML modification of the ECM resulted in a significant decrease in its anti-fibrotic effects including proliferation, FMT, apoptosis, and ECM production. Together, the results of this study revealed an unexplored pathological role played by the CML-ECM on fibroblast activation, which has wide implications in IPF and other fibrotic diseases.

STA9090 as a Potential Therapeutic Agent for Liver Fibrosis by Modulating the HSP90/TβRII/Proteasome Interplay: Novel Insights from In Vitro and In Vivo Investigations

Liver fibrosis is a progressive condition characterized by the build-up of fibrous tissue resulting from long-term liver injury. Although there have been advancements in research and treatment, there is still a need for effective antifibrotic medication. HSP90 plays a crucial role in the development of fibrosis. It acts as a molecular chaperone that assists in the proper folding and stability of TβRII, potentially regulating the signaling of TGF-β1. It has been established that TβRII can be degraded through the proteasome degradation system, either via ubiquitination-dependent or -independent pathways. In the present study, STA9090 demonstrated promising effects in both in vitro and in vivo models. It reduced LDH leakage, prolonged the survival rate of hepatocytes in rats with liver fibrosis, and improved liver function. Importantly, STA9090 exerted pleiotropic effects by targeting proteins involved in limiting collagen production, which resulted in improved microscopic features of the rat livers. Our findings suggest that STA9090-induced inhibition of HSP90 leads to the degradation of TβRII, a fibrogenic client protein of HSP90, through the activation of the 20S proteasomal degradation system. We also revealed that this degradation mechanism is not dependent on the autophagy-lysosomal pathway. Additionally, STA9090 was found to destabilize HIF-1α and facilitate its degradation, leading to the reduced transcription of VEGF. Moreover, STA9090's ability to deactivate the NFκB signaling pathway highlights its potential as an anti-inflammatory and antifibrotic agent. However, further research is necessary to fully elucidate the underlying mechanisms and fully capitalize on the therapeutic benefits of targeting HSP90 and associated pathways.

Neotuberostemonine and tuberostemonine ameliorate pulmonary fibrosis through suppressing TGF-β and SDF-1 secreted by macrophages and fibroblasts via the PI3K-dependent AKT and ERK pathways

Activated fibroblasts and M2-polarized macrophages may contribute to the progression of pulmonary fibrosis by forming a positive feedback loop. This study was aimed to investigate whether fibroblasts and macrophages form this loop by secreting SDF-1 and TGF-β and the impacts of neotuberostemonine (NTS) and tuberostemonine (TS). Mice were intratracheally injected with 3 U·kg^-1 bleomycin and orally administered with 30 mg·kg^-1 NTS or TS. Primary pulmonary fibroblasts (PFBs) and MH-S cells (alveolar macrophages) were used in vitro. The animal experiments showed that NTS and TS improved fibrosis related indicators, inhibited fibroblast activation and macrophage M2 polarization, and reduced the levels of TGF-β and SDF-1 in alveolar lavage fluid. Cell experiments showed that TGF-β1 may activated fibroblasts into myofibroblasts secreting SDF-1 by activating the PI3K/AKT/HIF-1α and PI3K/PAK/RAF/ERK/HIF-1α pathways. It was also found for the first time that SDF-1 was able to directly polarize macrophages into M2 phenotype secreting TGF-β through the same pathways as mentioned above. Moreover, the results of the cell coculture confirmed that fibroblasts and macrophages actually developed a feedback loop to promote fibrosis, and the secretion of TGF-β and SDF-1 was crucial for maintaining this loop. NTS and TS may disturb this loop through inhibiting both the PI3K/AKT/HIF-1α and PI3K/PAK/RAF/ERK/HIF-1α pathways to improve pulmonary fibrosis. NTS and TS are stereoisomeric alkaloids with pyrrole[1,2-a]azapine skeleton, and their effect on improving pulmonary fibrosis may be largely attributed to their parent nucleus. Moreover, this study found that inhibition of both the AKT and ERK pathways is essential for maximizing the improvement of pulmonary fibrosis.

Inhibiting Heat Shock Protein 90 Attenuates Nucleus Pulposus Fibrosis and Pathologic Angiogenesis Induced by Macrophages via Down-Regulating Cell Migration-Inducing Protein

Intervertebral disc (IVD) degeneration (IVDD) is usually accompanied by nucleus pulposus (NP) fibrosis and pathologic angiogenesis, which are possibly associated with macrophage infiltration. Previous research indicates a destructive role of macrophages and the protective effect of inhibiting heat shock protein 90 (HSP90) in IVDD. Herein, the effects of inhibiting HSP90 on NP fibrosis and pathologic angiogenesis induced by macrophages were investigated further. Single-cell RNA-sequencing analysis was used to classify fibrotic NP cell (NPC) clusters and healthy NPC clusters in human NP tissues. The fibrotic NPC clusters were possibly associated with angiogenesis-related biological processes. Immunostaining showed the spatial association between blood vessel ingrowth and macrophage infiltration, as well as elevated levels of cell migration-inducing protein (CEMIP) and vascular endothelial growth factor A in severely degenerated human IVD tissues. Particularly, HSP90 inhibitor tanespimycin (17-AAG) ameliorated macrophage-induced fibrotic phenotype of NPCs via inhibiting CEMIP. M2, but not M1, macrophages promoted the pro-angiogenic ability of endothelial cells, which was attenuated by 17-AAG or HSP90 siRNA. Reversing the fibrotic phenotype of NPCs by Cemip siRNA also mitigated the pro-angiogenic effects of M2-conditioned medium-treated NPCs. Moreover, the murine IVDD model supported the 17-AAG-induced amelioration of NP fibrosis and endothelial cell invasion in IVD tissues. In conclusion, inhibiting HSP90 attenuated two interrelated pathologic processes, NP fibrosis and pathologic angiogenesis, induced by macrophages via down-regulating CEMIP.

