Measurement of hypoxia in the lung in idiopathic pulmonary fibrosis: a matter of control

The translational potential of miR-26 in atherosclerosis and development of agents for its target genes ACC1/2, COL1A1, CPT1A, FBP1, DGAT2, and SMAD7

Atherosclerosis is one of the leading causes of death worldwide. miR-26 is a potential biomarker of atherosclerosis. Standardized diagnostic tests for miR-26 (MIR26-DX) have been developed, but the fastest progress has been in predicting the efficacy of IFN-α therapy for hepatocellular carcinoma (HCC, phase 3). MiR-26 slows atherosclerosis development by suppressing ACC1/2, ACLY, ACSL3/4, ALDH3A2, ALPL, BMP2, CD36, COL1A1, CPT1A, CTGF, DGAT2, EHHADH, FAS, FBP1, GATA4, GSK3β, G6PC, Gys2, HMGA1, HMGB1, LDLR, LIPC, IL-1β, IL-6, JAG2, KCNJ2, MALT1, β-MHC, NF-κB, PCK1, PLCβ1, PYGL, RUNX2, SCD1, SMAD1/4/5/7, SREBF1, TAB3, TAK1, TCF7L2, and TNF-α expression. Many agents targeting these genes, such as the ACC1/2 inhibitors GS-0976, PF-05221304, and MK-4074; the DGAT2 inhibitors IONIS-DGAT2Rx, PF-06427878, PF-0685571, and PF-07202954; the COL1A1 inhibitor HT-100; the stimulants 68Ga-CBP8 and RCT-01; the CPT1A inhibitors etomoxir, perhexiline, and teglicar; the FBP1 inhibitors CS-917 and MB07803; and the SMAD7 inhibitor mongersen, have been investigated in clinical trials. Interestingly, miR-26 better reduced intima-media thickness (IMT) than PCSK9 or CT-1 knockout. Many PCSK9 inhibitors, including alirocumab, evolocumab, inclisiran, AZD8233, Civi-007, MK-0616, and LIB003, have been investigated in clinical trials. Recombinant CT-1 was also investigated in clinical trials. Therefore, miR-26 is a promising target for agent development. miR-26 promotes foam cell formation by reducing ABCA1 and ARL4C expression. Multiple materials can be used to deliver miR-26, but it is unclear which material is most suitable for mass production and clinical applications. This review focuses on the potential use of miR-26 in treating atherosclerosis to support the development of agents targeting it.

A fibroblastic foci-targeting and hypoxia-cleavable delivery system of pirfenidone for the treatment of idiopathic pulmonary fibrosis

The progressive formation of fibroblastic foci characterizes idiopathic pulmonary fibrosis (IPF), and excessive oral doses of approved pirfenidone (PFD) always cause gastrointestinal side effects. The fibrotic response driven by activated fibroblasts could perpetuate epithelial damage and promote abnormal extracellular matrix (ECM) deposition. When modified nanoparticles reach their target, it is important to ensure a responsive release of PFD. Hypoxia is a determining factor in IPF, leading to alveolar dysfunction and deeper cellular fibrosis. Herein, a fibroblastic foci-targeting and hypoxia-cleavable drug delivery system (Fn-Azo-BSA@PEG) was established to reprogram the fibrosis in IPF. We have modified the FnBAP5 peptide to enable comprehensive fibroblastic foci targeting, which helps BSA nanoparticles recognize and accumulate at fibrotic sites. Meantime, the hypoxia-responsive azobenzene group allowed for efficient and rapid drug diffusion, while the PEGylated BSA reduced system toxicity and increased circulation in vivo. As expected, the strategy of the fibronectin-targeting-modification and hypoxia-responsive drug release synergistically inhibited activated fibroblasts and reduced the secretion of the fibrosis-related protein. Fn-Azo-BSA@PEG could accumulate in pulmonary tissue and prolong the survival time in bleomycin-induced pulmonary fibrosis mice. Together, the multivalent BSA nanoparticles offered an efficient approach for improving lung architecture and function by regulating the fibroblastic foci and hypoxia. STATEMENT OF SIGNIFICANCE: We established fibroblastic foci-targeting and hypoxia-cleavable bovine serum albumin (BSA) nanoparticles (Fn-Azo-BSA@PEG) to reprogramme the fibroblastic foci in idiopathic pulmonary fibrosis (IPF). Fn-Azo-BSA@PEG was designed to actively target fibroblasts and abnormal ECM with the FnBPA5 peptide, delivering more FDA-approved pirfenidone (PFD) to the cross-talk within the foci. Once the drug reached fibroblastic foci, the azobenzene group acted as a hypoxia-responsive linker to trigger effective and rapid drug release. Hypoxic responsiveness and FnBAP5-modification of Fn-Azo-BSA@PEG synergistically inhibited the secretion of proteins closely related to fibrogenesis. BSA's inherent transport and metabolic pathways in the pulmonary reduced the side effects of the main organs. The multivalent BSA nanoparticles efficiently inhibited IPF-fibrosis progress and preserved the lung architecture by regulating the fibroblastic foci and hypoxia.

Extracellular Lipids in the Lung and Their Role in Pulmonary Fibrosis

Lipids are major actors and regulators of physiological processes within the lung. Initial research has described their critical role in tissue homeostasis and in orchestrating cellular communication to allow respiration. Over the past decades, a growing body of research has also emphasized how lipids and their metabolism may be altered, contributing to the development and progression of chronic lung diseases such as pulmonary fibrosis. In this review, we first describe the current working model of the mechanisms of lung fibrogenesis before introducing lipids and their cellular metabolism. We then summarize the evidence of altered lipid homeostasis during pulmonary fibrosis, focusing on their extracellular forms. Finally, we highlight how lipid targeting may open avenues to develop therapeutic options for patients with lung fibrosis.