The PDE4 inhibitor CHF6001 affects keratinocyte proliferation via cellular redox pathways

Ribociclib leverages phosphodiesterase 4 inhibition in the treatment of neutrophilic inflammation and acute respiratory distress syndrome

INTRODUCTION

Overwhelming neutrophil activation and oxidative stress significantly contribute to acute respiratory distress syndrome (ARDS) pathogenesis. However, the potential of repurposing ribociclib, a cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor used clinically in cancer treatment, for treating neutrophilic ARDS remains uncertain. This study illustrated the ability and underlying mechanism of ribociclib for treating ARDS and neutrophilic inflammation.

METHODS

Primary human neutrophils were used to determine the therapeutic effects of ribociclib on respiratory bursts, chemotactic responses, and inflammatory signaling. In vitro and silico analyses were performed to determine the underlying molecular mechanisms. The potential of ribociclib repurposing was evaluated using an in vivo ARDS model in lipopolysaccharide (LPS)-primed mice.

RESULTS

We found that treatment using ribociclib markedly limited overabundant oxidative stress (reactive oxygen species [ROS]) production and chemotactic responses (integrin levels and adhesion) in activated human neutrophils. Ribociclib was also shown to act as a selective inhibitor of phosphodiesterase 4 (PDE4), thereby promoting the cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway, leading to the inhibition of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) phosphorylation, and calcium influx. Notably, prophylactic administration and post-treatment with ribociclib ameliorated neutrophil infiltration, lung inflammation, accumulation of oxidative stress, pulmonary destruction, and mortality in mice with LPS-induced ARDS.

CONCLUSION

We demonstrated for the first time that ribociclib serves as a novel PDE4 inhibitor for treating neutrophilic inflammation and ARDS. The repurposing ribociclib and targeting neutrophilic PDE4 offer a potential off-label alternative for treating lung lesions and other inflammatory conditions.

Drug repurposing of cyclin-dependent kinase inhibitors for neutrophilic acute respiratory distress syndrome and psoriasis

BACKGROUND

Neutrophilic inflammation, characterized by dysregulated neutrophil activation, triggers a variety of inflammatory responses such as chemotactic infiltration, oxidative bursts, degranulation, neutrophil extracellular traps (NETs) formation, and delayed turnover. This type of inflammation is pivotal in the pathogenesis of acute respiratory distress syndrome (ARDS) and psoriasis. Despite current treatments, managing neutrophil-associated inflammatory symptoms remains a significant challenge.

AIM OF REVIEW

This review emphasizes the role of cyclin-dependent kinases (CDKs) in neutrophil activation and inflammation. It aims to highlight the therapeutic potential of repurposing CDK inhibitors to manage neutrophilic inflammation, particularly in ARDS and psoriasis. Additionally, it discusses the necessary precautions for the clinical application of these inhibitors due to potential off-target effects and the need for dose optimization.

KEY SCIENTIFIC CONCEPTS OF REVIEW

CDKs regulate key neutrophilic functions, including chemotactic responses, degranulation, NET formation, and apoptosis. Repurposing CDK inhibitors, originally developed for cancer treatment, shows promise in controlling neutrophilic inflammation. Clinical anticancer drugs, palbociclib and ribociclib, have demonstrated efficacy in treating neutrophilic ARDS and psoriasis by targeting off-label pathways, phosphoinositide 3-kinase (PI3K) and phosphodiesterase 4 (PDE4), respectively. While CDK inhibitors offer promising therapeutic benefits, their clinical repurposing requires careful consideration of off-target effects and dose optimization. Further exploration and clinical trials are necessary to ensure their safety and efficacy in treating inflammatory conditions.

Protein adducts with lipid peroxidation products in patients with psoriasis

Psoriasis, one of the most frequent immune-mediated skin diseases, is manifested by numerous psoriatic lessons on the skin caused by excessive proliferation and keratinization of epidermal cells. These disorders of keratinocyte metabolism are caused by a pathological interaction with the cells of the immune system, including lymphocytes, which in psoriasis are also responsible for systemic inflammation. This is accompanied by oxidative stress, which promotes the formation of lipid peroxidation products, including reactive aldehydes and isoprostanes, which are additional pro-inflammatory signaling molecules. Therefore, the presented review is focused on highlighting changes that occur during psoriasis development at the level of lipid peroxidation products, including 4-hydroxynonenal, 4-oxononenal, malondialdehyde, and acrolein, and their influence on protein structures. Furthermore, we will examine inducing agents of cellular functioning, as well as intercellular signaling. These lipid peroxidation products can form adducts with a variety of proteins with different functions in the body, including proteins within skin cells and cells of the immune system. This is especially true in autoimmune diseases such as psoriasis. For example, these changes concern proteins involved in maintaining redox homeostasis or pro-inflammatory signaling. Therefore, the formation of such adducts should attract attention, especially during the design of preventive cosmetics or anti-psoriasis therapies.

