Department of Microbiology, All-India Institute of Medical Sciences (A.I.I.M.S.), Patna, Bihar, India.
Department of Molecular Parasitology, Rajendra Memorial Research Institute of Medical Sciences, Indian Council of Medical Research (I.C.M.R.), Patna, Bihar, India.
Int Immunopharmacol. 2017 Sep;50:130-138. doi: 10.1016/j.intimp.2017.06.010. Epub 2017 Jul 12.
Indian Post kala-azar dermal leishmaniasis (PKDL) is the cutaneous aftermath of visceral leishmaniasis (VL) caused by L. donovani. Vitamin D-regulated cationic antimicrobial peptide cathelicidin (hCAP-18/LL-37) has microbicidal and immunomodulatory role against cutaneous infections, but its role in PKDL remains elusive.
Skin snips and blood-derived monocytes of PKDL patients (n=46), before (BT) and after (AT) chemotherapy, were used for this study. Serum vitamin D3 level was evaluated by ELISA. Cathelicidin and vitamin D receptor (VDR) levels were analyzed by real-time PCR and flowcytometry in PKDL patients. The mechanistic effect of cathelicidin on macrophage differentiation and anti-leishmanial activity was assessed through RNA interference techniques followed by subsequent microscopic evaluation of in vitro parasite killing and Th1/Th2 counter-regulation by ELISA/RT-PCR.
Low vitamin D3 levels were accompanied with decreased expression of cathelicidin and VDR in PKDL-BT patients. Results suggested positive induction of VDR-dependent cathelicidin in PKDL macrophages by Amphotericin B treatment, which could be due to indirect effect of drug-induced IL12 upregulation. 1,25-Vitamin D3 stimulation induced cathelicidin in PKDL-BT patients through involvement of TLR2/IL-1β, but not TLR4. Cathelicidin also augmented the anti-leishmanial effect and macrophage activating potential of Amphotericin B, attributable to regulation of VDR-dependent enhancement of CD40, p-STAT-I and MHC-II expression leading to regulation of IL10/IL12 balance in PKDL-BT patient macrophages.
This study indicates that cathelicidin augments anti-leishmanial macrophage activating property of Amphotericin B in a TLR2/VDR dependent mechanism, and advocate the development of novel adjunct treatment modality of cathelicidin with conventional Amphotericin B in PKDL patients.
印度内脏利什曼病（VL）后皮肤利什曼病（PKDL）是由利什曼原虫引起的内脏利什曼病的皮肤后遗症。维生素 D 调节阳离子抗菌肽 cathelicidin（hCAP-18/LL-37）对皮肤感染具有杀菌和免疫调节作用，但它在 PKDL 中的作用仍不清楚。
本研究使用了 PKDL 患者（n=46）的皮肤活检和血液来源的单核细胞，分别在化疗前（BT）和化疗后（AT）。通过 ELISA 评估血清维生素 D3 水平。通过实时 PCR 和流式细胞术分析 PKDL 患者的 cathelicidin 和维生素 D 受体（VDR）水平。通过 RNA 干扰技术评估 cathelicidin 对巨噬细胞分化和抗利什曼原虫活性的机制作用，随后通过体外寄生虫杀伤的显微镜评估和 ELISA/RT-PCR 评估 Th1/Th2 反向调节。
低维生素 D3 水平伴随着 PKDL-BT 患者 cathelicidin 和 VDR 的表达降低。结果表明，两性霉素 B 治疗可诱导 PKDL 巨噬细胞中 VDR 依赖性 cathelicidin 的阳性诱导，这可能是由于药物诱导的 IL12 上调的间接作用。1,25-维生素 D3 刺激通过 TLR2/IL-1β参与诱导 PKDL-BT 患者的 cathelicidin，但不涉及 TLR4。Cathelicidin 还增强了两性霉素 B 的抗利什曼原虫作用和巨噬细胞激活潜力，归因于调节 VDR 依赖性增强 CD40、p-STAT-I 和 MHC-II 表达，从而调节 PKDL-BT 患者巨噬细胞中 IL10/IL12 平衡。
本研究表明，cathelicidin 通过 TLR2/VDR 依赖性机制增强了两性霉素 B 抗利什曼原虫的激活巨噬细胞特性，并主张在 PKDL 患者中开发 cathelicidin 与常规两性霉素 B 的新型辅助治疗方式。
