Biomimetic lipid Nanocomplexes incorporating STAT3-inhibiting peptides effectively infiltrate the lung barrier and ameliorate pulmonary fibrosis

Revolutionizing the Treatment of Idiopathic Pulmonary Fibrosis: From Conventional Therapies to Advanced Drug Delivery Systems

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive interstitial lung disease that has been well-reported in the medical literature. Its incidence has risen, particularly in light of the recent COVID-19 pandemic. Conventionally, IPF is treated with antifibrotic drugs-pirfenidone and nintedanib-along with other drugs for symptomatic treatments, including corticosteroids, immunosuppressants, and bronchodilators based on individual requirements. Several drugs and biologicals such as fluorofenidone, thymoquinone, amikacin, paclitaxel nifuroxazide, STAT3, and siRNA have recently been evaluated for IPF treatment that reduces collagen formation and cell proliferation in the lung. There has been a great deal of research into various treatment options for pulmonary fibrosis using advanced delivery systems such as liposomal-based nanocarriers, chitosan nanoparticles, PLGA nanoparticles, solid lipid nanocarriers, and other nanoformulations such as metal nanoparticles, nanocrystals, cubosomes, magnetic nanospheres, and polymeric micelles. Several clinical trials are also ongoing for advanced IPF treatments. This article elaborates on the pathophysiology of IPF, its risk factors, and different advanced drug delivery systems for treating IPF. Although extensive preclinical data is available for these delivery systems, the clinical performance and scale-up studies would decide their commercial translation.

Inhaled nanoparticles for treating idiopathic pulmonary fibrosis by inhibiting honeycomb cyst and alveoli interstitium remodeling

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with high mortality. The Food and Drug Administration-approved drugs, nintedanib and pirfenidone, could delay progressive fibrosis by inhibiting the overactivation of fibroblast, however, there was no significant improvement in patient survival due to low levels of drug accumulation and remodeling of honeycomb cyst and interstitium surrounding the alveoli. Herein, we constructed a dual drug (verteporfin and pirfenidone)-loaded nanoparticle (Lip@VP) with the function of inhibiting airway epithelium fluidization and fibroblast overactivation to prevent honeycomb cyst and interstitium remodeling. Specifically, Lip@VP extensively accumulated in lung tissues via atomized inhalation. Released verteporfin inhibited the fluidization of airway epithelium and the formation of honeycomb cyst, and pirfenidone inhibited fibroblast overactivation and reduced cytokine secretion that promoted the fluidization of airway epithelium. Our results indicated that Lip@VP successfully rescued lung function through inhibiting honeycomb cyst and interstitium remodeling. This study provided a promising strategy to improve the therapeutic efficacy for IPF.

Mefloquine improves pulmonary fibrosis by inhibiting the KCNH2/Jak2/Stat3 signaling pathway in macrophages

Idiopathic pulmonary fibrosis (IPF) is a life-threatening disease characterized by severe pulmonary fibrosis, for which there is an urgent need for effective therapeutic agents. Mefloquine (Mef) is a quinoline compound primarily used for the treatment of malaria. However, high doses (>25 mg/kg) may lead to side effects such as cardiotoxicity and psychiatric disorders. Here, we found that low-dose Mef (5 mg/kg) can safely and effectively treat IPF mice. Functionally, Mef can improve the pulmonary function of IPF mice (PIF, PEF, EF50, VT, MV, PENH), alleviating pulmonary inflammation and fibrosis by inhibiting macrophage activity. Mechanically, Mef probably regulates the Jak2/Stat3 signaling pathway by binding to the 492HIS site of Potassium voltage-gated channel subfamily H member 2 (KCNH2) protein in macrophages, inhibiting the secretion of macrophage inflammatory and fibrotic factors. In summary, Mef may inhibit macrophage activity by binding to KCNH2 protein, thereby slowing down the progress of IPF.