Advances in the modulation of ROS and transdermal administration for anti-psoriatic nanotherapies

Reactive oxygen species (ROS) at supraphysiological concentration have a determinate role in contributing to immuno-metabolic disorders in the epithelial immune microenvironment (EIME) of psoriatic lesions. With an exclusive focus on the gene-oxidative stress environment interaction in the EIME, a comprehensive strategy based on ROS-regulating nanomedicines is greatly anticipated to become the mainstay of anti-psoriasis treatment. This potential therapeutic modality could inhibit the acceleration of psoriasis via remodeling the redox equilibrium and reshaping the EIME. Herein, we present a marked overview of the current progress in the pathomechanisms of psoriasis, with particular concerns on the potential pathogenic role of ROS, which significantly dysregulates redox metabolism of keratinocytes (KCs) and skin-resident or -infiltrating cells. Meanwhile, the emergence of versatile nanomaterial-guided evolution for transdermal drug delivery has been attractive for the percutaneous administration of antipsoriatic therapies in recent years. We emphasize the underlying molecular mechanism of ROS-based nanoreactors for improved therapeutic outcomes against psoriasis and summarize up-to-date progress relating to the advantages and limitations of nanotherapeutic application for transdermal administration, as well as update an insight into potential future directions for nanotherapies in ROS-related skin diseases.

A transcriptomics-guided drug target discovery strategy identifies receptor ligands for lung regeneration

Currently, there is no pharmacological treatment targeting defective tissue repair in chronic disease. Here, we used a transcriptomics-guided drug target discovery strategy using gene signatures of smoking-associated chronic obstructive pulmonary disease (COPD) and from mice chronically exposed to cigarette smoke, identifying druggable targets expressed in alveolar epithelial progenitors, of which we screened the function in lung organoids. We found several drug targets with regenerative potential, of which EP and IP prostanoid receptor ligands had the most profound therapeutic potential in restoring cigarette smoke-induced defects in alveolar epithelial progenitors in vitro and in vivo. Mechanistically, we found, using single-cell RNA sequencing analysis, that circadian clock and cell cycle/apoptosis signaling pathways were differentially expressed in alveolar epithelial progenitor cells in patients with COPD and in a relevant model of COPD, which was prevented by prostaglandin E2 or prostacyclin mimetics. We conclude that specific targeting of EP and IP receptors offers therapeutic potential for injury to repair in COPD.

Oxidative Stress and Gut Microbiome in Inflammatory Skin Diseases

Oxidative stress plays a dominant role in inflammatory skin diseases. Emerging evidence has shown that the close interaction occurred between oxidative stress and the gut microbiome. Overall, in this review, we have summarized the impact of oxidative stress and gut microbiome during the progression and treatment for inflammatory skin diseases, the interactions between gut dysbiosis and redox imbalance, and discussed the potential possible role of oxidative stress in the gut-skin axis. In addition, we have also elucidated the promising gut microbiome/redox-targeted therapeutic strategies for inflammatory skin diseases.

Apremilast ameliorates IL-1α-induced dysfunction in epidermal stem cells

BACKGROUND AND PURPOSE

Skin tissue is the natural barrier that protects our body, the damage of which can be repaired by the epidermal stem cells (ESCs). However, external factors abolish the self-repair ability of ESCs by inducing oxidative stress and severe inflammation. Apremilast is a small molecular inhibitor of phosphodiesterase 4 that was approved for the treatment of psoriasis. In the present study, the protective property of Apremilast against IL-1α-induced dysfunction on epidermal stem cells, as well as the preliminary mechanism, will be investigated.

METHODS

ESCs were isolated from neonatal mice. The expression levels of TNF-α, IL-8, IL-12, MMP-2, and MMP-9 were detected using real-time PCR and ELISA. MitoSOX Red assay was used to determine the level of mitochondrial reactive oxygen species (ROS). Western blot and real-time PCR were utilized to determine the expression levels of IL-1R1, Myd88, and TRAF6. Activation of NF-κB was assessed by measuring the p-NF-κB p65 and luciferase activity. Capacities of ESCs were evaluated by measuring the gene expressions of integrin β1 and Krt19 using real-time PCR.

