Background: Idiopathic pulmonary fibrosis (IPF) is an age-related disease with no cure. Mesenchymal stem cell (MSC)-based therapy has emerged as a novel strategy for IPF treatment. Nevertheless, MSCs derived from patients with IPF (IPF-MSCs) become senescent, thereby reducing their beneficial effects in IPF. MicroRNAs (miRNAs) mediate the senescence of MSCs, but the underlying mechanisms are not fully understood. We investigated the mechanisms by which miR-199a-5p regulates IPF-MSC senescence and whether its inhibition could rejuvenate IPF-MSCs and enhance their therapeutic efficacy. Methods: Control-MSCs and IPF-MSCs were isolated from the adipose tissue of age-matched healthy and IPF donors, respectively. Cell senescence was examined by senescence-associated β-galactosidase (SA-β-gal) staining. The level of miR-199a-5p was measured by RT-PCR. Autophagy was determined using a transmission electron microscope (TEM). The therapeutic efficacy of anti-miR-199a-5p-IPF-MSCs was assessed using a mouse model of bleomycin-induced lung fibrosis. Results: Despite similar surface makers, IPF-MSCs exhibited increased cellular senescence and decreased proliferative capacity compared with control-MSCs. The expression of miR-199a-5p was significantly enhanced in the serum of IPF patients and IPF-MSCs compared with that of healthy donors and control-MSCs. The upregulation of miR-199a-5p induced senescence of control-MSCs, whereas the downregulation rescued IPF-MSC senescence. Mechanistically, miR-155-5p suppressed autophagy of MSCs via the AMPK signaling pathway by downregulating the expression of Sirtuin 1(Sirt1), resulting in cellular senescence. Accordingly, miR-155-5p inhibition promoted autophagy and ameliorated IPF-MSC senescence by activating the Sirt1/AMPK signaling pathway. Compared with IPF-MSCs, the transplantation of anti-miR-199a-5p-IPF-MSCs increased the ability to prevent progression of pulmonary fibrosis in bleomycin-treated mice. Conclusions: Our study shows that miR-199a-5p regulates MSC senescence in patients with IPF by regulating the Sirt1/AMPK signaling pathway and miR-199a-5p is a novel target to rejuvenate IPF-MSCs and enhance their beneficial effects.

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease of unknown etiology. Immune disorders play an important role in IPF pathogenesis. Here, we show that Th9 cells differentiate and activate in the lung tissue of patients with IPF and bleomycin (BLM)-induced lung fibrosis mice. Moreover, we found that Th9 cells promote pulmonary fibrosis in two ways. On the one hand, Th9 cells promote fibroblast differentiation, activation, and collagen secretion by secreting IL-9. On the other hand, they promote differentiation of Th0 cells into Th2 cells by secreting IL-4. Th9 cells and Th2 cells can promote each other, accelerating the Th1/Th2 imbalance and eventually forming a positive feedback of pulmonary fibrosis. In addition, we found that neutralizing IL-9 in both preventive and therapeutic settings ameliorates bleomycin-induced pulmonary fibrosis. Furthermore, we identified several critical signaling pathways involved in the effect of neutralizing IL-9 on pulmonary fibrosis by proteomics study. From an immunological perspective, we elucidated the novel role and underlying mechanism of Th9 cells in pulmonary fibrosis. Our study suggested that Th9-based immunotherapy may be employed as a treatment strategy for IPF.

Background and objective: Idiopathic pulmonary fibrosis (IPF) is an aggressive fibrotic pulmonary disease with spatially and temporally heterogeneous alveolar lesions. There are no early diagnostic biomarkers, limiting our understanding of IPF pathogenesis.Methods: Lung tissue from surgical lung biopsy of patients with early-stage IPF (n = 7), transplant-stage IPF (n = 2), and healthy controls (n = 6) were subjected to mRNA sequencing and verified by real-time quantitative PCR (RT-qPCR), immunohistochemistry, Western blot, and single-cell RNA sequencing (scRNA-Seq).Results: Three hundred eighty differentially expressed transcripts (DETs) were identified in IPF that were principally involved in extracellular matrix (ECM) remodeling, lipid metabolism, and immune effect. Of these DETs, 21 (DMD, MMP7, POSTN, ECM2, MMP13, FASN, FADS1, SDR16C5, ACAT2, ACSL1, CYP1A1, UGT1A6, CXCL13, CXCL5, CXCL14, IL5RA, TNFRSF19, CSF3R, S100A9, S100A8, and S100A12) were selected and verified by RT-qPCR. Differences in DMD, FASN, and MMP7 were also confirmed at a protein level. Analysis of scRNA-Seq was used to trace their cellular origin to determine which lung cells regulated them. The principal cell sources of DMD were ciliated cells, alveolar type I/II epithelial cells (AT cells), club cells, and alveolar macrophages (AMs); MMP7 derives from AT cells, club cells, and AMs, while FASN originates from AT cells, ciliated cells, and AMs.Conclusion: Our data revealed a comprehensive transcriptional mRNA profile of IPF and demonstrated that ECM remodeling, lipid metabolism, and immune effect were collaboratively involved in the early development of IPF.