Role of heparanase in ARDS through autophagy and exosome pathway (review)

Acute respiratory distress syndrome (ARDS) is the most common respiratory disease in ICU. Although there are many treatment and support methods, the mortality rate is still high. The main pathological feature of ARDS is the damage of pulmonary microvascular endothelium and alveolar epithelium caused by inflammatory reaction, which may lead to coagulation system disorder and pulmonary fibrosis. Heparanase (HPA) plays an significant role in inflammation, coagulation, fibrosis. It is reported that HPA degrades a large amount of HS in ARDS, leading to the damage of endothelial glycocalyx and inflammatory factors are released in large quantities. HPA can aggrandize the release of exosomes through syndecan-syntenin-Alix pathway, leading to a series of pathological reactions; at the same time, HPA can cause abnormal expression of autophagy. Therefore, we speculate that HPA promotes the occurrence and development of ARDS through exosomes and autophagy, which leads to a large amount of release of inflammatory factors, coagulation disorder and pulmonary fibrosis. This article mainly describes the mechanism of HPA on ARDS.

Potential biomarkers for diagnosis and disease evaluation of idiopathic pulmonary fibrosis

ABSTRACT

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease characterized by progressive lung fibrogenesis and histological features of usual interstitial pneumonia. IPF has a poor prognosis and presents a spectrum of disease courses ranging from slow evolving disease to rapid deterioration; thus, a differential diagnosis remains challenging. Several biomarkers have been identified to achieve a differential diagnosis; however, comprehensive reviews are lacking. This review summarizes over 100 biomarkers which can be divided into six categories according to their functions: differentially expressed biomarkers in the IPF compared to healthy controls; biomarkers distinguishing IPF from other types of interstitial lung disease; biomarkers differentiating acute exacerbation of IPF from stable disease; biomarkers predicting disease progression; biomarkers related to disease severity; and biomarkers related to treatment. Specimen used for the diagnosis of IPF included serum, bronchoalveolar lavage fluid, lung tissue, and sputum. IPF-specific biomarkers are of great clinical value for the differential diagnosis of IPF. Currently, the physiological measurements used to evaluate the occurrence of acute exacerbation, disease progression, and disease severity have limitations. Combining physiological measurements with biomarkers may increase the accuracy and sensitivity of diagnosis and disease evaluation of IPF. Most biomarkers described in this review are not routinely used in clinical practice. Future large-scale multicenter studies are required to design and validate suitable biomarker panels that have diagnostic utility for IPF.

Benzylisoquinoline alkaloids inhibit lung fibroblast activation mainly via inhibiting TGF-β1/Smads and ERK1/2 pathway proteins

Backgrounds

Liensinine (Lien), Neferine (Nef), Isoliensinine (Iso) and Tetrandrine (Tet), benzylisoquinoline alkaloids (BIAs), have been shown inhibitory effects on pulmonary fibrosis (PF) through anti-inflammatory, anti-oxidative activities, inhibition of cytokines and NF-κB. Effects of other similar BIAs, Dauricine (Dau), Papaverine (Pap) and lotusine (Lot), on PF remain unclear. Here, we explored the effects of five bisbenzylisoquinoline (Lien, Nef, Iso, Tet and Dau) and two monobenzylisoquinoline (Pap, Lot) alkaloids on normal and PF fibroblasts.

Methods

Primary normal and PF lung fibroblasts were cultured and treated with these alkaloids. Proliferation, activation, migration and apoptosis changes were detected by MTT, wound healing assay, flow cytometry. Protein level was analyzed by Western blot.

Results

All BIAs inhibited proliferation of normal and PF lung fibroblasts induced by TGF-β. α-SMA protein level in normal and PF lung fibroblasts decreased after Lien, Nef, Iso, Tet and Dau treatment. Pap and Lot had no influence on α-SMA expression. Dau showed the strongest inhibitory effects on proliferation and activation among alkaloids. The migration rates of normal and PF lung fibroblasts were inhibited by Lien, Nef, Iso, and Dau. Lien, Nef, Iso and Dau significantly promoted apoptosis, while Tet had no effect on apoptosis. Pap and Lot had no influence on activation, migration and apoptosis. Dau significantly inhibited Smad3/4 and p-ERK1/2 protein overexpression induced by TGF-β1.

Conclusions

Bisbenzylisoquinoline alkaloids had stronger effects on inhibiting lung fibroblasts than monobenzylisoquinoline alkaloids. Dau expressed the strongest inhibitory effects, which may be related to its inhibition of TGF-β1/Smad3/4 and p-ERK1/2 pathway proteins.

Network pharmacology and molecular docking combined with widely targeted metabolomics to elucidate the potential compounds and targets of Euphorbia helioscopia seeds for the treatment of pulmonary fibrosis

BACKGROUND

The whole herb of Euphorbia helioscopia has been traditionally used for treating pulmonary tuberculosis, malaria, warts, lung cancer and bacillary dysentery for a long time in China. However, E. helioscopia seeds are often discarded and its medicinal value is often ignored, resulting in a waste of resources.

