Plumbagin rescues the granulosa cell's pyroptosis by reducing WTAP-mediated N6-methylation in polycystic ovary syndrome.

The survival of ovary granulosa cells (GC) is critical in the initiation and progression of polycystic ovary syndrome (PCOS) in females. Here, we found that the PCOS process is accompanied by massive GC pyroptosis resulting from Caspase-1 inflammasome activation. Administration of plumbagin, an effective compound isolated from plant medicine, can prevent the pyroptosis of GC and the onset of PCOS. Mechanistic study indicates the over-activation of the inflammasome in GC is due to the upregulation of WTAP, a key regulator of the RNA N6-methylase complex. WTAP mediates the mRNA N6-methylation of NLRP3 inflammasome component ASC and enhances ASC RNA stability, which results in the overactivation of the inflammasome in GCs from the PCOS model. Plumbagin treatment suppresses the WTAP-mediated N6-methylation of ASC mRNA and reduces the pyroptosis of GCs. This study supports the profound potential of plumbagin in PCOS treatment.

Acquired diffuse slate-grey facial dyspigmentation due to henna: an unrecognized cause of pigment contact dermatitis in Korean patients.

Henna is a vegetable hair dye that can be used by individuals who are sensitized to oxidative dyes due to low allergenicity. The reported incidence of slate-grey facial dyspigmentation following the use of henna hair dye is extremely rare. This study aimed to identify the clinical, dermoscopic, and histopathological features of slate-grey facial dyspigmentation following the use of henna hair dye in Korean patients. We identified all patients who presented with slate-grey facial dyspigmentation following usage of henna hair dye. Patients were further evaluated for clinical, dermoscopic, and histopathological findings along with their patch test results. All 11 patients were females with Fitzpatrick's skin phototype III or IV. Prominent slate-grey-coloured dyspigmentation on the lateral side of the face and neck was most common in eight (72%) patients. Under dermoscopic examination, a pseudo-network with grey dots was observed in all patients. Histopathological examination revealed liquefaction degeneration of the epidermal basal layer and pigmentary incontinence in the papillary dermis in all patients. The diagnosis of pigmented contact dermatitis following usage of henna was made based on the clinical, dermoscopic, and histopathological findings in all patients. Pigmented contact dermatitis associated with henna occurs mostly in middle-aged women and requires long-term treatment. Therefore, careful attention should be paid when henna is used to dye hair in this age group.

Immunogenicity of mammary tumor cells can be induced by shikonin via direct binding-interference with hnRNPA1.

Immunogenic cell death (ICD) of tumor cells occurs via various pathways that activate immune cell systems against cancer. Previous studies have demonstrated that shikonin (SK), a plant secondary metabolite, can confer strong pharmacological activities that activate ICD and strong immunogenicity of tumor cells. However, the exact hierarchical regulatory mechanisms including the molecular targets of SK-activated immunogenicity are still unknown. Here, the heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) was revealed to serve as a specific protein target for SK. This binding plays a key role in SK-stimulated ICD activity and the suppression of post-transcriptional mRNA processing, including nuclear export activity of newly synthesized mRNAs in mammary carcinoma cells in vitro. Moreover, it also mechanistically mediates the anti-metastatic effect of a tumor cell lysate (TCL) vaccine, which can be readily generated from SK-treated 4T1 tumor cells (SK-TCL), and the derived tumor-immunogenicity of SK-TCL-treated dendritic cells in vivo. Together, the identification of hnRNPA1 as the intracellular molecular target provides compelling pharmacology-based knowledge for the potential clinical use of SK-induced immunogenicity. In addition, SK may also serve as a potent suppressor that interferes with specific post-transcriptional activities, a mechanism which may be useful for exploitation in cancer therapeutics.

Ex vivo effects of naphthoquinones on allergen-sensitized mononuclear cells in mice.

