Pinocembrin Reduces Keratinocyte Activation and Ameliorates Imiquimod-Induced Psoriasis-like Dermatitis in BALB/c Mice through the Heme Oxygenase-1/Signal Transducer and Activator of Transcription 3 Pathway.

Psoriasis is an autoimmune disease characterized by chronic skin inflammation and excessive keratinocyte proliferation. The itchy, scaly, and erythematous lesions present on psoriatic skin negatively affect patients' quality of life. Pinocembrin is a flavonoid present in propolis, fruits, and vegetables. It exerts neuroprotective effects and was used for treating ischemic stroke in a human clinical trial. However, the effects of pinocembrin on psoriasis have never been examined. In this study, we evaluated the effects of pinocembrin on human HaCaT keratinocytes and BALB/c mice with imiquimod- (IMQ-) induced psoriatic dermatitis. In interferon-γ- (IFN-γ-) activated HaCaT cells, pinocembrin reduced the expression of inflammatory cytokines, namely, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and keratinocyte proliferation markers, namely, keratin (K)16, K17, and Ki-67. The mechanism underlying these inhibitory effects involved the regulation of the heme oxygenase- (HO-) 1/signal transducer and activator of transcription (STAT) 3 pathway. In the IMQ-induced psoriatic dermatitis mouse model, the topical application of pinocembrin significantly ameliorated the Skin Psoriasis Area and Severity Index score, epidermal thickness, inflammation, hyperplasia, hyperkeratosis, and cluster of differentiation (CD) 4+ T-cell infiltration. Expression of the inflammatory cytokines and keratinocyte proliferation markers in dorsal skin was significantly decreased in the pinocembrin-treated group. Meanwhile, in lesional skin, the expression of HO-1 was upregulated, but that of phospho-STAT3 (pSTAT3) was downregulated. Collectively, our results indicated the therapeutic potential of pinocembrin. Additional studies are warranted to evaluate its clinical benefits in patients with psoriasis.

Alpinia oxyphylla Fruit Extract Ameliorates Experimental Autoimmune Encephalomyelitis through the Regulation of Th1/Th17 Cells.

Alpinia oxyphylla is a traditional Chinese medicine widely used for treating diarrhea, ulceration, and enuresis. Moreover, A. oxyphylla is effective for cognitive function improvement and nerve regeneration. Multiple sclerosis (MS) is a chronic neuronal inflammatory autoimmune disease that commonly affects young adults in high-latitude regions. The aim of this study was to evaluate the beneficial effects of A. oxyphylla in an experimental autoimmune encephalomyelitis (EAE) mouse model, which is an extensively used model for human MS. The ethanolic extract of A. oxyphylla fruit (AO-1) was orally administered to EAE mice. Our results showed AO-1 significantly reduced EAE symptoms. Histopathological analysis showed AO-1 reduced demyelination, inflammation, gliosis, and axonal swelling in the spinal cord. Furthermore, immunohistochemistry and quantitative polymerase chain reaction (qPCR) studies revealed that the infiltration of CD4+, CD8+ T cells, and CD11b+ monocytes into the spinal cord decreased in the AO-1-treated group. Mechanistically, the Th1 transcription factor T-bet, Th17 transcription factor retinoic acid receptor-related orphan receptor γ (RORγt), and inflammatory cytokines interferon (IFN)-γ and interleukin (IL)-17 were reduced in the spinal cords of mice treated with AO-1. The expression levels of T-bet and RORγt were also lowered in the spleens of those mice. Further in vitro study showed AO-1 inhibited production of IFN-γ, IL-2, and tumor necrosis factor-α from MOG35-55-peptide-stimulated splenocytes. One component isolated from AO-1, yakuchinone A, inhibited IL-17 production in vitro and reduced EAE symptoms in the mice. Collectively, our results indicate that AO-1 ameliorated the severity of EAE in mice and may involve the regulation of Th1/Th17 response. A. oxyphylla warrants further investigation, particularly regarding its clinical benefits for MS.

A Highly Selective Rho-Kinase Inhibitor (ITRI-E-212) Potentially Treats Glaucoma Upon Topical Administration With Low Incidence of Ocular Hyperemia.

Purpose: The purpose of this study was to investigate the IOP-lowering effects of the ITRI-E-212, a new Rho-associated protein kinase (ROCK) inhibitor. ITRI-E-212 improved fluid outflow through the trabecular meshwork and reduced IOP with transient and mild conjunctival hyperemia. ITRI-E-212 can potentially be developed into new antiglaucoma agents. Methods: ITRI-E-212 was selected from more than 200 amino-isoquinoline structures because of its adequate solubility and drug-loading percentage in eye drops. ITRI-E-212 has less than 50% inhibitory concentration (IC50) against ROCK2. The in vitro kinase inhibition was evaluated using the ADP-Glo kinase assay. A comprehensive analysis of the kinase inhibitor selectivity of ITRI-E-212 was performed using the KINOMEscan methodology. The IOP-lowering effect and tolerability of ITRI-E-212 were investigated in normotensive and ocular hypertensive rabbits. The pharmacokinetics study was performed in vivo in the aqueous humor (AH), and hyperemia was assessed. Results: ITRI-E-212 showed high in vitro inhibitory activity against ROCK2 and high specificity against AGC kinases. The mean IOP-lowering effect of ITRI-E-212 in normotensive and ocular hypertensive models was 24.9% and 28.6%, respectively; 1% ITRI-E-212 produced notable reductions in IOP that were sustained for at least 6 hours after each dose once per day. Only transient, mild hyperemia was observed. The compound extracted from the AH reached 78.4% ROCK2 kinase inhibition at 1 hour after dose administration and was sustained for 4 hours. Conclusions: ITRI-E-212 is a novel and highly specific ROCK2 inhibitor with the ability to lower IOP in animal models. It has favorable pharmacokinetic and ocular tolerability profiles with only minimal conjunctival hyperemia.