METHOD

In this work, widely targeted metabolomics based on UPLC-ESI-QTRAP-MS/MS methods and metware database (MWDB) were firstly used to identify the chemical compositions of EHS. Besides, network pharmacology, molecular docking and molecular dynamics simulation were performed for elucidating the potential compounds and targets of E. helioscopia seeds for the treatment of pulmonary fibrosis via common database (like TCMSP, Genecards, DAVID, STRING) and common software (like Sybyl, Cytoscape, Pymol and Schrödinger).

RESULT

The results of widely targeted metabolomics showed 231 compounds including 12 categories were identified. The highest content compositions are lipids (33.89%) followed by amino acids and derivatives (21.78%), nucleotides and derivatives (15.73%), as well as the content of functional ingredients like phenolic acids (7.33%), alkaloids (7.03%) and flavonoids (4.51%) are relatively high. Besides, the results of network pharmacology and molecular docking showed that EHS presented anti-pulmonary fibrosis medicinal value through multi-ingredients, multi-targets and multi-pathways approach. Key ingredients including 9-Hydroxy-12-oxo-15(Z)-octadecenoic acid, Nordihydrocapsiate, 1-O-Salicyl-d-glucose, 9-(Arabinosyl)hypoxanthine, Xanthosine and Galangin-7-O-glucoside. Key targets including SRC, HSP90AA1, AKT1, EGFR, JUN, EP300 and VEGFA, and key signaling pathways mainly related to AGE-RAGE, EGFR tyrosine kinase inhibitor resistance, VEGF and HIF-1 signaling pathway. Molecular dynamics simulation showed that HSP90AA1 and 9-Hydroxy-12-oxo-15(Z)-octadecenoic complex (with the highest docking score) have a stable combination effect.

CONCLUSION

In conclusion, this study revealed the chemical compositions of EHS and its anti-pulmonary fibrosis medicinal effect for the first time, it will provide scientific insight for the development of EHS as medicinal resource.

Potential of resveratrol in the treatment of interstitial lung disease

Interstitial lung disease (ILD) is a heterogeneous group of diseases characterized by lung injury caused by lung fibroblast proliferation, interstitial inflammation, and fibrosis. Different cell signal transduction pathways are activated in response to various proinflammatory or fibrotic cytokines, such as IL-6, and these cytokines are increased in different ILDs. The overexpressed cytokines and growth factors in ILD can activate TGF-β/Smad2/3/4, NF-κB, and JAK/STAT signal transduction pathways, promote the activation of immune cells, increase the release of pro-inflammatory and pro-fibrotic factors, differentiate fibroblasts into myofibroblasts, and promote the occurrence and development of ILD. This finding suggests the importance of signal transduction pathways in patients with ILD. Recent evidence suggests that resveratrol (RSV) attenuates excessive inflammation and pulmonary fibrosis by inhibiting the TGF-β/Smad2/3/4, NF-κB, and JAK/STAT signal transduction pathways and overactivation of immune cells. In this review, advances in lung protection and the underlying mechanisms of RSV are summarized, and the potential efficacy of RSV as a promising treatment option for ILD is highlighted.

Metformin attenuates fibroblast activation during pulmonary fibrosis by targeting S100A4 via AMPK-STAT3 axis

Fibroblasts activation is a crucial process for development of fibrosis during idiopathic pulmonary fibrosis pathogenesis, and transforming growth factor (TGF)-β1 plays a key regulatory role in fibroblast activation. It has been reported that metformin (MET) alleviated bleomycin (BLM)-induced pulmonary fibrosis (PF) by regulating TGF-β1-induced fibroblasts activation, but the underlying mechanisms still deserve further investigations. In this study, MET blocked α-smooth muscle actin (α-SMA) accumulation in vivo accompanied with S100A4 expression and STAT3 phosphorylation inhibition, resulting in attenuating the progression of lung fibrosis after BLM administration. We determined that S100A4 plays critical roles in fibroblasts activation in vitro, evidenced by siRNA knockdown of S100A4 expression downregulated TGF-β1 induced α-SMA production in Human fetal lung fibroblast (HFL1) cells. Importantly, we found for the first time that the expression of S100A4 in fibroblasts was regulated by STAT3. Stattic, an effective small molecule inhibitor of STAT3 phosphorylation, reduced S100A4 level in TGF-β1- treated HFL1 cells accompanied with less α-SMA production. We further found that MET, which inhibits STAT3 phosphorylation by AMPK activation, also inhibits fibroblasts activation by targeting S100A4 in vitro. Together all these results, we conclude that S100A4 contributes to TGF-β1- induced pro-fibrogenic function in fibroblasts activation, and MET was able to protect against TGF-β1-induced fibroblasts activation and BLM-induced PF by down-regulating S100A4 expression through AMPK-STAT3 axis. These results provide a useful clue for a clinical strategy to prevent PF.

Wilms Tumor 1-Driven Fibroblast Activation and Subpleural Thickening in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease that is often fatal due to the formation of irreversible scar tissue in the distal areas of the lung. Although the pathological and radiological features of IPF lungs are well defined, the lack of insight into the fibrogenic role of fibroblasts that accumulate in distinct anatomical regions of the lungs is a critical knowledge gap. Fibrotic lesions have been shown to originate in the subpleural areas and extend into the lung parenchyma through processes of dysregulated fibroproliferation, migration, fibroblast-to-myofibroblast transformation, and extracellular matrix production. Identifying the molecular targets underlying subpleural thickening at the early and late stages of fibrosis could facilitate the development of new therapies to attenuate fibroblast activation and improve the survival of patients with IPF. Here, we discuss the key cellular and molecular events that contribute to (myo)fibroblast activation and subpleural thickening in IPF. In particular, we highlight the transcriptional programs involved in mesothelial to mesenchymal transformation and fibroblast dysfunction that can be targeted to alter the course of the progressive expansion of fibrotic lesions in the distal areas of IPF lungs.

