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.

PAICS ubiquitination recruits UBAP2 to trigger phase separation for purinosome assembly.

Purinosomes serve as metabolons to enhance de novo purine synthesis (DNPS) efficiency through compartmentalizing DNPS enzymes during stressed conditions. However, the mechanism underpinning purinosome assembly and its pathophysiological functions remains elusive. Here, we show that K6-polyubiquitination of the DNPS enzyme phosphoribosylaminoimidazole carboxylase and phosphoribosylaminoimidazolesuccinocarboxamide synthetase (PAICS) by cullin-5/ankyrin repeat and SOCS box containing 11 (Cul5/ASB11)-based ubiquitin ligase plays a driving role in purinosome assembly. Upon several purinosome-inducing cues, ASB11 is upregulated by relieving the H3K9me3/HP1α-mediated transcriptional silencing, thus stimulating PAICS polyubiquitination. The polyubiquitinated PAICS recruits ubiquitin-associated protein 2 (UBAP2), a ubiquitin-binding protein with multiple stretches of intrinsically disordered regions, thereby inducing phase separation to trigger purinosome assembly for enhancing DNPS pathway flux. In human melanoma, ASB11 is highly expressed to facilitate a constitutive purinosome formation to which melanoma cells are addicted for supporting their proliferation, viability, and tumorigenesis in a xenograft model. Our study identifies a driving mechanism for purinosome assembly in response to cellular stresses and uncovers the impact of purinosome formation on human malignancies.

Palbociclib blocks neutrophilic phosphatidylinositol 3-kinase activity to alleviate psoriasiform dermatitis.

BACKGROUND AND PURPOSE: Neutrophilic inflammation is a critical pathogenic factor in psoriasis. The therapeutic applicability of palbociclib, a cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitor clinically used to treat cancer, in the treatment of neutrophil-associated psoriasis remains undefined. In this study, we evaluated the therapeutic potential and pharmacological effect of palbociclib on neutrophil-associated psoriasiform dermatitis. EXPERIMENTAL APPROACH: The anti-inflammatory effects of palbociclib were determined in activated human neutrophils. The therapeutic feasibility of palbociclib in psoriasis was demonstrated in a mouse model of imiquimod-induced psoriasiform dermatitis. The in vitro enzymatic assays and in silico analyses were used to identify the underlying pharmacological mechanisms. KEY RESULTS: This study found that palbociclib inhibited neutrophilic inflammation, including superoxide anion generation, reactive oxygen species (ROS) formation, elastase degranulation and chemotactic responses. The mechanistic studies identified that the anti-inflammatory effects of palbociclib involved the targeting of phosphatidylinositol 3-kinase (PI3K) but not CDK4/6 in human neutrophils. Palbociclib preferentially targeted the p110δ catalytic subunit of PI3K and thereby blocked signalling via the PI3K/protein kinase B (Akt) pathway. Furthermore, topical application of palbociclib significantly ameliorated imiquimod-induced psoriasiform dermatitis in mice, including psoriatic symptoms, neutrophil infiltration, Akt activation and cytokine up-regulation. CONCLUSIONS AND IMPLICATIONS: This is the first study to demonstrate that palbociclib can potentially be used to treat neutrophil-associated psoriasiform dermatitis through the targeting of neutrophilic PI3K activity. Our findings prompt further research to explore the potential of palbociclib and PI3K in psoriasis and other inflammatory diseases.

An Anti-Inflammatory 2,4-Cyclized-3,4-Secospongian Diterpenoid and Furanoterpene-Related Metabolites of a Marine Sponge Spongia sp. from the Red Sea.

Chemical investigation of a Red Sea Spongia sp. led to the isolation of four new compounds, i.e., 17-dehydroxysponalactone (1), a carboxylic acid, spongiafuranic acid A (2), one hydroxamic acid, spongiafuranohydroxamic acid A (3), and a furanyl trinorsesterpenoid 16-epi-irciformonin G (4), along with three known metabolites (-)-sponalisolide B (5), 18-nor- 3,17-dihydroxy-spongia-3,13(16),14-trien-2-one (6), and cholesta-7-ene-3ß,5α-diol-6-one (7). The biosynthetic pathway for the molecular skeleton of 1 and related compounds was postulated for the first time. Anti-inflammatory activity of these metabolites to inhibit superoxide anion generation and elastase release in N-formyl-methionyl-leucyl phenylalanine/cytochalasin B (fMLF/CB)-induced human neutrophil cells and cytotoxicity of these compounds toward three cancer cell lines and one human dermal fibroblast cell line were assayed. Compound 1 was found to significantly reduce the superoxide anion generation and elastase release at a concentration of 10 µM, and compound 5 was also found to display strong inhibitory activity against superoxide anion generation at the same concentration. Due to the noncytotoxic activity and the potent inhibitory effect toward the superoxide anion generation and elastase release, 1 and 5 can be considered to be promising anti-inflammatory agents.

