Mouse Model Of Idiopathic Pulmonary Fibrosis Research Articles

Comparison of The Novel K Ca 3.1 Inhibitor SAN903 with Nintedanib and Pirfenidone In A Model of Idiopathic Pulmonary Fibrosis

Hypothesis Idiopathic pulmonary fibrosis (IPF) is a chronic and debilitating disease characterized by progressive lung fibrosis and declined function. IPF is a fatal condition with an expected survival time of 3-4 years, despite two medicines, nintedanib and pirfenidone, having been registered by the FDA/EMA. There is a clear need for more effective treatment options. KCa3.1 is a Ca2+-activated K+- channel expressed in fibroblasts/myofibroblasts, immune cells, and many epithelia/endothelia. The KCa3.1 channel is reported to control proliferation, migration, as well as cytokine release and collagen deposition in fibrosis models and inhibition of the KCa3.1 channel is hypothesized to ameliorate this inflammatory/fibrotic cascade. This study reports the testing of a novel KCa3.1 inhibitor, SAN903, compared to nintedanib and pirfenidone in a mouse model of IPF. Method C57BL/6J mice were given a single lung instillation of bleomycin (1.5 IU/kg) or saline (sham) and followed for 21 days. Groups of 2 × 8 animals (experiment lines 1 and 2) were dosed with SAN903 (30mg/kg, bid, po), nintedanib (60mg/kg, qd, po), pirfenidone (200mg/kg, bid, po), or vehicle (bid, po). Dose selection for nintedanib and pirfenidone were taken from the literature and adjusted to approach calculated human equivalent doses. Physical examination and body weights were recorded daily. At day 22, line 1 mice were sacrificed, and the lungs prepared for histochemical evaluation (H&E and MT staining). Line 2 mice were anesthetized and bronchoalveolar lavage fluid (BALF) collected for analysis. Statistical testing consisted of one-way/repeated measures ANOVA followed by Fisher´s LSD test with significance set at alpha P<0.05. Result Increase in histopathological score, biochemical parameters and cellular infiltration indicated robust and statistically significant inflammation/fibrosis in the vehicle group (p<0.0001 vs sham). No mortalities were reported during the study. SAN903 significantly (N=16) counteracted body weight decline caused by bleomycin, whereas nintedanib showed a trend towards improved outcomes and pirfenidone significantly worsened the decline. Histology revealed significant reductions of both inflammation and fibrosis in the SAN903 treated group (P=0.03), whereas nintedanib showed a numerical effect and pirfenidone trended towards impaired outcomes. The difference in effect between SAN903 and pirfenidone on fibrosis score was statistically significant (p=0.002). Analysis of BALF showed no significant effects on total or differential cell counts by any compound, whereas nintedanib significantly reduced TGF-1β (p=0.003) and SAN903 showed trend of inhibition (p=0.15). None of the compounds significantly decreased lung hydroxyproline contents. Conclusion: SAN903 reduced lung inflammation and fibrosis in the mouse bleomycin-model of lung fibrosis. The effects of SAN903 on lung pathology seem superior to the two standard-of-care medicines for IPF.

Protective Role of the Nucleic Acid Sensor STING in Pulmonary Fibrosis.

Idiopathic pulmonary fibrosis (IPF) is the most common and severe type of interstitial lung disease for which current treatments display limited efficacy. IPF is largely driven by host-derived danger signals released upon recurrent local tissue damage. Here we explored the roles of self-DNA and stimulator of interferon genes (STING), a protein belonging to an intracellular DNA sensing pathway that leads to type I and/or type III interferon (IFN) production upon activation. Using a mouse model of IPF, we report that STING deficiency leads to exacerbated pulmonary fibrosis with increased collagen deposition in the lungs and excessive remodeling factors expression. We further show that STING-mediated protection does not rely on type I IFN signaling nor on IL-17A or TGF-β modulation but is associated with dysregulated neutrophils. Together, our data support an unprecedented immunoregulatory function of STING in lung fibrosis.