Cellular and Molecular Mechanisms in Idiopathic Pulmonary Fibrosis

The respiratory system is a well-organized multicellular organ, and disruption of cellular homeostasis or abnormal tissue repair caused by genetic deficiency and exposure to risk factors lead to life-threatening pulmonary disease including idiopathic pulmonary fibrosis (IPF). Although there is no clear etiology as the name reflected, its pathological progress is closely related to uncoordinated cellular and molecular signals. Here, we review the advances in our understanding of the role of lung tissue cells in IPF pathology including epithelial cells, mesenchymal stem cells, fibroblasts, immune cells, and endothelial cells. These advances summarize the role of various cell components and signaling pathways in the pathogenesis of idiopathic pulmonary fibrosis, which is helpful to further study the pathological mechanism of the disease, provide new opportunities for disease prevention and treatment, and is expected to improve the survival rate and quality of life of patients.

Optimizing antidotal treatment with the oral HSP90 inhibitor TAS-116 against hydrochloric acid-induced pulmonary fibrosis in mice

Exposure to high concentrations of hydrochloric acid (HCl) can lead to severe acute and chronic lung injury. In the aftermath of accidental spills, victims may be treated for the acute symptoms, but the chronic injury is often overlooked. We have developed a mouse model of acute and chronic lung injury, in which the peak of acute lung injury occurs on the day 4 after HCl exposure. We have also demonstrated that HSP90 inhibitors are effective antidotes when administered starting 24 h after HCl. In this study we examined the hypothesis that the novel oral HSP90 inhibitor TAS-116 can effectively ameliorate HCl-induced lung injury even when treatment starts at the peak of the acute injury, as late as 96 h after HCl. C57BI/6J mice were intratracheally instilled with 0.1N HCl. After 24 or 96 h, TAS-116 treatment began (3.5, 7 or 14 mg/kg, 5 times per week, p. o.) for either 2,3 or 4 or weeks. TAS-116 moderated the HCl-induced alveolar inflammation, as reflected in the reduction of white blood cells and total protein content in bronchoalveolar lavage fluid (BALF), overexpression of NLRP3 inflammasome, and inhibited the activation of pro-fibrotic pathways. Furthermore, TAS-116 normalized lung mechanics and decreased the deposition of extracellular matrix proteins in the lungs of mice exposed to HCl. Delayed and shortened treatment with TAS-116, successfully blocked the adverse chronic effects associated with acute exposure to HCl.

Identification of Signal Pathways and Hub Genes of Pulmonary Arterial Hypertension by Bioinformatic Analysis

Pulmonary arterial hypertension (PAH) is a progressive and complex pulmonary vascular disease with poor prognosis. The aim of this study was to provide a new understanding of the pathogenesis of disease and potential treatment targets for patients with PAH based on multiple-microarray analysis.Two microarray datasets (GSE53408 and GSE113439) downloaded from the Gene Expression Omnibus (GEO) database were analysed. All the raw data were processed by R, and differentially expressed genes (DEGs) were screened out by the “limma” package. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed and visualized by R and Cytoscape software. Protein-protein interactions (PPI) of DEGs were analysed based on the NetworkAnalyst online tool. A total of 442 upregulated DEGs and 84 downregulated DEGs were identified. GO enrichment analysis showed that these DEGs were mainly enriched in mitotic nuclear division, organelle fission, chromosome segregation, nuclear division, and sister chromatid segregation. Significant KEGG pathway enrichment included ribosome biogenesis in eukaryotes, RNA transport, proteoglycans in cancer, dilated cardiomyopathy, rheumatoid arthritis, vascular smooth muscle contraction, focal adhesion, regulation of the actin cytoskeleton, and hypertrophic cardiomyopathy. The PPI network identified 10 hub genes including HSP90AA1, CDC5L, MDM2, LRRK2, CFTR, IQGAP1, CAND1, TOP2A, DDX21, and HIF1A. We elucidated potential biomarkers and therapeutic targets for PAH by bioinformatic analysis, which provides a theoretical basis for future study.

Eicosatetraynoic Acid and Butyrate Regulate Human Intestinal Organoid Mitochondrial and Extracellular Matrix Pathways Implicated in Crohn's Disease Strictures

BACKGROUND

Perturbagen analysis of Crohn's disease (CD) ileal gene expression data identified small molecules including eicosatetraynoic acid (ETYA), which may exert an antifibrotic effect. We developed a patient-specific human intestinal organoid (HIO) model system to test small molecule regulation of mitochondrial and wound-healing functions implicated in stricturing behavior.

METHODS

HIOs were made from CD induced pluripotent stem cells with and without a loss-of-function haplotype in the DUOX2 gene implicated in ileal homeostasis and characterized under basal conditions and following exposure to butyrate and ETYA using RNA sequencing, flow cytometry, and immunofluorescent and polarized light microscopy. Mitochondrial activity was measured using high-resolution respirometry and tissue stiffness using atomic force microscopy.