Naphthoquinone (NQ), one of the extractable chemical compounds of diesel exhaust particles, enhances allergic asthma traits in mice. However, it remains unknown whether: (1) several types of NQs have the same potential to facilitate allergies; and (2) NQs synergistically disrupt the functional phenotypes of immune cells. The aim of the present study was to investigate the effects of two types (1,2- and 1,4-) of NQs on sensitized mononuclear cells using an ex vivo assay. Male BALB/c mice were repeatedly and intraperitoneally administered ovalbumin (OVA: 20 µg) plus alum with or without two different doses of each NQ. After the final administration, splenocytes (mononuclear cells) were isolated from these mice and cultured in the presence of OVA. Helper T-related cytokines in the culture supernatants and downstream molecules were then evaluated. Protein levels of interferon-γ were higher in the supernatants from 1,2-NQ and 1,4-NQ at low dose + OVA-exposed mononuclear cells following the OVA stimulation than in those from OVA-exposed mononuclear cells. Interleukin (IL)-13 levels were higher in the supernatants from low dose NQs + OVA-exposed mononuclear cells. IL-17 levels were significantly higher in the supernatants from low dose 1,2-NQ + OVA-exposed mononuclear cells. The quantity of phosphorylated STAT6 in the nuclei of these cells was significantly greater in the low dose NQ + OVA groups than in the OVA group. These findings suggest NQs differently enhance allergen sensitization in the context of the Th response against mononuclear cells such as lymphocytes.

A method for detecting covalent modification of sensor proteins associated with 1,4-naphthoquinone-induced activation of electrophilic signal transduction pathways.

While metabolic activation of naphthalene, yielding 1,2-naphthoquinone (1,2-NQ) and 1,4-NQ that can covalently bind to cellular proteins, has been recognized to be associated with its toxicity, the current consensus is that such electrophile-mediated covalent modification of sensor proteins with thiolate ions is also involved in activation of cellular signal transduction pathways for cellular protection against reactive materials. In the present study, we developed an immunochemical assay to detect cellular proteins adducted by 1,4-NQ. Dot blot analysis indicated that the antibody prepared against 1,4-NQ recognized the naphthalene moiety with the para-dicarbonyl group, rather than with the ortho-dicarbonyl group. Furthermore, little cross-reactivity of para-quinones with either a different number of aromatic rings (n = 1) or substituent groups was observed. With this specific antibody against 1,4-NQ, we identified nine target proteins of 1,4-NQ following exposure of human epithelial carcinoma cell line A431 to 1,4-NQ. Among them, heat shock protein 90 (HSP90) and HSP70 are of interest because covalent modification of these chaperones causes activation of heat shock factor-1, which plays a role in the cellular response against electrophiles such as 1,4-NQ. Thus, our method, which does not use radiolabeled compounds, would be applicable for exploring activation of electrophilic signal transduction pathways coupled to covalent modification of sensor proteins during exposure to naphthalene as well as 1,4-NQ.

[Enhancing the immunogenic activity of influvac vaccine in the use of adjuvant TI complexes modified by echinochrome A].

The self-assembly of marine macrophyte glycolipids, holothurian saponin, and cholesterol gave rise to nanoscale morphological structures called tubular immunostimulating (TI) complexes. Whether the latter could be used on the basis of vaccine preparations containing the influenza virus subunit antigens was studied. There was an obvious increase in the immunogenicity of influenza virus hemagglutinin when the experimental animals were immunized with this antigen as part of TI complexes. It was shown that the adjuvant activity of the TI complex to influenza virus hemagglutinin could be enhanced by adding the known antioxidant echinochrome A from a sand-dollar (Echinarachnius parma) to the matrix of the TI complex.

Modulation of plumbagin production in Plumbago zeylanica using a single-chain variable fragment antibody against plumbagin.