RESULTS

Firstly, the expression levels of TNF-α, IL-8, IL-12, MMP-2, MMP-9 and IL-1R1, as well as the ROS level, were significantly elevated by IL-1α but greatly suppressed by treatment with Apremilast. Subsequently, we found that the activated Myd88/TRAF6/NF-κB signaling pathway induced by stimulation with IL-1α was significantly inhibited by the introduction of Apremilast. As a result, Apremilast protected ESCs against IL-1α-induced impairment in capacities of ESCs, this was verified by the elevated expression levels of integrin β1 and Krt19.

CONCLUSIONS

Apremilast might ameliorate IL-1α-induced dysfunction in ESCs by mitigating oxidative stress and inflammation through inhibiting the activation of the Myd88/TRAF6/NF-κB signaling pathway.

NF-κB subunit RELA suppression of mucosa-associated lymphoid tissue lymphoma translocation protein 1 expression in oral carcinoma cells

Loss of mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1) expression closely associates with increased aggressive behaviors of oral carcinoma cells. It emphasizes that a mechanism to suppress the expression is an important subject for understanding carcinoma progression pathway. However, nothing is known at present. This study conducted on transcriptional regulation of the gene down-regulation. Reporter assays showed the presence of the silencer region between +402 and +501 region of MALT1 gene in oral carcinoma cells. It encoded a binding site of nuclear factor-κB subunit, RELA. RELA binding to the site was confirmed by the chromatin immunoprecipitation analyses, and deletion and mutations of the site significantly decreased the RELA binding. Short interfering RNAs for RELA up-regulated reporter gene and endogenous MALT1 protein expressions, and deletion and mutations of RELA binding site increased reporter gene expression. These results demonstrated RELA-binding to the site suppresses MALT1 expression that may facilitate oral carcinoma progression.

Psoriasis: pathological mechanisms, current pharmacological therapies, and emerging drug delivery systems

Psoriasis is a chronic autoimmune skin disorder triggered by either genetic factors, environmental factors, life style, or a combination thereof. Clinical investigations have identified pathogenesis, such as T cell and cytokine-mediated, genetic disposition, antimicrobial peptides, lipocalin-2, galectin-3, vaspin, fractalkine, and human neutrophil peptides in the progression of psoriasis. In addition to traditional therapies, newer therapeutics, including phosphodiesterase type 4 (PDE4) inhibitors, Janus kinase (JAK) inhibitors, monoclonal antibodies (mAbs), gene therapy, anti-T cell therapy, and phytoconstituents have been explored. In this review, we highlight nanotechnology-related developments for psoriasis treatment, including patented delivery systems and therapeutics currently in clinical trials.

DRM02, a novel phosphodiesterase-4 inhibitor with cutaneous anti-inflammatory activity

Chronic inflammatory skin disorders are frequently associated with impaired skin barrier function. Selective phosphodiesterase-4 (PDE4) inhibition constitutes an effective therapeutic strategy for the treatment of inflammatory skin diseases. We now report the pharmacological anti-inflammatory profile of DRM02, a novel pyrazolylbenzothiazole derivative with selective in vitro inhibitory activity toward PDE4 isoforms A, B and D. DRM02 treatment of cultured primary human and mouse epidermal keratinocytes interfered with pro-inflammatory cytokine production elicited by interleukin-1α and tumor necrosis factor-α. Similarly, DRM02 inhibited the production of pro-inflammatory cytokines by human peripheral blood mononuclear cells ex vivo and cultured THP-1 monocyte-like cells, with IC₅₀ values of 0.6-14 µM. These anti-inflammatory properties of DRM02 were associated with dose-dependent repression of nuclear factor-κB (NF-κB) transcriptional activity. In skin inflammation in vivo mouse models, topically applied DRM02 inhibited the acute response to phorbol ester and induced Th2-type contact hypersensitivity reactivity. Further, DRM02 also decreased cutaneous clinical changes and expression of Th17 immune pathway cytokines in a mouse model of psoriasis evoked by repeated topical imiquimod application. Thus, the overall pharmacological profiling of the PDE4 inhibitor DRM02 has revealed its potential as a topical therapy for inflammatory skin disorders and restoration of skin homeostasis.