Effect of baricitinib in regulating programmed death 1 and ligand programmed cell death ligand 1 through JAK/STAT pathway in psoriasis.

OBJECTIVES: Psoriasis is a chronic infectious skin disease triggered by an autoimmune process involving T-cell-mediated hyper-proliferation of keratinocytes. The objective of this study is to assess the modulation of programmed death 1 (PD-1) and its ligand programmed cell death ligand 1 (PD-L1) through JAK/STAT pathway during the development of a psoriasis-like disease by both in vitro and in vivo model. Baricitinib, a known inhibitor of JAK1 and JAK2, was used to study the impact on PD-1 and PD-L1. MATERIALS AND METHODS: Human peripheral blood mononuclear cells (PBMC) were stimulated with either anti-CD3/CD28 or PMA/Ionomycin, to modulate level of PD-1 and PD-L1 under psoriasis-like condition. Interferon-gamma (IFNγ) was used to treat HaCaT cells to mimic the diseased keratinocytes found in Psoriatic patients. Psoriasis was induced with Imiquimod (IMQ) in animal model to study the cross-talk between different cell types and pathways. RESULTS: Expression levels of PD-1 and PD-L1 in PBMC, and secretion of cytokines, namely tumor necrosis factor-α (TNFα), IFNγ, interleukin (IL)-6, and IL-1 ß, were down-regulated on treatment with baricitinib. Further, in IFNγ-treated HaCaT cells (keratinocytes) mRNA levels of KRT-17 and PD-L1 were up-regulated.). Interestingly, in IFNγ-treated HaCat cells baricitinib decreased the levels of inflammatory cytokines such as IL-1 ß, IL-6, and TNFα along with KRT-17 and PD-L1. On IFNγ-treatment. Data from both PBMC and HaCaT suggest an anti-inflammatory role for this compound. Accordingly, baricitinib was able to alleviate disease symptom in IMQ induce mice model of psoriasis. As a consequence of baricitinib treatment down-regulation of p-STAT3, PD- and PD-L1 expression levels were observed. CONCLUSION: This study demonstrates a crosstalk between JAK/STAT and PD-1/PD-L1 pathways. It also demonstrates that cytokines such as IFNγ and IL-17 are down-regulated by baricitinib. We believe decreased expressions of PD-1 and PD-L1 may be a consequence of baricitinib-induced down-regulation of IFNγ and IL-17. More importantly, our data from the acute model of psoriasis indicates that PD-L1 behaves as a T-cell-associated T-cell-associated surrogate activation marker rather than immunosuppressive marker in early phase of psoriasis. Therefore it does not exhibit a causal relationship to disease.

Hepatoprotective activity of Indian Phyllanthus.

CONTEXT: Phyllanthus (Euphorbiaceae) species are traditionally well-known for their medicinal properties including hepatoprotective activity. OBJECTIVE: The study assessed the hepatoprotective and antioxidant activities of 11 Phyllanthus species, P. amarus Schumach., P. urinaria L., P. debilis Klein ex Willd, P. tenellus Roxb., P. virgatus G. Forst., P. maderaspatensis L., P. reticulatus Poir., P. polyphyllus Willd., P. emblica L., P. indofischerii Bennet. and P. acidus (L.) Skeels. MATERIALS AND METHODS: The dried leaves and stems of each plant species were extracted in methanol and successively in water. The extracts were screened for hepatoprotective activity at a concentration of 50 µg/mL against tert-butyl hydroperoxide (t-BH) induced toxicity in HepG2 cells. Seven extracts from five species that showed hepatoprotective activity were assessed for their 50% effective concentration (EC50) values and their antioxidant activity using a DPPH assay. Phyllanthin and hypophyllanthin contents were also determined in these Phyllanthus species. RESULTS: The methanol extracts of P. polyphyllus, P. emblica and P. indofischeri showed high levels of hepatoprotective activity with EC50 values of 12, 19 and 28 µg/mL and IC50 of 3.77, 3.38 and 5.8 µg/mL for DPPH scavenging activity respectively against an IC50 of 3.69 µg/mL for ascorbic acid. None of these activities could be attributed to phyllanthin and hypophyllanthin. DISCUSSION AND CONCLUSION: The hepatoprotective and antioxidant activities of P. indofischeri are demonstrated for the first time in literature. The study also confirms the hepatoprotective and antioxidant activities of leaves of P. emblica and P. polyphyllus. The molecule(s) responsible for the activities is being investigated.

Modulation of lipopolysaccharide-induced pro-inflammatory mediators by an extract of Glycyrrhiza glabra and its phytoconstituents.