A single-chain variable fragment antibody (scFv) against plumbagin (PL) accumulated the PL production in the hairy roots of Plumbago zeylanica. Recombinant Agrobacterium rhizogenes (ATCC 15834) containing an scFv gene against PL (PL-scFv) were obtained through triparental mating and transformed into P. zeylanica to induce PL-scFv protein in the hairy roots. Up to 40 µg recombinant PL-scFv were expressed per milligram of soluble protein in transgenic P. zeylanica hairy root cultures. The mean PL content obtained from transgenic hairy roots (12.24 µg/100 mg dry weight) exhibited 2.2 times higher than those obtained from wild-type (5.48 µg/100 mg dry weight). The high correlation between the PL-scFv expression level and PL content of the recombinant plants suggested that the PL biosynthesis pathway had been modulated by the expression of PL-scFv protein in the hairy roots of P. zeylanica.

Linking oxidative events to inflammatory and adaptive gene expression induced by exposure to an organic particulate matter component.

BACKGROUND: Toxicological studies have correlated inflammatory effects of diesel exhaust particles (DEP) with its organic constituents, such as the organic electrophile 1,2-naphthoquinone (1,2-NQ). OBJECTIVE: To elucidate the mechanisms involved in 1,2-NQ-induced inflammatory responses, we examined the role of oxidant stress in 1,2-NQ-induced expression of inflammatory and adaptive genes in a human airway epithelial cell line. METHODS: We measured cytosolic redox status and hydrogen peroxide (H2O2) in living cells using the genetically encoded green fluorescent protein (GFP)-based fluorescent indicators roGFP2 and HyPer, respectively. Expression of interleukin-8 (IL-8), cyclooxygenase-2 (COX-2), and heme oxygenase-1 (HO-1) mRNA was measured in BEAS-2B cells exposed to 1,2-NQ for 1-4 hr. Catalase overexpression and metabolic inhibitors were used to determine the role of redox changes and H2O2 in 1,2-NQ-induced gene expression. RESULTS: Cells expressing roGFP2 and HyPer showed a rapid loss of redox potential and an increase in H2O2 of mitochondrial origin following exposure to 1,2-NQ. Overexpression of catalase diminished the H2O2-dependent signal but not the 1,2-NQ-induced loss of reducing potential. Catalase overexpression and inhibitors of mitochondrial respiration diminished elevations in IL-8 and COX-2 induced by exposure to 1,2-NQ, but potentiated HO-1 mRNA levels in BEAS cells. CONCLUSION: These data show that 1,2-NQ exposure induces mitochondrial production of H2O2 that mediates the expression of inflammatory genes, but not the concurrent loss of reducing redox potential in BEAS cells. 1,2-NQ exposure also causes marked expression of HO-1 that appears to be enhanced by suppression of H2O2. These findings shed light into the oxidant-dependent events that underlie cellular responses to environmental electrophiles.

Immunochemical method to detect proteins that undergo selective modification by 1,2-naphthoquinone derived from naphthalene through metabolic activation.

Naphthalene undergoes biotransformation by a variety of enzymes to yield 1,2-naphthoquinone (1,2-NQ), a reactive metabolite that binds covalently to proteins. Because this covalent modification is thought to account for naphthalene toxicity, a procedure to detect 1,2-NQ bound to macromolecules is required. In this study, we prepared a polyclonal antibody against 1,2-NQ and examined the specificities of the antibody for various aromatic structures and for the regiochemistry of the quinone functionality. Western blot analysis revealed that the antibody prepared against 1,2-NQ recognized the naphthalene moiety with the ortho-dicarbonyl group, but not with the para-dicarbonyl group; in addition, little cross-reactivity of ortho-quinones with different numbers of aromatic rings (n = 1, 3, 4, 5, 6) was seen. Dot blot and Western blot analyses with the polyclonal antibody enabled quantitative determination of the formation of protein-bound 1,2-NQ during the metabolic activation of naphthalene. The present method can be expected to applicable for the identification of the molecular targets of 1,2-NQ derived from naphthalene in cells and tissues.

Expression, purification, and characterization of anti-plumbagin single-chain variable fragment antibody in Sf9 insect cell.

