The Trace Element Selenium Is Important for Redox Signaling in Phorbol Ester-Differentiated THP-1 Macrophages

Physiological selenium (Se) levels counteract excessive inflammation, with selenoproteins shaping the immunoregulatory cytokine and lipid mediator profile. How exactly differentiation of monocytes into macrophages influences the expression of the selenoproteome in concert with the Se supply remains obscure. THP-1 monocytes were differentiated with phorbol 12-myristate 13-acetate (PMA) into macrophages and (i) the expression of selenoproteins, (ii) differentiation markers, (iii) the activity of NF-κB and NRF2, as well as (iv) lipid mediator profiles were analyzed. Se and differentiation affected the expression of selenoproteins in a heterogeneous manner. GPX4 expression was substantially decreased during differentiation, whereas GPX1 was not affected. Moreover, Se increased the expression of selenoproteins H and F, which was further enhanced by differentiation for selenoprotein F and diminished for selenoprotein H. Notably, LPS-induced expression of NF-κB target genes was facilitated by Se, as was the release of COX- and LOX-derived lipid mediators and substrates required for lipid mediator biosynthesis. This included TXB2, TXB3, 15-HETE, and 12-HEPE, as well as arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Our results indicate that Se enables macrophages to accurately adjust redox-dependent signaling and thereby modulate downstream lipid mediator profiles.

Pengaruh Pemberian Ekstrak Biji Tanaman Jarak Pagar (Jatropha Curcas. L) Terhadap Gambaran Histopatologi Hepar dan Kadar SGPT (Serum Glutamic Piruvic Transaminase) pada Tikus (Rattus norvergicus)

Jarak Pagar atau Jatropha curcas L merupakan tanaman famili Eurphobiaceae dengan kegunaan secara medis dan non medis, diantaranya yaitu sebagai kontrasepsi oral. Bagian Jarak Pagar yang sering dimanfaatkan adalah bagian biji. Namun, Jarak Pagar juga mengandung saponin, phorbol ester, kursin, tanin yang dapat menyebabkan keracunan organ. Penelitian ini dilakukan untuk mengetahui pengaruh ekstrak biji Jarak Pagar terhadap histopatologi hati dan kadar SGPT tikus Rattus Norvegicus, dengan menggunakan metode Rancangan Acak Lengkap. Hewan coba dibagi dalam 4 kelompok, setiap kelompok terdiri dari 5 ekor tikus betina. Kelompok tersebut yaitu kelompok kontrol tanpa perlakuan dan kelompok perlakuan per oral ekstrak biji Jarak Pagar pada dosis 10, 50, dan 100 mg/kg BB. Proses induksi dilakukan setiap hari selama 14 hari, pada hari ke-15 dilakukan nekropsi. Organ hati diambil untuk analisis histologi dan sampel darah diambil untuk mengukur kadar SGPT. Hasil penelitian menunjukkan bahwa pemberian ekstrak biji Jarak Pagar dapat meningkatkan kadar SGPT. Pemberian ekstrak biji Jarak Pagar pada dosis 100 mg/kg berat badan menginduksi kerusakan hepatosit paling parah di antara kelompok perlakuan.

Lophira alata Suppresses Phorbol Ester-Mediated Increase in Cell Growth via Inhibition of Protein Kinase C-α/Akt in Glioblastoma Cells

Background: Medicinal plants serve as sources of compounds used to treat other types of cancers. The root of the plant Lophira alata (Ochnaceae) has been used as a component of traditional herbal decoctions administered to cancer patients in southwestern Nigeria. However, the mechanism of the cytotoxic effects of Lophira alata alone or in the presence of phorbol ester has not been investigated in brain tumor cells. Objective: This study was aimed at examining the cytotoxic potential of the methanolic fraction of Lophira alata root on malignant glioma invasive cellular growth and survival. Method: The methanolic fraction of Lophira alata (LAM) was subjected to high-performance liquid chromatography to determine the fingerprints of the active molecules. The antiproliferative effects of Lophira alata were assessed using the MTT and LDH assays. Protein immunoblots were carried out to test the effects of Lophira alata, alone or in the presence of phorbol ester, on survival signaling pathways such as Akt, mTOR, and apoptotic markers such as PARP and caspases. Results: The methanolic fraction of Lophira alata (LAM) induced a concentration-dependent and time-dependent decrease in glioma cell proliferation. In addition, LAM attenuated phorbol ester-mediated signaling of downstream targets such as Akt/mTOR. Gene silencing using siRNA targeting PKC-alpha attenuated LAM-mediated downregulation of Akt. In addition, LAM induced both PARP and caspase cleavages. The HPLC fingerprint of the fraction indicates the presence of flavonoids. Conclusion: LAM decreases cell proliferation and induces apoptosis in glioma cell lines and thus could serve as a therapeutic molecule in the management of gliomas.

Degradation of Phorbol Esters on the Jatropha curcas Linn. Seed by Biological Detoxification

The application of fermentation is one of methods to increase food quality biologically. Availability of Jatropha curcas residual from oil factory be focused as a soybean meal or fish meal replacement. On the other hand, J. curcas residuals possess a toxic compound as well. This study aimed to examine the effect of Aspergillus niger on the nutrition and harmful content of J. curcas as a potential ingredient of feed. In brief, J. curcas residual was fermented with a detoxification method at 3 d, 5 d, and 7 d. Crude protein, fat, and crude fiber content were assessed to discover the biological responses of J. curcas post–fermentation while phorbol ester was evaluated to toxic content post–detoxification. The results showed that crude protein and fat content were highest on 7 d post–fermentation but it was no significant difference (p > 0.05). While crude fiber content showed significant difference which the 3 d fermentation had the highest content of fiber. For phorbol ester content, 3 d fermentation showed a better result than the control group (p < 0.05). The present findings suggest that A. niger is recommendable as starter to reduce fiber and toxic content of J. curcas residual at 3 d fermentation.

Mechanisms of protein kinase C epsilon down-regulation by transforming growth factor-beta in lung cancer cells

ABSTRACTProtein kinase C epsilon (PKCε), a diacylglycerol (DAG)/phorbol ester-regulated PKC isoform, has been widely linked to oncogenesis and metastasis. PKCε plays important roles in the regulation of motility and invasiveness in non-small cell lung cancer (NSCLC). We previously reported that this kinase becomes prominently down-regulated upon TGF-β-induced epithelial-to-mesenchymal transition (EMT), which leads to prominent phenotypic changes. While the phorbol ester PMA causes down-regulation of PKCα, δ and ε within hours, TGF-β requires at least 4 days to reduce the expression levels of PKCε without affecting the expression of other PKCs, an effect that parallels the acquisition of a mesenchymal phenotype. Despite the prominent transcriptional component involved in EMT, we found that PKCε down-regulation does not involve changes in PKCε mRNA levels and was entirely independent of transcriptional activation of the PRKCE gene. Further mechanistic analysis revealed that the reduction in PKCε expression is dependent on proteasomal and endolysosomal pathways, but independent of autophagy processing mechanisms. Site-directed mutagenesis of Lys312 and Lys321 in PKCε prevented its down-regulation in response to either TGF-β or the phorbol ester PMA. The shift in PKCε isozyme levels depending on cell plasticity underscores relevant functional consequences by modulating the expression of this oncogenic/metastatic kinase and highlights key roles of protein stability mechanisms in the control of PKCε phenotypic outcomes.