RESULTS

HIOs expressed core mitochondrial and extracellular matrix (ECM) genes and enriched biologic functions implicated in CD ileal strictures; ECM gene expression was suppressed by both butyrate and ETYA, with butyrate also suppressing genes regulating epithelial proliferation. Consistent with this, butyrate, but not ETYA, exerted a profound effect on HIO epithelial mitochondrial function, reactive oxygen species production, and cellular abundance. Butyrate and ETYA suppressed HIO expression of alpha smooth muscle actin expressed by myofibroblasts, type I collagen, and collagen protein abundance. HIOs exhibited tissue stiffness comparable to normal human ileum; this was reduced by chronic ETYA exposure in HIOs carrying the DUOX2 loss-of-function haplotype.

CONCLUSIONS

ETYA regulates ECM genes implicated in strictures and suppresses collagen content and tissue stiffness in an HIO model. HIOs provide a platform to test personalized therapeutics, including small molecules prioritized by perturbagen analysis.

Proteomics-based investigation of cerebrovascular molecular mechanisms in cerebral amyloid angiopathy by the FFPE-LMD-PCT-SWATH method

Background

Cerebral amyloid angiopathy (CAA) occurs in 80% of patients with Alzheimer’s disease (AD) and is mainly caused by the abnormal deposition of Aβ in the walls of cerebral blood vessels. Cerebrovascular molecular mechanisms in CAA were investigated by using comprehensive and accurate quantitative proteomics.

Methods

Concerning the molecular mechanisms specific to CAA, formalin-fixed paraffin-embedded (FFPE) sections were prepared from patients having AD neuropathologic change (ADNC) with severe cortical Aβ vascular deposition (ADNC +/CAA +), and from patients having ADNC without vascular deposition of Aβ (ADNC +/CAA −; so called, AD). Cerebral cortical vessels were isolated from FFPE sections using laser microdissection (LMD), processed by pressure cycling technology (PCT), and applied to SWATH (sequential window acquisition of all theoretical fragment ion spectra) proteomics.

Results

The protein expression levels of 17 proteins in ADNC +/CAA +/H donors (ADNC +/CAA + donors with highly abundant Aβ in capillaries) were significantly different from those in ADNC +/CAA − and ADNC −/CAA − donors. Furthermore, we identified 56 proteins showing more than a 1.5-fold difference in average expression levels between ADNC +/CAA + and ADNC −/CAA − donors, and were significantly correlated with the levels of Aβ or Collagen alpha-2(VI) chain (COL6A2) (CAA markers) in 11 donors (6 ADNC +/CAA + and 5 ADNC −/CAA −). Over 70% of the 56 proteins showed ADNC +/CAA + specific changes in protein expression. The comparative analysis with brain parenchyma showed that more than 90% of the 56 proteins were vascular-specific pathological changes. A literature-based pathway analysis showed that 42 proteins are associated with fibrosis, oxidative stress and apoptosis. This included the increased expression of Heat shock protein HSP 90-alpha, CD44 antigen and Carbonic anhydrase 1 which are inhibited by potential drugs against CAA.

Conclusions

The combination of LMD-based isolation of vessels from FFPE sections, PCT-assisted sample processing and SWATH analysis (FFPE-LMD-PCT-SWATH method) revealed for the first time the changes in the expression of many proteins that are involved in fibrosis, ROS production and cell death in ADNC +/CAA +  (CAA patients) vessels. The findings reported herein would be useful for developing a better understanding of the pathology of CAA and for promoting the discovery and development of drugs and biomarkers for CAA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12987-022-00351-x.

Profibrotic Role of Inducible Heat Shock Protein 90α Isoform in Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune disease that affects skin and multiple internal organs. TGF-β, a central trigger of cutaneous fibrosis, activates fibroblasts with the involvement of the stress-inducible chaperone heat shock protein 90 isoform α (Hsp90α). Available evidence supports overexpression and secretion of Hsp90α as a feature in profibrotic pathological conditions. The aim of this work is to investigate the expression and function of Hsp90α in experimental models of skin fibrosis such as human fibroblasts, C57BL/6 mice, and in human SSc. For this purpose, we generated a new experimental model based on doxorubicin administration with improved characteristics with respect to the bleomycin model. We visualized disease progression in vivo by fluorescence imaging. In this work, we obtained Hsp90α mRNA overexpression in human skin fibroblasts, in bleomycin- and doxorubicin-induced mouse fibrotic skin, and in lungs of bleomycin- and doxorubicin-treated mice. Hsp90α-deficient mice showed significantly decreased skin thickness compared with wild-type mice in both animal models. In SSc patients, serum Hsp90α levels were increased in patients with lung involvement and in patients with the diffuse form of SSc (dSSc) compared with patients with the limited form of SSc. The serum Hsp90α levels of patients dSSc were correlated with the Rodnan score and the forced vital capacity variable. These results provide new supportive evidence of the contribution of the Hsp90α isoform in the development of skin fibrosis. In SSc, these results indicated that higher serum levels were associated with dSSc and lung fibrosis.

Modeling Kaempferol as a Potential Pharmacological Agent for COVID-19/PF Co-Occurrence Based on Bioinformatics and System Pharmacological Tools

Objective: People suffering from coronavirus disease 2019 (COVID-19) are prone to develop pulmonary fibrosis (PF), but there is currently no definitive treatment for COVID-19/PF co-occurrence. Kaempferol with promising antiviral and anti-fibrotic effects is expected to become a potential treatment for COVID-19 and PF comorbidities. Therefore, this study explored the targets and molecular mechanisms of kaempferol against COVID-19/PF co-occurrence by bioinformatics and network pharmacology.