Plumbagin (PL; 5-hydroxy-2-methyl-1, 4-naphthoquinone) is an important secondary metabolite, mainly produced in the Plumbago zeylanica L. (Plumbaginaceae). A single-chain variable fragment (scFv) antibody, fusion of the variable regions of the heavy chain and light chain of immunoglobulin against PL (PL-scFv) was expressed by Bac-to-Bac Baculovirus Expression System using Spodoptera frugiperda (Sf9) insect cells and characterized to investigate potential use of PL-scFv as a tool for plant immunomodulation. Functional PL-scFv expressed in the Sf9 insect cells were purified using cation exchange chromatography followed by immobilized metal ion affinity chromatography (IMAC). The yields of the purified PL-scFv in the culture supernatant and Sf9 insect cells were 2.0 mg and 5.2 mg per 1 liter of Sf9 culture medium, respectively. Recombinant purified PL-scFv was then characterized by the indirect competitive enzyme-linked immunosorbent assay (ELISA). The cross-reactivity and sensitivity of PL-scFv expressed in Sf9 insect cells were compared with PL-scFv expressed in Escherichia coli and its parental anti-plumbagin monoclonal antibody (MAb 3A3) secreted from hybridoma cells. Intriguingly, the specificity of the PL-scFv expressed in Sf9 insect cells was found to be different from that expressed in E. coli and parental MAb 3A3, although the detectable level (0.2-25 µg/mL) was the same in ELISA using each antibody. Even more interestingly, the characteristics of PL-scFv, which have wide cross-reactivity against 1,4-napththoquinone, suggest its potential use as a tool for plant immunomodulation not only for breeding Plumbaginacea family containing PL but also for breeding other medicinal plants containing bioactive naphthoquinones.

Allergic reactions to henna-based temporary tattoos and their components.

Temporary henna-based tattoos, particularly popular among western tourists holidaying in exotic places, can expose to the risk to develop allergic reactions. Although hypersensitivity to henna is extremely rare, para-phenylenediamine, which is sometimes added to henna to obtain a dark, blackish color, is a frequent contact sensitizer. The purpose of this article is to review the literature about allergic reactions to temporary henna tattoos and outline the causes, clinical aspects and complications of this practice that should not be regarded as innocuous and risk-free.

Development of sensitivity-improved fluorescence-linked immunosorbent assay using a fluorescent single-domain antibody against the bioactive naphthoquinone, plumbagin.

A fluorescent single-domain antibody (fluobody), a fusion protein of a green fluorescent protein extracted from Aequorea coerulescens (AcGFP), a mutant that has been codon-optimized for mammalian expression, and a single-chain variable fragment antibody (scFv), against plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone; PL) was successfully constructed and expressed in Escherichia coli. The expressed fluobody was purified, refolded, and characterized to develop a speedy, simple, and sensitive fluorescence-linked immunosorbent assay (FLISA) for the determination of PL. In this study, two kinds of fluobody containing PL-scFv at the N-terminus of AcGFP (N fluobody) or the C-terminus of AcGFP (C fluobody) were constructed with flexible amino acid linker (Gly(4)Ser)(2) between PL-scFv and AcGFP for comparative purposes. Characterization of the fluobodies revealed that the C fluobody has better properties as a probe for FLISA than the N fluobody because the fluorescence intensity of C fluobody was 18-fold higher than that of N fluobody. Moreover, C fluobody exhibited a fourfold-higher binding affinity than the N fluobody. More interestingly, the limit of detection for PL measurement in FLISA (24 ng mL(-1)) was improved to eightfold higher than that in conventional ELISA (0.2 microg mL(-1)), indicating that a sensitive immunoassay could be developed by using fluobody instead of monoclonal antibody or scFv.

Construction and expression of specificity-improved single-chain variable fragments against the bioactive naphthoquinone, plumbagin.