Background: Reported data on the disease spectrum of interstitial lung diseases (ILDs) of China are sparse and varied. We aimed to investigate the spectrum of ILDs and the distribution of diagnostic methods under a uniform diagnosis. Methods: This retrospective study enrolled ILDs cases from Guangzhou Institute of Respiratory Health (GIRH). All cases were classified into specific subgroups of ILDs according to updated guidelines. Results: A total of 1,945 subjects were enrolled from January 2012 to December 2017. The mean age was 57.9 years, and 1,080 (55.5%) patients were male. The most common subtype of ILDs was idiopathic pulmonary fibrosis (IPF, 20.3%), followed by interstitial pneumonia with autoimmune features (IPAF, 17.9%), connective tissue disease associated ILD (CTD-ILD, 18.3%) and unclassifiable idiopathic interstitial pneumonia (UIIP, 14.7%). A total of 818 (42.1%) patients underwent lung biopsy in order to obtain a histological diagnose. TBLB was performed in 565 (29.0%) patients, eleven of whom underwent SLB because TBLB failed to obtain lung samples. SLB was performed in 213 (11.0%) patients and TBCB was performed in 51 (2.6%) patients. Among them, histological results were considered clinically helpful in 722 (88.3%) cases, and provided definitive histopathological diagnoses in 368 cases. Surgical lung biopsy (SLB) was performed in 213 (10.9%) subjects, while 115 (54.0%) cases were performed among the idiopathic interstitial pneumonia (IIP). Among SLB cases in IIP, the highest rate of SLB was desquamative interstitial pneumonia/respiratory bronchiolitis-interstitial lung disease (DIP/RB-ILD, 10/10), lymphoid interstitial pneumonia (LIP, 9/9), followed by cryptogenic organizing (COP, 18/26), nonspecific interstitial pneumonia (NSIP, 22/53), IPF (43/395), UIIP (13/285). Conclusions: IPF was the most common ILDs in our ILD center, followed by IPAF, CTD-ILD and UIIP. Histological information may help to establish diagnostic algorithm in ILD.

The application of transbronchial lung cryobiopsy (TBLC) and uniportal and tubeless video-assisted thoracic surgery (UT-VATS) in the multidisciplinary diagnosis of interstitial lung disease (ILD) has not been demonstrated in real-world clinical practice. This prospective study included 137 patients with no definitive diagnosis who were the subject of two multidisciplinary discussion (MDD) sessions. As indicated in the first MDD, 67 patients underwent UT-VATS and 70 underwent TBLC. The specificity of biopsy information and its contribution to final MDD diagnosis were evaluated in the second MDD. The post-operative complications and hospitalization costs associated with the two biopsy methods were compared. UT-VATS was favored for patients initially diagnosed with idiopathic pulmonary fibrosis (IPF), bronchiolitis-associated interstitial lung disease (RB-ILD)/desquamative interstitial pneumonia (DIP) and undefined idiopathic interstitial pneumonia (UIIP), while TBLC was preferred for pulmonary lymphangioleiomyomatosis (PLAM) and pulmonary alveolar proteinosis (PAP). The spirometry parameters were better in patients who underwent UT-VATS than those who underwent TBLC. UT-VATS provided more specific pathological results than TBLC (85.7 vs 73.7%, p = 0.06). In patients initially diagnosed with UIIP, pathological information from UT-VATS was more clinically useful than that obtained from TBLC, although both tests contributed similarly to cases initially diagnosed as interstitial pneumonia with auto-immune features (IPAF)/connective tissue disease-related ILD (CTD-ILD). The safety of UT-VATS was comparable with TBLC although TBLC was cheaper during hospitalization (US$4,855.7 vs US$3,590.9, p < 0.001). multidisciplinary discussion decisions about biopsies were driven by current knowledge of sampling and diagnosis capacity as well as potential risks of different biopsy methods. The current MDD considered UT-VATS more informative than TBLC in cases initially diagnosed as UIIP although they were equally valuable in patients initially diagnosed with IPAF/CTD-ILD.

Recently, fibroblast activation protein (FAP), an overexpressed transmembrane protein of activated fibroblast in pulmonary fibrosis, has been considered as the new target for diagnosing and treating pulmonary fibrosis. In this work, mesoporous polydopamine (MPDA), which is facile prepared and easily modified, is developed as a carrier to load antifibrosis drug pirfenidone (PFD) and linking FAP inhibitor (FAPI) to realize lesion-targeted drug delivery for pulmonary fibrosis therapy. We have found that PFD@MPDA-FAPI is well biocompatible and with good properties of antifibrosis, when ICG labels MPDA-FAPI, the accumulation of the nanodrug at the fibrosis lung in vivo can be observed by NIR imaging, and the antifibrosis properties of PFD@MPDA-FAPI in vivo were also better than those of pure PFD and PFD@MPDA; therefore, the easily produced and biocompatible nanodrug PFD@MPDA-FAPI developed in this study is promising for further clinical translations in pulmonary fibrosis antifibrosis therapy.