naphthoquinones and Psoriasis

Topics: Animals; Imiquimod; Lipopolysaccharides; Macrophages; Methotrexate; Mice; Naphthoquinones; Psoriasis

Psoriasis is a chronic inflammatory skin disease characterized by well‑defined scaly papules and plaques. Interleukin (IL)‑17 is involved in its pathogenesis and promotes the proliferation of epidermal keratinocytes through signal transducer and activator of transcription 3 (STAT3) activation. Shikonin, a natural naphthoquinone isolated from Lithospermum erythrorhizon, possesses anti‑inflammatory and immunosuppressive properties and can suppress IL‑17‑induced vascular endothelial growth factor expression by inhibiting the JAK/STAT3 pathway. In the present study, MTS, iCELLigence and RT‑qPCR were used to determine the optimal concentration and duration of IL‑17 or shikonin acting on HaCaT cells. The changes in the expression levels of genes associated with the IL‑6/STAT3 pathway in differentially treated cells were analyzed via RT2Profiler™ PCR Array. Small interfering RNA was used to silence the expression levels of the target gene CCAAT/enhancer‑binding protein δ (CEBPD). Western blotting and immunohistochemistry were used to evaluate the effect of shikonin on imiquimod‑induced psoriasis in mice and the expression levels of CEBPD. Shikonin reversed IL‑17‑mediated downregulation of the tumor suppressor CEBPD in HaCaT cells. Moreover, low levels of CEBPD in the imiquimod‑induced mouse model of psoriasis were restored by shikonin treatment, which ameliorated excessive keratinocyte proliferation. Taken together, these findings suggest that CEBPD plays a key role in the pathogenesis of psoriasis and can be targeted by shikonin as a potential therapeutic strategy.

Topics: Animals; CCAAT-Enhancer-Binding Protein-delta; Cell Proliferation; Disease Models, Animal; Down-Regulation; HaCaT Cells; Humans; Imiquimod; Interleukin-17; Interleukin-6; Mice; Naphthoquinones; Psoriasis; Signal Transduction; STAT3 Transcription Factor

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Cell Count; Cell Differentiation; Forkhead Transcription Factors; Immune Tolerance; Mice; Naphthoquinones; Proto-Oncogene Proteins c-akt; Psoriasis; RNA, Messenger; Skin; T-Lymphocytes, Regulatory; TOR Serine-Threonine Kinases

Shikonin is an active compound of the oriental medicinal plant, Leptospermum erythrorhizon, which has been previously shown to inhibit psoriasis-like inflammation. However, the underlying mechanism is unclear. In the present study, the mechanisms of keratinocyte proliferation and apoptosis in psoriasis in response to shikonin were explored both in vitro and in vivo. Our results showed that shikonin significantly inhibits cell proliferation and induces apoptosis in both HaCaT and LV-STAT3 HaCaT cells by targeting CEBPD, while a decrease in cell survival, proliferation and viability were found through flow-cytometry and MTS assay. Furthermore, gavage with shikonin markedly alleviated psoriasis-like manifestations in IMQ-induced BALB/c mice clinically (PASI Score) and histopathologically. Immunohistochemistry revealed that shikonin potently suppresses the JAK/STAT3 signaling pathway in local skin lesions and increases CEBPD expression. These results imply that shikonin inhibits keratinocyte proliferation and induces apoptosis, which results in psoriasis treatment through the JAK/STAT3 dependent pathway. In addition, the activation of JAK/STAT3 downregulates CEBPD in HaCaT cells and IMQ-induced BALB/c mice. However, shikonin can reverse these effects, suggesting that CEBPD may be a potential therapeutic target for psoriasis.

Topics: Animals; Apoptosis; CCAAT-Enhancer-Binding Protein-delta; Cell Line; Cell Proliferation; Humans; Imiquimod; Janus Kinases; Keratinocytes; Male; Mice, Inbred BALB C; Naphthoquinones; Psoriasis; STAT3 Transcription Factor; Up-Regulation

β,β-dimethylacryloyl alkannin (DMA) is a key component of Lithospermum and possesses good efficacy for treating psoriasis. DMA inhibits activated dendritic cells (DCs), but the mechanism is unknown. Therefore, this study aimed to explore the modulation of the TLR7/8 pathway by DMA in psoriasis-activated DCs. Models of psoriasis-like skin lesions were established using BALB/c mice; 8 mice were treated with DMA (2.5mg/kg). Bone marrow cells were isolated and induced into DCs using R848, a TLR7/8 agonist. Splenic CD11c+ cells were detected by flow cytometry. Skin CD11c+ cells were detected by immunofluorescence. TLR7, TLR8, MYD88, and IRAKM proteins were detected by Western blot. The effects of DMA on surface molecules of DCs were observed by flow cytometry. mRNA expression of inflammatory factors was detected by qRT-PCR. Secreted cytokines were detected by cytometric bead array. Compared with the model group, psoriasis-like skin lesions were alleviated by DMA, the splenic CD11c+ cells were significantly decreased (P<0.01), and CD11c+ cell numbers in skin lesions were decreased (P<0.01). Expression levels of TLR7, MYD88, and IRAKM were significantly decreased (P<0.05). R848-stimulated DCs showed increased expression of I-A/I-E, CD80, and CD86 (P<0.01), increased IL-23 and IL-1β mRNA and secretion (P<0.05), and increased TLR7, TLR8, MYD88, and IRAKM expression (P<0.01); DMA inhibited all of these effects of the TLR7/8 pathway activation by R848 (P<0.05). In conclusion, DMA could inhibit psoriasis-activated DCs via the TLR7/8 pathway.