Methods: Various open-source databases and Venn Diagram tool were applied to confirm the targets of kaempferol against COVID-19/PF co-occurrence. Protein-protein interaction (PPI), MCODE, key transcription factors, tissue-specific enrichment, molecular docking, Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used to clarify the influential molecular mechanisms of kaempferol against COVID-19 and PF comorbidities.

Results: 290 targets and 203 transcription factors of kaempferol against COVID-19/PF co-occurrence were captured. Epidermal growth factor receptor (EGFR), proto-oncogene tyrosine-protein kinase SRC (SRC), mitogen-activated protein kinase 3 (MAPK3), mitogen-activated protein kinase 1 (MAPK1), mitogen-activated protein kinase 8 (MAPK8), RAC-alpha serine/threonine-protein kinase (AKT1), transcription factor p65 (RELA) and phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha isoform (PIK3CA) were identified as the most critical targets, and kaempferol showed effective binding activities with the above critical eight targets. Further, anti-COVID-19/PF co-occurrence effects of kaempferol were associated with the regulation of inflammation, oxidative stress, immunity, virus infection, cell growth process and metabolism. EGFR, interleukin 17 (IL-17), tumor necrosis factor (TNF), hypoxia inducible factor 1 (HIF-1), phosphoinositide 3-kinase/AKT serine/threonine kinase (PI3K/AKT) and Toll-like receptor signaling pathways were identified as the key anti-COVID-19/PF co-occurrence pathways.

Conclusion: Kaempferol is a candidate treatment for COVID-19/PF co-occurrence. The underlying mechanisms may be related to the regulation of critical targets (EGFR, SRC, MAPK3, MAPK1, MAPK8, AKT1, RELA, PIK3CA and so on) and EGFR, IL-17, TNF, HIF-1, PI3K/AKT and Toll-like receptor signaling pathways. This study contributes to guiding development of new drugs for COVID-19 and PF comorbidities.

Heat shock proteins in pulmonary fibrosis: pawns of cell homeostasis

Idiopathic lung fibrosis (IPF) is a fatal disease that primarily affects the elderly. Up to date, the specific pathophysiology of IPF remains unknown. However, it is theorized to be caused by chronic repetitive injuries to the alveolar epithelium, eventually exhausting the stem cell capacity and activating pathological pathways. Heat shock proteins (HSPs), a category of stress response proteins, are also suggested to contribute to IPF pathophysiology. Furthermore, HSPs are key components in the regulation of cell homeostasis and act as chaperones for a multitude of new proteins. This review thoroughly evaluates the roles that specific HSPs, HSP90, HSP70, and HSP47, have in the fibrotic process. A close look into the roles of these HSPs in IPF pathophysiology will give valuable insight into the future of IPF treatment and prevention.

The Heat Shock Protein 90 Inhibitor, AT13387, Protects the Alveolo-Capillary Barrier and Prevents HCl-Induced Chronic Lung Injury and Pulmonary Fibrosis

Hydrochloric acid (HCl) exposure causes asthma-like conditions, reactive airways dysfunction syndrome, and pulmonary fibrosis. Heat Shock Protein 90 (HSP90) is a molecular chaperone that regulates multiple cellular processes. HSP90 inhibitors are undergoing clinical trials for cancer and are also being studied in various pre-clinical settings for their anti-inflammatory and anti-fibrotic effects. Here we investigated the ability of the heat shock protein 90 (HSP90) inhibitor AT13387 to prevent chronic lung injury induced by exposure to HCl in vivo and its protective role in the endothelial barrier in vitro. We instilled C57Bl/6J mice with 0.1N HCl (2 µL/g body weight, intratracheally) and after 24 h began treatment with vehicle or AT13387 (10 or 15 mg/kg, SC), administered 3×/week; we analyzed histological, functional, and molecular markers 30 days after HCl. In addition, we monitored transendothelial electrical resistance (TER) and protein expression in a monolayer of human lung microvascular endothelial cells (HLMVEC) exposed to HCl (0.02 N) and treated with vehicle or AT13387 (2 µM). HCl provoked persistent alveolar inflammation; activation of profibrotic pathways (MAPK/ERK, HSP90); increased deposition of collagen, fibronectin and elastin; histological evidence of fibrosis; and a decline in lung function reflected in a downward shift in pressure-volume curves, increased respiratory system resistance (Rrs), elastance (Ers), tissue damping (G), and hyperresponsiveness to methacholine. Treatment with 15 mg/kg AT13387reduced alveolar inflammation, fibrosis, and NLRP3 staining; blocked activation of ERK and HSP90; and attenuated the deposition of collagen and the development of chronic lung injury and airway hyperreactivity. In vitro, AT13387 prevented HCl-induced loss of barrier function and AKT, ERK, and ROCK1 activation, and restored HSP70 and cofilin expression. The HSP90 inhibitor, AT13387, represents a promising drug candidate for chronic lung injury that can be administered subcutaneously in the field, and at low, non-toxic doses.

Hsp90 in Human Diseases: Molecular Mechanisms to Therapeutic Approaches

The maturation of hemeprotein dictates that they incorporate heme and become active, but knowledge of this essential cellular process remains incomplete. Studies on chaperon Hsp90 has revealed that it drives functional heme maturation of inducible nitric oxide synthase (iNOS), soluble guanylate cyclase (sGC) hemoglobin (Hb) and myoglobin (Mb) along with other proteins including GAPDH, while globin heme maturations also need an active sGC. In all these cases, Hsp90 interacts with the heme-free or apo-protein and then drives the heme maturation by an ATP dependent process before dissociating from the heme-replete proteins, suggesting that it is a key player in such heme-insertion processes. As the studies on globin maturation also need an active sGC, it connects the globin maturation to the NO-sGC (Nitric oxide-sGC) signal pathway, thereby constituting a novel NO-sGC-Globin axis. Since many aggressive cancer cells make Hbβ/Mb to survive, the dependence of the globin maturation of cancer cells places the NO-sGC signal pathway in a new light for therapeutic intervention. Given the ATPase function of Hsp90 in heme-maturation of client hemeproteins, Hsp90 inhibitors often cause serious side effects and this can encourage the alternate use of sGC activators/stimulators in combination with specific Hsp90 inhibitors for better therapeutic intervention.