Aqueous Extract of Kan-Lu-Hsiao-Tu-Tan Ameliorates Collagen-Induced Arthritis in Mice by Inhibiting Oxidative Stress and Inflammatory Responses.

BACKGROUND: Kan-Lu-Hsiao-Tu-Tan (KLHTT) exhibits anti-psoriatic effects through anti-inflammatory activity in mice. However, the therapeutic effects of KLHTT on rheumatoid arthritis (RA), another significant autoimmune inflammatory disorder, have not been elucidated. Herein, we explored the anti-arthritic effects of KLHTT on collagen-induced arthritis (CIA) in mice. METHODS: KLHTT was extracted by boiling water and subjected to spectroscopic analysis. Chicken collagen type II (CII) with complete Freund's adjuvant was intradermally injected to induce CIA in DBA/1J mice. Anti-CII antibody, cytokines, malondialdehyde (MDA), and hydrogen peroxide (H2O2) were measured using ELISA, thiobarbituric acid reactive substances, and a hydrogen peroxide assay kit. Splenocyte proliferation was tested using thymidine incorporation. Th1 and Th17 cells were analyzed by flow cytometry. RESULTS: Oral KLHTT treatment (50 and 100 mg/kg) ameliorated mouse CIA by decreasing the levels of interleukin (IL)-1ß, IL-6, IL-17A, and tumour necrosis factor-α in the paw homogenates and serum. KLHTT also suppressed anti-CII antibody formation, splenocyte proliferation, and splenic Th1 and Th17 cell numbers. Additionally, KLHTT showed antioxidant activity by reducing the concentrations of MDA and H2O2 in paw tissues. CONCLUSIONS: The therapeutic effects of KLHTT in CIA mice were through regulating oxidative stress and inflammatory responses. Our results suggest that KLHTT has potential to treat RA.

Upregulation of miR-133a-3p in the Sciatic Nerve Contributes to Neuropathic Pain Development.

The micro (mi)RNAs expressed in the sciatic nerve of streptozotocin (STZ)-induced diabetic rats were evaluated in terms of their therapeutic potential in patients with diabetic neuropathic pain (DNP). Relative miRNA expression in sciatic nerve with DNP was analyzed using next-generation sequencing and quantitative PCR. Potential downstream targets of miRNAs were predicted using Ingenuity Pathway Analysis and the TargetScan database. In vitro experiments were performed using miR-133a-3p-transfected RSC96 Schwann cells. We performed micro-Western and Western blotting and immunofluorescence analyses to verify the role of miR-133a-3p. In vivo, the association between miR-133a-3p with DNP was analyzed via AAV-miR-133a-3p intraneural (intra-epineural but extrafascicular) injection into the sciatic nerve of normal rats or injection of an miR-133a-3p antagomir into the sciatic nerve of diabetes mellitus (DM) rats. miR-133a-3p mimics transfected into RSC96 Schwann cells increased VEGFR-2, p38α MAPK, TRAF-6, and PIAS3 expression and reduced NFκB p50 and MKP3 expression. In normal rats, AAV-miR-133a-3p delivery via intraneural injection into the sciatic nerve induced mechanical allodynia and p-p38 MAPK activation. In DM rats, miR-133a-3p antagomir administration alleviated DNP and downregulated p-p38 phosphorylation. Overexpression of miR-133a-3p in the sciatic nerve induced such pain. We suggest that miR-133a-3p is a potential therapeutic target for DNP.

Longitudinal Effects of an Intergenerational mHealth Program for Older Type 2 Diabetes Patients in Rural Taiwan.

PURPOSE: The purpose of the study is to test the longitudinal efficacy of a mHealth intervention (Intergenerational Mobile Technology Opportunities Program, IMTOP) for older type 2 diabetes mellitus (T2DM) patients in rural Taiwan. Few mHealth programs targeted rural older adults and the longitudinal effects are unknown. METHODS: Ninety-seven T2DM patients aged 55+ were recruited from an outpatient in Hualien, Taiwan. The intervention comprised 8-week technology and diabetes self-management training and 4-week technical support. College student tutors facilitated T2DM patients to learn technology. Participants used a diabetes self-management app to track health behaviors. Outcomes measured at baseline and at 4 and 8 months including patient-reported self-care behaviors, T2DM symptoms, clinical outcomes, health resource utilization, and medical expenditure. Linear mixed-effect regressions of repeated measures were conducted for each outcome. RESULTS: At 4 months, improvements in self-care behaviors were reported in diet, exercise, smoking, and blood glucose testing. Patients paid less endocrinology clinic visits, spent less on endocrinology medications, and improvements in fasting blood glucose and total cholesterol were observed. At 8 months, the statistical significance of improvements in diet and smoking were maintained, and the averaged endocrinology clinic visits remained less than baseline. However, more frequent occurrence of diabetes symptoms were reported at both follow-ups. CONCLUSIONS: IMTOP had lasting effects on diet and decreased smoking behavior, clinic visits, and medication costs over 8 months. Self-monitoring through an app increased awareness and may explain the increased reporting of diabetes symptoms. IMTOP is a promising model for promoting T2DM self-management in rural areas.