Nanoengineered mesenchymal stem cell therapy for pulmonary fibrosis in young and aged mice

Pulmonary fibrosis (PF) is an age-related interstitial lung disease that results in notable morbidity and mortality. The Food and Drug Administration-approved drugs can decelerate the progression of PF; however, curing aged patients with severe fibrosis is ineffective because of insufficient accumulation of these drugs and wide necrocytosis of type II alveolar epithelial cells (AEC IIs). Here, we constructed a mesenchymal stem cell (MSC)-based nanoengineered platform via the bioconjugation of MSCs and type I collagenase-modified liposomes loaded with nintedanib (MSCs-Lip@NCAF) for treating severe fibrosis. Specifically, MSCs-Lip@NCAF migrated to fibrotic lungs because of the homing characteristic of MSCs and then Lip@NCAF was sensitively released. Subsequently, Lip@NCAF ablated collagen fibers, delivered nintedanib into fibroblasts, and inhibited fibroblast overactivation. MSCs differentiated into AEC IIs to repair alveolar structure and ultimately promote the regeneration of damaged lungs in aged mice. Our findings indicated that MSCs-Lip@NCAF could be used as a promising therapeutic candidate for PF therapy, especially in aged patients.

Inhaled nano-based therapeutics for pulmonary fibrosis: recent advances and future prospects

It is reported that pulmonary fibrosis has become one of the major long-term complications of COVID-19, even in asymptomatic individuals. Currently, despite the best efforts of the global medical community, there are no treatments for COVID-induced pulmonary fibrosis. Recently, inhalable nanocarriers have received more attention due to their ability to improve the solubility of insoluble drugs, penetrate biological barriers of the lungs and target fibrotic tissues in the lungs. The inhalation route has many advantages as a non-invasive method of administration and the local delivery of anti-fibrosis agents to fibrotic tissues like direct to the lesion from the respiratory system, high delivery efficiency, low systemic toxicity, low therapeutic dose and more stable dosage forms. In addition, the lung has low biometabolic enzyme activity and no hepatic first-pass effect, so the drug is rapidly absorbed after pulmonary administration, which can significantly improve the bioavailability of the drug. This paper summary the pathogenesis and current treatment of pulmonary fibrosis and reviews various inhalable systems for drug delivery in the treatment of pulmonary fibrosis, including lipid-based nanocarriers, nanovesicles, polymeric nanocarriers, protein nanocarriers, nanosuspensions, nanoparticles, gold nanoparticles and hydrogel, which provides a theoretical basis for finding new strategies for the treatment of pulmonary fibrosis and clinical rational drug use.

Enhancement of suppression oxidative stress and inflammation of quercetin by nano-decoration for ameliorating silica-induced pulmonary fibrosis

Silicosis is a life-threatening lung fibrotic disease caused by excessive inhalation of environmental exposure to crystalline silica-containing dust, whereas achieving therapeutic cures are constrained. Antioxidation and anti-inflammation are currently recognized as effective strategies to counteract organ fibrosis. Using naturally occurring phytomedicines quercetin (Qu) has emerged in antagonizing fibrotic disorders involving oxidative stress and inflammation, but unfortunately the hydrophilicity deficiency. Herein, chitosan-assisted encapsulation of Qu in nanoparticles (Qu/CS-NPs) was first fabricated for silicosis-associated fibrosis treatment by pulmonary delivery. Qu/CS-NPs with spherical diameters of ~160 nm, demonstrated a high Qu encapsulated capability, excellent hydrophilic stability, fantastic oxidation radical scavenging action, and outstanding controlled as well as slow release Qu action. A silicosis rat model induced by intratracheal instillation silica was established to estimate the anti-fibrosis effect of Qu/CS-NPs. After intratracheal administration, CS-NPs markedly enhanced Qu anti-fibrotic therapy efficacy, accompanying the evident changes in reducing ROS and MDA production to mitigate oxidative stress, inhibiting IL-1β and TNF-α release, improving lung histological architecture, down-regulating α-SAM levels and suppressing ECM deposition, and thereby ameliorating silica-induced pulmonary fibrosis. Results manifested that the augmented antioxidant and anti-inflammatory activities of Qu by CS-NPs delivery was a result of achieving this remarkable improvement in curative effects. Combined with negligible systemic toxicity, nano-decorated Qu may provide a feasible therapeutic option for silicosis therapy.