OBJECTIVE: To evaluate the inhibitory property of de-glycyrrhizinated extract of Glycyrrhiza glabra root and its phytoconstituents (glabridin, isoliquiritigenin and glycyrrhizin) on LPS-induced production of pro-inflammatory mediators. MATERIALS AND METHODS: Inhibitory effect of G. glabra extract and its phytoconstituents were studied on lipopolysaccharide (LPS)-induced nitric oxide (NO), interleukin-1 beta (IL-1 beta) and interleukin-6 (IL-6) levels in J774A.1 murine macrophages. RESULTS: G. glabra and isoliquiritigenin significantly inhibited LPS stimulated NO, IL-1 beta and IL-6 production. Glabridin showed significant inhibition of NO and IL-1 beta release, but failed to attenuate IL-6 levels at the tested concentrations. In addition, glycyrrhizin did not exhibit inhibitory response towards any of the LPS-induced pro-inflammatory mediators at the tested concentrations. CONCLUSION: From the results we speculate that the inhibitory effect of G. glabra extract on LPS-induced pro-inflammatory mediators is influenced by glabridin and isoliquiritigenin and is not contributed by glycyrrhizin.

Dual inhibitory effect of Glycyrrhiza glabra (GutGard™) on COX and LOX products.

Glycyrrhiza glabra and its phytoconstituents have been known to possess widespread pharmacological properties as an anti-inflammatory, anti-viral, antitumour and hepatoprotective drug. In this study, we examined the inhibitory potential of extract of G. glabra (GutGard™) root and its phytoconstituents (glabridin, glycyrrhizin, and isoliquiritigenin) on both cyclooxygenase (COX) and lipoxygenase (LOX) products in order to understand the mechanism of its anti-inflammatory action. Inhibitory effect of GutGard™ and its phytoconstituents on lipopolysaccharide (LPS) induced prostaglandin E(2) (PGE(2)), calcimycin (A23187) induced thromboxane (TXB(2)), and leukotriene (LTB(4)) release was studied using murine macrophages (J774A.1) and human neutrophil (HL-60) cells. Results revealed that, G. glabra and glabridin significantly inhibited PGE(2), TXB(2) (COX) and LTB(4) (LOX), while, isoliquiritigenin exerted inhibitory effect only against COX products but failed to suppress LOX product. However, glycyrrhizin at the tested concentrations failed to exhibit inhibitory effect on both COX and LOX products. Here, we report for the first time that G. glabra (almost devoid of glycyrrhizin) exhibits anti-inflammatory property likely through the inhibition of PGE(2), TXB(2) and LTB(4) in mammalian cell assay system, which could be influenced in part by glabridin and isoliquiritigenin.

In vitro modulation of LPS/calcimycin induced inflammatory and allergic mediators by pure compounds of Andrographis paniculata (King of bitters) extract.

The aim of the current study is to probe the anti-inflammatory/anti-allergic potential of seven phytoconstituents (andrographolide, neoandrographolide, isoandrographolide, andrograpanin, 14-deoxy-11,12-didehydroandrographolide, 7-O-methylwogonin and skullcapflavone-I) isolated from Andrographis paniculata (King of bitters) on the production of key inflammatory/allergic mediators (NO, PGE(2), IL-1 beta, IL-6, LTB(4), TXB(2) and histamine). The results demonstrated that andrographolide, isoandrographolide, 7-O-methylwogonin and skullcapflavone-I significantly inhibited LPS stimulated NO and PGE(2) release in J774A.1 macrophages. Andrographolide, isoandrographolide and 7-O-methylwogonin showed considerable inhibition of IL-1 beta production in LPS elicited macrophages. LPS induced IL-6 production was significantly inhibited by andrographolide, isoandrographolide and skullcapflavone-I in a concentration dependent manner. The results revealed that andrographolide, isoandrographolide and skullcapflavone-I significantly decreased TXB(2) release in A23187 activated HL-60 promyelocytic cells. Furthermore, the anti-allergic properties of the phytoconstituents was investigated on A23187 induced LTB(4) production (HL-60 cells) and histamine release (RBL-2H3 basophilic cells). The results showed that only skullcapflavone-I and 7-O-methylwogonin showed marked inhibitory effect on LTB(4) production, however, only 7-O-methylwogonin exerted dose-dependent inhibition towards histamine release. Therefore, this study indicates that some of these phytoconstituents exhibit potent anti-inflammatory/anti-allergic effects by modulating different inflammatory/allergic mediators. Hence, these phytoconstituents might provide useful phytomedical treatment against variety of inflammatory and allergic disorders.