Bioactive Capnosanes and Cembranes from the Soft Coral Klyxum flaccidum.

Two new capnosane-based diterpenoids, flaccidenol A (1) and 7-epi-pavidolide D (2), two new cembranoids, flaccidodioxide (3) and flaccidodiol (4), and three known compounds 5 to 7 were characterized from the marine soft coral Klyxum flaccidum, collected off the coast of the island of Pratas. The structures of the new compounds were determined by extensive spectroscopic analyses, including 1D and 2D nuclear magnetic resonance (NMR) spectroscopy, and spectroscopic data comparison with related structures. The rare capnosane diterpenoids were isolated herein from the genus Klyxum for the first time. The cytotoxicity of compounds 1 to 7 against the proliferation of a limited panel of cancer cell lines was assayed. The isolated diterpenoids also exhibited anti-inflammatory activity through suppression of superoxide anion generation and elastase release in the N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLF/CB)-stimulated human neutrophils. Furthermore, 1 and 7 also exhibited cytotoxicity toward the tested cancer cells, and 7 could effectively inhibit elastase release. It is worth noting that the biological activities of 7 are reported for the first time in this paper.

Major vault protein regulates cell growth/survival signaling through oxidative modifications.

Major vault protein forms a hollow, barrel-like structure in the cell called the vault, whose functions and regulation are not well understood. The present study reports that major vault protein regulates growth/survival signaling in human airway smooth muscle cells through oxidative modifications. The promotion of protein S-glutathionylation by asthma mediators such as interleukin-22 and platelet-derived growth factor or by knocking down glutaredoxin-1 or thioredoxin activated cell growth signaling. Mass spectrometry identified that major vault protein is glutathionylated. Major vault protein knockdown enhanced cell death and inhibited STAT3 and Akt signaling. We identified a protein partner of major vault protein that is regulated by glutaredoxin-1, namely myosin-9, which was found to serve as a cell death factor. Knocking down myosin-9 or promoting protein S-glutathionylation by knocking down glutaredoxin-1 inhibited the death of airway smooth muscle cells by heating to simulate bronchial thermoplasty, a clinically successful procedure for the treatment of severe asthma. These results establish a novel signaling pathway in which ligand/receptor-mediated oxidation promotes the S-glutathionylation of major vault protein, which in turn binds to myosin-9 to suppress the heating-induced death of airway smooth muscle cells.

Platonin inhibited PDGF-BB-induced proliferation of rat vascular smooth muscle cells via JNK1/2-dependent signaling.

AIM: To examine the inhibitory actions of the immunoregulator platonin against proliferation of rat vascular smooth muscle cells (VSMCs). METHODS: VSMCs were prepared from the thoracic aortas of male Wistar rats. Cell proliferation was examined using MTT assays. Cell cycles were analyzed using flow cytometry. c-Jun N-terminal kinase (JNK)1/2, extracellular signal-regulated kinase (ERK)1/2, AKT, and c-Jun phosphorylation or p27 expression were detected using immunoblotting. RESULTS: Pretreatment with platonin (1-5 µmol/L) significantly suppressed VSMC proliferation stimulated by PDGF-BB (10 ng/mL) or 10% fetal bovine serum (FBS), and arrested cell cycle progression in the S and G(2)/M phases. The same concentrations of platonin significantly inhibited the phosphorylation of JNK1/2 but not ERK1/2 or AKT in VSMCs stimulated by PDGF-BB. Furthermore, platonin also attenuated c-Jun phosphorylation and markedly reversed the down-regulation of p27 expression after PDGF-BB stimulation. CONCLUSION: Platonin inhibited VSMC proliferation, possibly via inhibiting phosphorylation of JNK1/2 and c-Jun, and reversal of p27 down-regulation, thereby leading to cell cycle arrest at the S and G(2)/M phases. Thus, platonin may represent a novel approach for lowering the risk of abnormal VSMC proliferation and related vascular diseases.