Topics: Animals; Cell Differentiation; Cells, Cultured; Dendritic Cells; Disease Models, Animal; Humans; Imidazoles; Interleukin-1 Receptor-Associated Kinases; Interleukin-1beta; Interleukin-23; Lithospermum; Male; Membrane Glycoproteins; Mice; Mice, Inbred BALB C; Myeloid Differentiation Factor 88; Naphthoquinones; Psoriasis; Skin; Toll-Like Receptor 7; Toll-Like Receptor 8

To investigate the effect of β, β-dimethylacryloyl alkannin, a main component of Lithospermum erythrorhizon, on activated dendritic cells (DCs) in a psoriasis mouse model.. BALB/c mice were used to establish the animal model for psoriasis-like skin lesion; alkannin at 10 mg/kg (high), 5 mg/kg (medium), 2.5 mg/kg (low), respectively, were intragastrically administered. Psoriasis area and severity index (PASI) was used to evaluate the skin lesions. Histological changes, the thickness of epidermis, and the quantity of interleukin (IL)-23 in skin lesion were measured. In in vitro experiments, mononuclear cells in peripheral blood from healthy people were isolated, and monocytes were obtained. DCs with a mature state in differentiation and function were obtained through in vitro induction with several cytokines, and identified by flow cytometry. The influence of DCs on proliferation of allogenic lymphocytes was analyzed. The influence of alkannin on messenger ribonucleic acid (mRNA) expression of pro-inflammatory factors by mature DCs was evaluated using reverse transcriptase polymerase chain reaction.. Mice treated with alkannin at varying concentration showed obvious remission in psoriasis-like skin lesion compared to control group, with decreased PASI score, obviously reduced vertical thickness of epidermis. Besides, alkannin treatment decreased the expression of IL-23 in skin lesion. Alkannin (12.5 μg/mL) suppressed the ability of DCs to stimulate the proliferation of allogenic lymphocytes, and suppressed the expression and secretion of IL-6, IL-12 p40, IL-23, IL-1β, tumor necrosis factor-α mRNA and proteins, respectively.. β, β-dimethylacryloyl alkannin could suppress the function of activated DCs in imiquimod-induced psoriasis mouse model.

Topics: Aminoquinolines; Animals; Cell Proliferation; Cells, Cultured; Coculture Techniques; Cytokines; Dendritic Cells; Dermatologic Agents; Disease Models, Animal; Humans; Imiquimod; Inflammation Mediators; Lymphocyte Activation; Lymphocytes; Male; Mice, Inbred BALB C; Naphthoquinones; Psoriasis; Severity of Illness Index; Skin; Time Factors

Psoriasis is a chronic inflammatory skin disease resulting from immune dysregulation. Regulatory T cells (Tregs) are important in the prevention of psoriasis. Traditionally, reactive oxygen species (ROS) are known to be implicated in the progression of inflammatory diseases, including psoriasis, but many recent studies suggested the protective role of ROS in immune-mediated diseases. In particular, severe cases of psoriasis vulgaris have been reported to be successfully treated by hyperbaric oxygen therapy (HBOT), which raises tissue level of ROS. Also it was reported that Treg function was closely associated with ROS level. However, it has been only investigated in lowered levels of ROS so far. Thus, in this study, to clarify the relationship between ROS level and Treg function, as well as their role in the pathogenesis of psoriasis, we investigated imiquimod-induced psoriatic dermatitis (PD) in association with Treg function both in elevated and lowered levels of ROS by using knockout mice, such as glutathione peroxidase-1(-/-) and neutrophil cytosolic factor-1(-/-) mice, as well as by using HBOT or chemicals, such as 2,3-dimethoxy-1,4-naphthoquinone and N-acetylcysteine. The results consistently showed Tregs were hyperfunctional in elevated levels of ROS, whereas hypofunctional in lowered levels of ROS. In addition, imiquimod-induced PD was attenuated in elevated levels of ROS, whereas aggravated in lowered levels of ROS. For the molecular mechanism that may link ROS level and Treg function, we investigated the expression of an immunoregulatory enzyme, indoleamine 2,3-dioxygenase (IDO) which is induced by ROS, in PD lesions. Taken together, it was implied that appropriately elevated levels of ROS might prevent psoriasis through enhancing IDO expression and Treg function.