Engineering and Modeling the Lung Mesenchyme

The structure of the mammalian lung controls the flow of air through the airways and into the distal alveolar region where gas exchange occurs. Specialized cells in the lung mesenchyme produce the extracellular matrix (ECM) and growth factors required for lung structure. Historically, characterizing the mesenchymal cell subtypes was challenging due to their ambiguous morphology, overlapping expression of protein markers, and limited cell-surface molecules needed for isolation. The recent development of single-cell RNA sequencing (scRNA-seq) complemented with genetic mouse models demonstrated that the lung mesenchyme comprises transcriptionally and functionally heterogeneous cell-types. Bioengineering approaches that model tissue structure clarify the function and regulation of mesenchymal cell types. These experimental approaches demonstrate the unique abilities of fibroblasts in mechanosignaling, mechanical force generation, ECM production, and tissue regeneration. This chapter will review the cell biology of the lung mesenchyme and experimental approaches to study their function.

Pathological collagen targeting and penetrating liposomes for idiopathic pulmonary fibrosis therapy

Idiopathic pulmonary fibrosis (IPF) is a fibrotic interstitial lung disease in which collagen progressively deposits in the supporting framework of the lungs. The pathological collagen creates a recalcitrant barrier in mesenchyme for drug penetration, thus greatly restricting the therapeutical efficacy. On the other hand, this overloaded collagen is gradually exposed to the bloodstream at fibrotic sites because of the vascular hyperpermeability, thus serving as a potential target. Herein, pathological collagen targeting and penetrating liposomes (DP-CC) were constructed to deliver anti-fibrotic dual drugs including pirfenidone (PFD) and dexamethasone (DEX) deep into injured alveoli. The liposomes were co-decorated with collagen binding peptide (CBP) and collagenase (COL). CBP could help vehicle recognize the pathological collagen and target the fibrotic lungs efficiently because of its high affinity to collagen, and COL assisted in breaking through the collagen barrier and delivering vehicle to the center of injured sites. Then, the released dual drugs developed a synergistic anti-fibrotic effect to repair the damaged epithelium and remodel the extracellular matrix (ECM), thus rebuilding the lung architecture. This study provides a promising strategy to deliver drugs deep into pathological collagen accumulated sites for the enhanced treatment of IPF.

Combination of a STAT3 inhibitor with anti-PD-1 immunotherapy is an effective treatment regimen for a vemurafenib-resistant melanoma

Patients with BRAF^V600E-mutant melanoma are effectively treated with the BRAF-inhibiting drug, vemurafenib, but soon develop drug resistance, limiting vemurafenib’s therapeutic efficacy. Constitutive activation of STAT3 in cancer cells and immune cells in the tumor microenvironment (TME) is a crucial contributor to the development of drug resistance and immune evasion in most cancers. Here, we investigated the antitumor efficacy and TME remodeling by APT_STAT3-9R, a cell-permeable STAT3 inhibitory peptide, as a strategy to treat vemurafenib-resistant melanoma. We found that vemurafenib-resistant melanoma remodels into immunosuppressive TME by increasing the expression of specific chemokines to facilitate the infiltration of immunosuppressive immune cells, such as myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs). Intratumoral treatment of APT_STAT3-9R led to a reduction in the population of MDSCs and TAMs, while increasing infiltration of cytotoxic T lymphocytes in the TME. Moreover, combination therapy with APT_STAT3-9R and an anti-PD-1 antibody enhanced significant suppression of tumor growth by decreasing infiltration of these immunosuppressive immune cells while increasing the infiltration and cytotoxicity of CD8⁺ T cells. These findings suggest that combined blockade of STAT3 and PD-1 signaling pathways may be an effective treatment option for overcoming poor therapeutic outcomes associated with drug-resistant BRAF-mutant melanoma.

Novel drug delivery systems and disease models for pulmonary fibrosis

Pulmonary fibrosis (PF) is a serious and progressive lung disease which is possibly life-threatening. It causes lung scarring and affects lung functions including epithelial cell injury, massive recruitment of immune cells and abnormal accumulation of extracellular matrix (ECM). There is currently no cure for PF. Treatment for PF is aimed at slowing the course of the disease and relieving symptoms. Pirfenidone (PFD) and nintedanib (NDNB) are currently the only two FDA-approved oral medicines to slow down the progress of idiopathic pulmonary fibrosis, a specific type of PF. Novel drug delivery systems and therapies have been developed to improve the prognosis of the disease, as well as reduce or minimize the toxicities during drug treatment. The drug delivery routes for these therapies are various including oral, intravenous, nasal, inhalant, intratracheal and transdermal; although this is dependent on specific treatment mechanisms. In addition, researchers have also expanded current animal models that could not fully restore the clinicopathology, and developed a series of in vitro models such as organoids to study the pathogenesis and treatment of PF. This review describes recent advances on pathogenesis exploration, classifies and specifies the progress of drug delivery systems by their delivery routes, as well as an overview on the in vitro and in vivo models for PF research.