Efficacy of YAP1-gene Knockdown to Inhibit Alveolar-Epithelial-Cell Senescence and Alleviate Idiopathic Pulmonary Fibrosis (IPF).

The prevalence of idiopathic pulmonary fibrosis (IPF) increases with age and is associated with senescence of alveolar epithelial cells (AECs). AEC senescence in pulmonary cells mediates IPF. We herein aimed to determine if YAP1 gene knockdown, a member of the Hippo/YAP signal pathway, in the bleomycin (BLM)-induced mouse model of IPF, inhibits onset of senescence of AECs and alleviates IPF. Adeno-associated viruses (AAVs) expressing Yes-associated protein 1 (YAP1) short hairpin RNA (shRNA) were delivered into the lung of BLM-induced IPF mice via intratracheal injection, to knockdown the YAP1 gene in AECs. The mice were assigned to 4 groups: G1: control (normal mice); G2: IPF mice; G3: IPF + AAV/YAP1; G4: IPF + AAV/scramble. After 28 days, AECs were examined for senescence using H&E staining, Masson's trichrome Staining, senescence-associated ß-galactosidase (SA-β-gal) staining, western blotting and co-immunofluorescence staining, to determine the expression of YAP1, Smad-3 and p21, in order to determine the induction of senescence of ACEs. The severity of IPF determined by H&E staining, Masson's staining and immunofluorescence (IF) staining was positively correlated with the senescence of AECs. Down-regulation of YAP1 expression of the Hippo-signaling pathway, determined by western blotting in AECs, alleviated pulmonary fibrosis as determined by Masson's staining. Down regulation of YAP1 expression reduced the senescence of AECs as determined by ß-galactosidase (SA-β-gal) staining, which alleviated the clinical symptoms of IPF mice, as determined by body weight and lung index. Down-regulation of YAP1 expression in AECs inhibited AEC senescence which is thought to be the cause of IPF. Therefore, future studies can focus on inhibiting YAP1 to effectively treat IPF.

The heterodimer S100A8/A9 is a potent therapeutic target for idiopathic pulmonary fibrosis.

In patients with interstitial pneumonia, pulmonary fibrosis is an irreversible condition that can cause respiratory failure. Novel treatments for pulmonary fibrosis are necessary. Inflammation is thought to activate lung fibroblasts, resulting in pulmonary fibrosis. Of the known inflammatory molecules, we have focused on S100A8/A9 from the onset of inflammation to the subsequent progression of inflammation. Our findings confirmed the high expression of S100A8/A9 in specimens from patients with pulmonary fibrosis. An active role of S100A8/A9 was demonstrated not only in the proliferation of fibroblasts but also in the fibroblasts' differentiation to myofibroblasts (the active form of fibroblasts). S100A8/A9 also forced fibroblasts to upregulate the production of collagen. These effects were induced via the receptor of S100A8/A9, i.e., the receptor for advanced glycation end products (RAGE), on fibroblasts. The anti-S100A8/A9 neutralizing antibody inhibited the effects of S100A8/A9 on fibroblasts and suppressed the progression of fibrosis in bleomycin (BLM)-induced pulmonary fibrosis mouse model. Our findings strongly suggest a crucial role of S100A8/A9 in pulmonary fibrosis and the usefulness of S100A8/A9-targeting therapy for fibrosis interstitial pneumonia. HIGHLIGHTS: S100A8/A9 level is highly upregulated in the IPF patients' lungs as well as the blood. S100A8/A9 promotes not only the growth of fibroblasts but also differentiation to myofibroblasts. The cell surface RAGE acts as a crucial receptor to the extracellular S100A8/A9 in fibroblasts. The anti-S100A8/A9 antibody effectively suppresses the progression of IPF in a mouse model. In idiopathic pulmonary fibrosis (IPF), S100A8/A9, a heterodimer composed of S100A8 and S100A9 proteins, plays a crucial role in the onset of inflammation and the subsequent formation of a feed-forward inflammatory loop that promotes fibrosis. (1) The local, pronounced increase in S100A8/A9 in the injured inflammatory lung region-which is provided mainly by the activated neutrophils and macrophages-exerts strong inflammatory signals accompanied by dozens of inflammatory soluble factors including cytokines, chemokines, and growth factors that further act to produce and secrete S100A8/A9, eventually making a sustainable inflammatory circuit that supplies an indefinite presence of S100A8/A9 in the extracellular space with a mal-increased level. (2) The elevated S100A8/A9 compels fibroblasts to activate through receptor for advanced glycation end products (RAGE), one of the major S100A8/A9 receptors, resulting in the activation of NFκB, leading to fibroblast mal-events (e.g., elevated cell proliferation and transdifferentiation to myofibroblasts) that actively produce not only inflammatory cytokines but also collagen matrices. (3) Finally, the S100A8/A9-derived activation of lung fibroblasts under a chronic inflammation state leads to fibrosis events and constantly worsens fibrosis in the lung. Taken together, these findings suggest that the extracellular S100A8/A9 heterodimer protein is a novel mainstay soluble factor for IPF that exerts many functions as described above (1-3). Against this background, we herein applied the developed S100A8/A9 neutralizing antibody to prevent IPF. The IPF imitating lung fibrosis in an IPF mouse model was effectively blocked by treatment with the antibody, leading to enhanced survival. The developed S100A8/A9 antibody, as an innovative novel biologic, may help shed light on the difficulties encountered with IPF therapy in clinical settings.