Extravesicular TIMP-1 is a non-invasive independent prognostic marker and potential therapeutic target in colorectal liver metastases

Molecular reprogramming of stromal microarchitecture by tumour-derived extracellular vesicles (EVs) is proposed to favour pre-metastatic niche formation. We elucidated the role of extravesicular tissue inhibitor of matrix metalloproteinase-1 (TIMP1^EV) in pro-invasive extracellular matrix (ECM) remodelling of the liver microenvironment to aid tumour progression in colorectal cancer (CRC). Immunohistochemistry analysis revealed a high expression of stromal TIMP1 in the invasion front that was associated with poor progression-free survival in patients with colorectal liver metastases. Molecular analysis identified TIMP1^EV enrichment in CRC-EVs as a major factor in the induction of TIMP1 upregulation in recipient fibroblasts. Mechanistically, we proved that EV-mediated TIMP1 upregulation in recipient fibroblasts induced ECM remodelling. This effect was recapitulated by human serum-derived EVs providing strong evidence that CRC release active EVs into the blood circulation of patients for the horizontal transfer of malignant traits to recipient cells. Moreover, EV-associated TIMP1 binds to HSP90AA, a heat-shock protein, and the inhibition of HSP90AA on human-derived serum EVs attenuates TIMP1^EV-mediated ECM remodelling, rendering EV-associated TIMP1 a potential therapeutic target. Eventually, in accordance with REMARK guidelines, we demonstrated in three independent cohorts that EV-bound TIMP1 is a robust circulating biomarker for a non-invasive, preoperative risk stratification in patients with colorectal liver metastases.

Hsp90 Levels in Idiopathic Inflammatory Myopathies and Their Association With Muscle Involvement and Disease Activity: A Cross-Sectional and Longitudinal Study

Background

Heat shock proteins (Hsp) are chaperones playing essential roles in skeletal muscle physiology, adaptation to exercise or stress, and activation of inflammatory cells. We aimed to assess Hsp90 in patients with idiopathic inflammatory myopathies (IIM) and its association with IIM-related features.

Methods

Hsp90 plasma levels were analyzed in a cross-sectional cohort (277 IIM patients and 157 healthy controls [HC]) and two longitudinal cohorts to assess the effect of standard-of-care pharmacotherapy (n=39 in early disease and n=23 in established disease). Hsp90 and selected cytokines/chemokines were measured by commercially available ELISA and human Cytokine 27-plex Assay.

Results

Hsp90 plasma levels were increased in IIM patients compared to HC (median [IQR]: 20.2 [14.3–40.1] vs 9.8 [7.5–13.8] ng/mL, p<0.0001). Elevated Hsp90 was found in IIM patients with pulmonary, cardiac, esophageal, and skeletal muscle involvement, with higher disease activity or damage, and with elevated muscle enzymes and crucial cytokines/chemokines involved in the pathogenesis of myositis (p<0.05 for all). Plasma Hsp90 decreased upon pharmacological treatment in both patients with early and established disease. Notably, Hsp90 plasma levels were slightly superior to traditional biomarkers, such as C-reactive protein and creatine kinase, in differentiating IIM from HC, and IIM patients with cardiac involvement and interstitial lung disease from those without these manifestations.

Conclusions

Hsp90 is increased systemically in patients with IIM. Plasma Hsp90 could become an attractive soluble biomarker of disease activity and damage and a potential predictor of treatment response in IIM.

HSP90 as a regulator of extracellular matrix dynamics

The extracellular matrix (ECM) is a dynamic and organised extracellular network assembled from proteins and carbohydrates exported from the cell. The ECM is critical for multicellular life, providing spatial and temporal cellular cues to maintain tissue homeostasis. Consequently, ECM production must be carefully balanced with turnover to ensure homeostasis; ECM dysfunction culminates in disease. Hsp90 is a molecular chaperone central to protein homeostasis, including in the ECM. Intracellular and extracellular Hsp90 isoforms collaborate to regulate the levels and status of proteins in the ECM via multiple mechanisms. In so doing, Hsp90 regulates ECM dynamics, and changes in Hsp90 levels or activity support the development of ECM-related diseases, like cancer and fibrosis. Consequently, Hsp90 levels may have prognostic value, while inhibition of Hsp90 may have therapeutic potential in conditions characterised by ECM dysfunction.

Single-Cell RNA Sequencing Reveals Multiple Pathways and the Tumor Microenvironment Could Lead to Chemotherapy Resistance in Cervical Cancer

Background

Cervical cancer is one of the most common gynecological cancers worldwide. The tumor microenvironment significantly influences the therapeutic response and clinical outcome. However, the complex tumor microenvironment of cervical cancer and the molecular mechanisms underlying chemotherapy resistance are not well studied. This study aimed to comprehensively analyze cells from pretreated and chemoresistant cervical cancer tissues to generate a molecular census of cell populations.