Ameliorative Effect of Citrus junos Tanaka Waste (By-Product) Water Extract on Particulate Matter 10-Induced Lung Damage

Citrus junos Tanaka (CJ)-related products are well-accepted by consumers worldwide; thus, they generate huge amounts of waste (peel, pulp, and seed) through CJ processing. Although some CJ by-products (CJBs) are recycled, their use is limited owing to the limited understanding of their nutritional and economic value. The exposure to particulate matter (PM) increases the risk of respiratory diseases. In this study, we investigated the ameliorative effects of CJB extracts (100, 200 mg/kg/day, 7 days) on PM10-induced (10 mg/kg, intranasal, 6 h) lung damage in BALB/c mice. Cell type-specific signaling pathways are examined using the A549 (PM10, 200 μg/mL, 6 h) and RAW264.7 (LPS, 100 ng/mL, 6 h) cell lines. The CJB extracts significantly attenuated PM10-induced pulmonary damage and inflammatory cell infiltration in a mouse model. The essential protein markers in inflammatory signaling pathways, such as AKT, ERK, JNK, and NF-κB for PM10-induced phosphorylation, were dramatically reduced by CJB extract treatment in both the mouse and cell models. Furthermore, the CJB extracts reduced the production of reactive oxygen species and nitric oxide in a dose-dependent manner in the cells. Comprehensively, the CJB extracts were effective in reducing PM10-induced lung injuries by suppressing pulmonary inflammation, potentially due to their anti-inflammatory and antioxidant properties.

Advances in lipid-based pulmonary nanomedicine for the management of inflammatory lung disorders

Inflammatory lung disorders have become one of the fastest growing global healthcare concerns, with more than 500 million annual cases of disorders such as chronic obstructive pulmonary disease, asthma and pulmonary fibrosis. Owing to environmental changes and socioeconomic disparity, the numbers are expected to grow even more in years to come. The therapeutic strategies and approved drugs currently employed in the management of inflammatory lung disorders show dose-dependent resistance and pharmacokinetic limitations. This review comprehensively discusses lipid-based pulmonary nanomedicine as a potential platform to overcome these barriers while ensuring site-specific drug delivery and minimal side effects in nontargeted tissues for the management of noninfectious inflammatory lung disorders.

Inhalable cryptotanshinone spray-dried swellable microparticles for pulmonary fibrosis therapy by regulating TGF-β1/Smad3, STAT3 and SIRT3 pathways

Cryptotanshinone (CTS) is a promising therapeutic option for pulmonary fibrosis (PF). However, clinical applications of CTS are limited owing to high photosensitivity and poor oral bioavailability. Pulmonary drug delivery, especially sustained pulmonary drug delivery, is promising for local treatment of chronic lung diseases. In this study, CTS was encapsulated in an optimized chitosan/L-leucine-based swellable microparticles (SMs) system, which exhibited an appropriate aerosolization performance, sustained release and storage stability. SMs enhanced the in vitro anti-fibrosis efficacy of CTS as shown by the improved cellular uptake. The effect of PF status on in vivo fate of the pulmonary delivered drug was also assessed. Pharmacokinetics and tissue distribution of oral and pulmonary delivery CTS in bleomycin-induced PF rats were compared. Pulmonary delivery exhibited high drug concentrations in pulmonary lesion areas, with reduced exposure to blood and non-targeted tissues after administration at a significantly lower dose compared with oral delivery. Moreover, PF pathological status enhanced activity of SMs, implying that pulmonary delivery was highly effective for PF treatment. Compared to oral delivery, Inhaled SMs showed comparable or even better efficacies at approximately 60-fold low dose compared with oral delivery. A sustained efficacy was observed under a prolonged administration interval (corresponding to half the total dose). Inhalation safety of SMs was established, and important mechanism-related signaling pathways against PF were investigated in vitro and in vivo. In summary, the findings showed that the developed CTS-loaded sustained pulmonary delivery system is a safe and effective strategy for chronic PF treatment.