Design and synthesis of Leukotriene A4 hydrolase inhibitors to alleviate idiopathic pulmonary fibrosis and acute lung injury

Idiopathic pulmonary fibrosis (IPF) and acute lung injury (ALI) are considered two severe public health issues, attributed to malfunctions of neutrophils. They can cause chronic inflammation and have association with subsequent tissue damages. There have been rare drugs applying to the efficient treatment in clinical practice. Existing research revealed that Leukotriene B4 (LTB4) is the critical endogenous molecule to induce neutrophil inflammatory response. LTB4 blocking biosynthesis is the potential strategy treating IPF and ALI. In the present study, 45 hydroxamic acid derivatives were produced, and compound 26 was screened out as a highly selective Lead compound of Leukotriene A4 Hydrolase (LTA4H), i.e., an enzyme critical to the biosynthesis of LTB4. This compound is capable of relieving neutrophilic inflammation in an IPF mouse model at early stage, as well as mitigating LPS-induced acute lung injury via a mechanism of LTB4 blocking biosynthesis in vivo. Whether this compound acts as the potential lead compound for the treatment of IPF and ALI requires further verification.

Targeting MAP3K19 prevents human lung myofibroblast activation both in vitro and in a humanized SCID model of idiopathic pulmonary fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a disease with a devastating prognosis characterized by unrelenting lung scarring. Aberrant activation of lung fibroblasts is a key feature of this disease, yet the key pathways responsible for this are poorly understood. Mitogen-activated protein kinase, kinase, kinase- 19 (MAP3K19) was recently shown to be upregulated in IPF and this MAPK has a key role in target gene transcription in the TGF-β pathway. Herein, we further investigate the role of MAP3K19 in cultured normal and IPF fibroblasts and in a humanized SCID mouse model of IPF employing both short interfering (si) RNA and novel small-molecule inhibitors directed at this kinase. Targeting MAP3K19 had significant inhibitory effects on the expression of both alpha smooth muscle actin and extracellular matrix in cultured human IPF fibroblasts. Quantitative protein and biochemical assays, as well as histological analysis, showed that MAP3K19 was required for the development of lung fibrosis in SCID mice humanized with IPF lung fibroblasts. MAP3K19 was required for IPF myofibroblast differentiation, and targeting its activity attenuated the profibrotic activity of these cells both in vitro and in an adoptive transfer SCID model of pulmonary fibrosis.