Irinotecan and its metabolite SN38 inhibits procollagen I production of dermal fibroblasts from Systemic Sclerosis patients

Systemic sclerosis (SSc) is a rare autoimmune connective tissue disease characterized by a microangiopathy and fibrosis of the skin and internal organs. No treatment has been proved to be efficient in case of early or advanced SSc to prevent or reduce fibrosis. There are strong arguments for a key role of topo-I in the pathogenesis of diffuse SSc. Irinotecan, a semisynthetic derivative of Camptothecin, specifically target topo-I. This study was undertaken to evaluate the effects of noncytotoxic doses of irinotecan or its active metabolite SN38 on collagen production in SSc fibroblasts. Dermal fibroblasts from 4 patients with SSc and 2 healthy donors were cultured in the presence or absence of irinotecan or SN38. Procollagen I release was determined by ELISA and expression of a panel of genes involved in fibrosis was evaluated by qRT-PCR. Subcytotoxic doses of irinotecan and SN38 caused a significant and dose-dependent decrease of the procollagen I production in dermal fibroblasts from SSc patients, respectively − 48 ± 3%, p < 0.0001 and − 37 ± 6.2%, p = 0.0097. Both irinotecan and SN38 led to a global downregulation of genes involved in fibrosis such as COL1A1, COL1A2, MMP1 and ACTA2 in dermal fibroblasts from SSc patients (respectively − 27; − 20.5; − 30.2 and − 30% for irinotecan and − 61; − 55; − 50 and − 54% for SN38). SN38 increased significantly CCL2 mRNA level (+ 163%). The inhibitory effect of irinotecan and its active metabolite SN38 on collagen production by SSc fibroblasts, which occurs through regulating the levels of expression of genes mRNA, suggests that topoisomerase I inhibitors may be effective in limiting fibrosis in such patients.

Monoclonal Antibodies From Anti-NMDA Receptor Encephalitis Patient as a Tool to Study Autoimmune Seizures

Anti-N-methyl-D-aspartate (NMDA) receptor encephalitis manifests with precipitous cognitive decline, abnormal movements, and severe seizures that can be challenging to control with conventional anti-seizure medications. We previously demonstrated that intracerebroventricular (i.c.v.) administration of cerebrospinal fluid from affected patients, or purified NMDA receptor antibodies from encephalitis patients to mice precipitated seizures, thereby confirming that antibodies are directly pathogenic for seizures. Although different repertoires of anti-NMDA receptor antibodies could contribute to the distinct clinical manifestations in encephalitis patients, the role of specific antibodies in the expression of seizure, motor, and cognitive phenotypes remains unclear. Using three different patient-derived monoclonal antibodies with distinct epitopes within the N-terminal domain (NTD) of the NMDA receptor, we characterized the seizure burden, motor activity and anxiety-related behavior in mice. We found that continuous administration of 5F5, 2G6 or 3C11 antibodies for 2 weeks precipitated seizures, as measured with continuous EEG using cortical screw electrodes. The seizure burden was comparable in all three antibody-treated groups. The seizures were accompanied by increased hippocampal C-C chemokine ligand 2 (CCL2) mRNA expression 3 days after antibody infusion had stopped. Antibodies did not affect the motor performance or anxiety scores in mice. These findings suggest that neuronal antibodies targeting different epitopes within the NMDA receptor may result in a similar seizure phenotype.

ACE2 Is Expressed in Immune Cells That Infiltrate the Placenta in Infection-Associated Preterm Birth

COVID-19 is associated with increased incidence of preterm birth (PTB). We assessed pathways by which SARS-CoV-2 could access the placenta. Placentae, from PTB with or without chorioamnionitis (ChA), or from term pregnancies (n = 12/13/group) were collected. Peripheral blood was collected from healthy pregnant women (n = 6). Second trimester placental explants (16–20 weeks, n = 5/group) were treated with lipopolysaccharide (LPS, to mimic bacterial infection) and ACE2, CCL2, IL-6/8 and TNFα mRNA was assessed. ChA-placentae exhibited increased ACE2 and CCL2 mRNA expression (p < 0.05). LPS increased cytokine and ACE2 mRNA in placental explants. Placental ACE2 protein localized to syncytiotrophoblast, fetal endothelium, extravillous trophoblast and in immune cells-subsets (M1/M2 macrophage and neutrophils) within the villous stroma. Significantly increased numbers of M1 macrophage and neutrophils were present in the ChA-placenta (p < 0.001). Subsets of peripheral immune cells from pregnant women express the ACE2 mRNA and protein. A greater fraction of granulocytes was positive for ACE2 protein expression compared to lymphocytes or monocytes. These data suggest that in pregnancies complicated by ChA, ACE2 positive immune cells in the maternal circulation have the potential to traffic SARS-CoV-2 virus to the placenta and increase the risk of vertical transmission to the placenta/fetus.

Elevated circulating CCL2 in prostate cancer patients.