Dihydroartemisinin attenuates pulmonary inflammation and fibrosis in rats by suppressing JAK2/STAT3 signaling

Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, has induced a worldwide pandemic since early 2020. COVID-19 causes pulmonary inflammation, secondary pulmonary fibrosis (PF); however, there are still no effective treatments for PF. The present study aimed to explore the inhibitory effect of dihydroartemisinin (DHA) on pulmonary inflammation and PF, and its molecular mechanism. Morphological changes and collagen deposition were analyzed using hematoxylin-eosin staining, Masson staining, and the hydroxyproline content. DHA attenuated early alveolar inflammation and later PF in a bleomycin-induced rat PF model, and inhibited the expression of interleukin (IL)-1β, IL-6, tumor necrosis factor α (TNFα), and chemokine (C-C Motif) Ligand 3 (CCL3) in model rat serum. Further molecular analysis revealed that both pulmonary inflammation and PF were associated with increased transforming growth factor-β1 (TGF-β1), Janus activated kinase 2 (JAK2), and signal transducer and activator 3(STAT3) expression in the lung tissues of model rats. DHA reduced the inflammatory response and PF in the lungs by suppressing TGF-β1, JAK2, phosphorylated (p)-JAK2, STAT3, and p-STAT3. Thus, DHA exerts therapeutic effects against bleomycin-induced pulmonary inflammation and PF by inhibiting JAK2-STAT3 activation. DHA inhibits alveolar inflammation, and attenuates lung injury and fibrosis, possibly representing a therapeutic candidate to treat PF associated with COVID-19.

Biomedical Applications of a Novel Class of High-Affinity Peptides

Most therapeutic peptides available on the market today are naturally occurring hormones or protein fragments that were serendipitously discovered to possess therapeutic effects. However, the limited repertoire of available natural resources presents difficulties for the development of new peptide drug candidates. Traditional peptides possess several shortcomings that must be addressed for biomedical applications, including relatively low affinity or specificity toward biological targets compared to antibody- and protein scaffold-based affinity molecules, poor in vivo stability owing to rapid enzymatic degradation, and rapid clearance from circulation owing to their small size. Going forward, it will be increasingly important for scientists to develop novel classes of high-affinity and -specificity peptides against desired targets that mitigate these limitations while remaining compatible with pharmaceutical manufacturing processes. Recently, several highly constrained, artificial cyclic peptides have emerged as platforms capable of generating high-affinity peptide binders against various disease-associated protein targets by combining with phage or mRNA display method, some of which have entered clinical trials. In contrast, although linear peptides are relatively easy to synthesize cost-effectively and modify site-specifically at either N- or C-termini compared to cyclic peptides, there have been few linear peptide-based platforms that can provide high-affinity and -specificity peptide binders.In this Account, we describe the creation and development of a novel class of high-affinity peptides, termed "aptide"-from the Latin word "aptus" meaning "to fit" and "peptide"-and summarize their biomedical applications. In the first part, we consider the design and creation of aptides, with a focus on their unique structural features and binding mode, and address screening and identification of target protein-specific aptides. We also discuss advantages of the aptide platform over ordinary linear peptides lacking preorganized structures in terms of the affinity and specificity of identified peptide binders against target molecules. In the second part, we describe the potential biomedical applications of various target-specific aptides, ranging from imaging and therapy to theranostics, according to the types of aptides and diseases. We show that certain aptides can not only bind to a target protein but also inhibit its biological function, thereby showing potential as therapeutics per se. Further, aptides specific for cancer-associated protein antigens can be used as escort molecules or targeting ligands for delivery of chemotherapeutics, cytokine proteins, and nanomedicines, such as liposomes and magnetic particles, to tumors, thereby substantially improving therapeutic effects. Finally, we present a strategy capable of overcoming the critical issue of short blood circulation time associated with most peptides by constructing a hybrid system between an aptide and a hapten cotinine-specific antibody.