We constructed a single-chain variable fragment (scFv) antibody against plumbagin (PL) with improved specific binding to PL. Variable heavy- and light-chain genes were cloned directly from the cDNA of hybridoma cell line 3A3 and assembled using the splice-overlap extension polymerase chain reaction (SOE-PCR) with specific primers including flexible peptide (Gly(4)Ser)(3) linker primers. The constructed scFv gene was ligated into the pET28a expression vector and transformed into Escherichia coli BL21 (DE3). The denatured protein expressed as inclusion bodies in E. coli was solubilized, purified, and refolded by a stepwise dialysis. Intriguingly, the refolded scFv against PL displayed higher PL-binding specificity than that of its parental monoclonal antibody, MAb 3A3, which suggests the possibility of improving the function by constructing the scFv antibody. These notable properties of the recombinant antibody against PL made it possible to develop an enzyme-linked immunosorbent assay (ELISA) for reliable determination of PL.

Allergic contact dermatitis from temporary henna tattoo.

Temporary henna tattooing has been very popular during recent years. Henna (Lawsonia inermis) is a plant from the Lythraceae family. For henna tattooing, henna dye is used. It is a dark green powder, made from the leaves of the plant, used for hair dyeing and body tattooing. Very often, para-phenylenediamine (PPD) is added to henna dye to make color blacker and to speed up dyeing. PPD may be a very potent contact sensitizer. We report a 9-year-old boy with allergic contact dermatitis due to temporary henna tattooing. Patch testing showed a positive reaction to PPD. After the treatment with topical corticosteroid and oral antihistamines, the lesion cleared with discrete residual hypopigmentation.

Development of an enzyme-linked immunosorbent assay (ELISA) using highly-specific monoclonal antibodies against plumbagin.

Plumbagin (PL; 5-hydroxy-2-methyl-1,4-naphthoquinone) is a natural compound mainly isolated from Plumbago zeylanica. This plant is distributed in Southeast Asia, and well known as Ayurvedic medicine in India for its medicinal properties. PL has been shown to have various pharmacological activities. We have successfully prepared monoclonal antibodies against PL, and developed an enzyme-linked immunosorbent assay (ELISA) system for determination of PL. 3-(5-Hydroxy-2-methyl-1,4-naphthoquinone-3-yl) propanoic acid was synthesized and purified to prepare PL-bovine serum albumin conjugate (PL-BSA), which was used as an immunogen. PL-BSA conjugate was administered into BALB/c male mice for production of monoclonal antibodies against PL. The monoclonal antibody against PL which is secreted from established hybridoma cell line 3A3 (MAb 3A3) has been proven to have highly-specific to PL resulting from cross-reactivities test. The range for calibration of PL by ELISA was 0.2-25 microg mL(-1). Based on validation analysis, this analytical method by ELISA is a precise, accurate, and sensitive method for the determination of PL in plant.

[Chemical biology of 1,2-naphthoquinone, a novel air pollutant that affects signal transduction pathways].

Prolonged exposure of humans to ambient particulate matter such as diesel exhaust particles (DEP) induces a variety of adverse health effects including cardiovascular diseases, asthma and cancer. Polycyclic aromatic hydrocarbons (PAHs) and their derivatives in DEP are thought to be potential candidates for the deleterious effects of DEP. We have identified 1,2-naphthoquinone (1,2-NQ) as a novel PAH quinone that contaminates DEP. Because 1,2-NQ is covalently bound to macromolecules through reactive thiols (thiolate ions), our rationale was that cellular proteins modified by 1,2-NQ seem to act as a redox-sensor and thus the interaction of thiol proteins with 1,2-NQ may disrupt their functions. To address our hypothesis, we prepared specific antibody against 1,2-NQ bound to proteins. In this review, we introduce an inhibitor of kappaB kinasebeta (IKKbeta) and protein tyrosine phosphatase 1B (PTP1B) as target molecules for 1,2-NQ. Although IKKbeta activates transcription factor NF-kappaB and PTP1B negatively regulates the receptor-protein tyrosine kinase, such as epidermal growth factor receptor (EGFR) in cells, covalent modification of these proteins caused by 1,2-NQ results in inhibition of NF-kappaB activity and transactivation of EGFR.