Topics: Acetylcysteine; Aminoquinolines; Animals; Dermatitis; Disease Progression; Glutathione Peroxidase; Glutathione Peroxidase GPX1; Hyperbaric Oxygenation; Imiquimod; Indoleamine-Pyrrole 2,3,-Dioxygenase; Mice, Inbred C57BL; NADPH Oxidases; Naphthoquinones; Psoriasis; Reactive Oxygen Species; T-Lymphocytes, Regulatory

A series of linearly anellated lapacho quinone analogues substituted at the 2-position of the tricyclic naphtho[2,3-b]furan-4,9-dione system were synthesized and evaluated for their ability to suppress keratinocyte hyperproliferation using HaCaT cells as the primary test system. While very good in vitro potency with IC(50) values in the submicromolar range was attained with electron-withdrawing substituents, some compounds were found to induce plasma membrane damage, as evidenced by the release of LDH activity from cytoplasm of the keratinocytes. The most potent analogue against keratinocyte hyperproliferation was the 1,2,4-oxadiazole 18, the potency of which was combined with comparably low cytotoxic membrane damaging effects. Structure-activity relationship studies with either metabolically stable or labile analogues revealed that the quinone moiety was required for activity. Selected compounds were studied in detail for their capability to generate superoxide radicals both in isolated enzymatic one- and two-electron reduction assays as well as in a HaCaT cell-based assay.

Topics: Cell Line; Cell Membrane; Cell Proliferation; Dermatologic Agents; Dicumarol; Furans; Humans; Keratinocytes; L-Lactate Dehydrogenase; NAD(P)H Dehydrogenase (Quinone); NADPH-Ferrihemoprotein Reductase; Naphthoquinones; Oxadiazoles; Psoriasis; Structure-Activity Relationship; Superoxides

A number of lapacho compounds, representing the most common constituents of the inner bark of Tabebuia impetiginosa, together with some synthetic analogues, were evaluated in vitro against the growth of the human keratinocyte cell line HaCaT. With an IC(50) value of 0.7 microM, beta-lapachone (4) displayed activity comparable to that of the antipsoriatic drug anthralin. 2-Acetyl-8-hydroxynaphtho[2,3-b]furan-4,9-dione (7), which was prepared in a four-step synthesis from 2,8-dihydroxy-1, 4-naphthoquinone, was the most potent inhibitor among the known lapacho-derived compounds and inhibited cell growth with an IC(50) value of 0.35 microM. Furthermore, other active constituents of lapacho inhibited keratinocyte growth, with IC(50) values in the range of 0.5-3.0 microM. However, as already observed with anthralin, treatment of HaCaT cells with these potent lapacho compounds also caused remarkable damage to the plasma membrane. This was documented by leakage of lactate dehydrogenase into the culture medium, which significantly exceeded that of the vehicle control. Because of their potent activity against the growth of human keratinocytes, some lapacho-derived compounds appear to be promising as effective antipsoriatic agents.

Topics: Administration, Topical; Anthralin; Anti-Inflammatory Agents; Cell Division; Cell Line; Humans; Keratinocytes; Keratolytic Agents; L-Lactate Dehydrogenase; Naphthoquinones; Psoriasis; Spectrophotometry, Infrared; Spectrophotometry, Ultraviolet

Epidermal strips, free of sebaceous gland and hair follicle contamination, were prepared from mouse tail skin. Epidermal homogenates synthesized prostaglandins and 12-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) from exogenously added [1-14C]arachidonic acid. The effects of pH, assay time, substrate concentration, and several selective inhibitors upon the lipoxygenase and cyclooxygenase pathways were determined. Ultracentrifugation of the crude homogenate at 105,000 g sedimented both activities, and pellet 12-HETE synthesis increased 2-fold relative to the crude homogenate. Recombination of the 105,000 g pellet and supernatant gave yields of prostaglandins and 12-HETE essentially equivalent to that of crude homogenate. When tested in homogenate with 4.5 microM arachidonic acid, anthralin specifically inhibited 12-HETE production with IC50 of 50.0 microM; no significant effect against cyclooxygenase was observed over the dose range of 2-200 microM. 1,8-Dihydroxy-9,10-anthraquinone (DHAQ) also specifically inhibited 12-HETE synthesis, but the dose response curve was flatter and maximum inhibition was only 55% at 200 microM. 6-Chloro-2,3-dihydroxy-1,4-naphthoquinone (CDNQ), an agent with topical antipsoriatic activity, also inhibited 12-HETE synthesis with an IC50 of 25 microM, but simultaneously stimulated prostaglandin production, up to 2.5-fold at 200 microM. When tested with washed human platelets, anthralin again specifically inhibited 12-HETE production with an IC50 of 10 microM, while DHAQ inhibited lipoxygenase activity by only 40% at 25 microM. When tested in platelets, CDNQ gave 33% inhibition of 12-HETE production at 200 microM, although prostaglandin synthesis was stimulated over the range of 25-200 microM. It is proposed that certain antipsoriatic agents may exert their action through modulation of arachidonic acid metabolism.

Topics: Animals; Anthracenes; Anthralin; Anthraquinones; Arachidonate Lipoxygenases; Arachidonic Acid; Arachidonic Acids; Blood Platelets; Cyclooxygenase Inhibitors; Epidermis; Female; Humans; Lipoxygenase Inhibitors; Male; Mice; Naphthoquinones; Prostaglandin-Endoperoxide Synthases; Psoriasis