Methods

Biopsy tissues collected from patients with cervical squamous cell carcinoma, cervical adenocarcinoma, and chronic cervicitis were subjected to single-cell RNA sequencing using the 10× Genomics platform. Unsupervised clustering analysis of cells was performed to identify the main cell types, and important cell clusters were reclustered into subpopulations. Gene expression profiles and functional enrichment analysis were used to explore gene expression and functional differences between cell subpopulations in cervicitis and cervical cancer samples and between chemoresistant and chemosensitive samples.

Results

A total of 24,371 cells were clustered into nine separate cell types, including immune and non-immune cells. Differentially expressed genes between chemoresistant and chemosensitive patients enriched in the phosphoinositide 3-kinase (PI3K)/AKT pathway were involved in tumor development, progression, and apoptosis, which might lead to chemotherapy resistance.

Conclusions

Our study provides a comprehensive overview of the cancer microenvironment landscape and characterizes its gene expression and functional difference in chemotherapy resistance. Consequently, our study deepens the insights into cervical cancer biology through the identification of gene markers for diagnosis, prognosis, and therapy.

Dysregulated overexpression of Sox9 induces fibroblast activation in pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a fatal fibrotic lung disease associated with unremitting fibroblast activation including fibroblast-to-myofibroblast transformation (FMT), migration, resistance to apoptotic clearance, and excessive deposition of extracellular matrix (ECM) proteins in the distal lung parenchyma. Aberrant activation of lung-developmental pathways is associated with severe fibrotic lung disease; however, the mechanisms through which these pathways activate fibroblasts in IPF remain unclear. Sry-box transcription factor 9 (Sox9) is a member of the high-mobility group box family of DNA-binding transcription factors that are selectively expressed by epithelial cell progenitors to modulate branching morphogenesis during lung development. We demonstrate that Sox9 is upregulated via MAPK/PI3K-dependent signaling and by the transcription factor Wilms' tumor 1 in distal lung-resident fibroblasts in IPF. Mechanistically, using fibroblast activation assays, we demonstrate that Sox9 functions as a positive regulator of FMT, migration, survival, and ECM production. Importantly, our in vivo studies demonstrate that fibroblast-specific deletion of Sox9 is sufficient to attenuate collagen deposition and improve lung function during TGF-α-induced pulmonary fibrosis. Using a mouse model of bleomycin-induced pulmonary fibrosis, we show that myofibroblast-specific Sox9 overexpression augments fibroblast activation and pulmonary fibrosis. Thus, Sox9 functions as a profibrotic transcription factor in activating fibroblasts, illustrating the potential utility of targeting Sox9 in IPF treatment.

Atractylodin Suppresses TGF-β-Mediated Epithelial-Mesenchymal Transition in Alveolar Epithelial Cells and Attenuates Bleomycin-Induced Pulmonary Fibrosis in Mice

Idiopathic pulmonary fibrosis (IPF) is characterized by fibrotic change in alveolar epithelial cells and leads to the irreversible deterioration of pulmonary function. Transforming growth factor-beta 1 (TGF-β1)-induced epithelial-mesenchymal transition (EMT) in type 2 lung epithelial cells contributes to excessive collagen deposition and plays an important role in IPF. Atractylodin (ATL) is a kind of herbal medicine that has been proven to protect intestinal inflammation and attenuate acute lung injury. Our study aimed to determine whether EMT played a crucial role in the pathogenesis of pulmonary fibrosis and whether EMT can be utilized as a therapeutic target by ATL treatment to mitigate IPF. To address this topic, we took two steps to investigate: 1. Utilization of anin vitro EMT model by treating alveolar epithelial cells (A549 cells) with TGF-β1 followed by ATL treatment for elucidating the underlying pathways, including Smad2/3 hyperphosphorylation, mitogen-activated protein kinase (MAPK) pathway overexpression, Snail and Slug upregulation, and loss of E-cadherin. Utilization of an in vivo lung injury model by treating bleomycin on mice followed by ATL treatment to demonstrate the therapeutic effectiveness, such as, less collagen deposition and lower E-cadherin expression. In conclusion, ATL attenuates TGF-β1-induced EMT in A549 cells and bleomycin-induced pulmonary fibrosis in mice.

Extracellular Heat Shock Proteins as Therapeutic Targets and Biomarkers in Fibrosing Interstitial Lung Diseases

Interstitial lung diseases (ILDs) include a large number of diseases and causes with variable outcomes often associated with progressive fibrosis. Although each of the individual fibrosing ILDs are rare, collectively, they affect a considerable number of patients, representing a significant burden of disease. Idiopathic pulmonary fibrosis (IPF) is the typical chronic fibrosing ILD associated with progressive decline in lung. Other fibrosing ILDs are often associated with connective tissues diseases, including rheumatoid arthritis-ILD (RA-ILD) and systemic sclerosis-associated ILD (SSc-ILD), or environmental/drug exposure. Given the vast number of progressive fibrosing ILDs and the disparities in clinical patterns and disease features, the course of these diseases is heterogeneous and cannot accurately be predicted for an individual patient. As a consequence, the discovery of novel biomarkers for these types of diseases is a major clinical challenge. Heat shock proteins (HSPs) are molecular chaperons that have been extensively described to be involved in fibrogenesis. Their extracellular forms (eHSPs) have been recently and successfully used as therapeutic targets or circulating biomarkers in cancer. The current review will describe the role of eHSPs in fibrosing ILDs, highlighting the importance of these particular stress proteins to develop new therapeutic strategies and discover potential biomarkers in these diseases.