201 Background: Monocyte chemoattractant protein 1 (CCL2 or MCP-1), a chemokine secreted by monocytic cells, is critical in recruiting Treg and MDSCs into the tumor microenvironment and in regulating prostate cancer (PCa) migration and proliferation. In this study, we examined circulating CCL2 levels in healthy vs PCa patients and used an in vitro coculture model to identify the source of the elevated CCL2. Methods: Serum CCL2 concentrations were evaluated via ELISA in 59 patients (19 health controls, 20 “treatment naïve” PCa, 20 mCRPC). Monocytic leukemia cells (U937) were either directly cocultured with PC3 PCa cell line or cultured in the PC3 conditioned medium (CM). The induction of CCL2 mRNA in the cultures was examined by qPCR. The secretion of CCL2 into cell culture supernatants was evaluated via human cytokine array. Neutralizing antibodies to several overexpressed inflammatory cytokines in PC3 cells were added into the PC3 CM to evaluate the contribution of these inflammatory cytokines to CCL2 induction. Results: Circulating CCL2 concentrations were significantly higher in prostate cancer patient serum compared to control patient serum (p=4.4e-6) (Table). To understand the potential source of elevated CCL2, we grew U937 and PC3 in coculture and evaluated with qPCR, revealing that while CCL2 was not expressed in PC3 cells, it was expressed at very low levels in U937 cells. Interestingly, coculture of PC3 with U937 increased CCL2 mRNA expression by over 10-fold, and the result was confirmed at protein levels by human cytokine array. Our results also indicated that IL-6 and GM-SCF were the two major cytokines released by PCa cells to induce CCL2 mRNA in U937 cells and MEK and JAK-STAT signaling were crucial for CCL2 induction. Conclusions: Prostate cancer cells induce CCL2 secretion from monocytes in an IL-6 and GM-CSF dependent manner. Given the critical role of CCL2 in mediating immunosuppressive tumor microenvironments, our study highlighted the CCL2 Concentrations in PCa vs Healthy Serum.[Table: see text]

Exosomal CCL2 from Tubular Epithelial Cells Is Critical for Albumin-Induced Tubulointerstitial Inflammation

Albuminuria is a key instigator of tubulointerstitial inflammation associated with CKD, but the mechanism through which filtered albumin propagates renal injury remains unclear. In this study, we explored the role in this process of exosome mRNA released from tubular epithelial cells (TECs). Compared with control mice, acute and chronic kidney injury models had more exosomes containing inflammatory cytokine mRNA, particularly the chemokine CCL2, in kidneys and urine. In vitro stimulation of TECs with BSA recapitulated this finding. Notably, the internalization of purified TEC exosomes by cultured macrophages increased if TECs were exposed to BSA. Macrophage internalization of exosomes from BSA-treated TECs led to an enhanced inflammatory response and macrophage migration, but CCL2 silencing in TECs prevented these effects. Using a GFP-CCL2 fusion mRNA construct, we observed direct transfer of CCL2 mRNA from TEC exosomes to macrophages. Mice subjected to tail vein injection of purified BSA-treated TEC exosomes developed tubular injury with renal inflammatory cell infiltration. However, injection of exosomes from BSA-treated CCL2-deficient TECs induced less severe kidney inflammation. Finally, in patients with IgA nephropathy, the increase of proteinuria correlated with augmented urinary excretion of exosomes with exaggerated expression of CCL2 mRNA. Moreover, the level of CCL2 mRNA in urinary exosomes correlated closely with levels of renal interstitial macrophage infiltration in these patients. Our studies demonstrate that the increasing release of exosomes that transfer CCL2 mRNA from TECs to macrophages constitutes a critical mechanism of albumin-induced tubulointerstitial inflammation.

CCL2 is Upregulated by Decreased miR-122 Expression in Iron-Overload-Induced Hepatic Inflammation

Background/Aims: Iron overload (IO) is accompanied by hepatic inflammation. The chemokine (C-C motif) ligand 2 (CCL2) mediates inflammation, and its overexpression is associated with IO. However, whether IO results in CCL2 overexpression in the liver and the underlying mechanisms are unclear. Methods: We subjected mice to IO by administering intraperitoneal injections of dextran-iron or by feeding mice a 3% dextran-iron diet to observe the effects of IO on miR-122/CCL2 expression through real-time qPCR and Western blot analysis. We also used indicators, including the expression of the inflammatory cytokine, the inflammation score based on H&E staining and the serum content of ALT and AST to evaluate the effects of IO on hepatic inflammation. Meanwhile, we observed the effects of vitamin E on IO-induced hepatic inflammation. In cells, we used 100 µΜ FeSO4 or 30 µΜ Holo-Tf to produce IO and observed the roles of miR-122 in regulating CCL2 expression by using miR-122 mimics or inhibitors to overexpress or inhibit miR-122. Then, we used a dual-luciferase reporter assay to prove that miR-122 regulates CCL2 expression through direct binding to its complementary sequence in the CCL2 mRNA 3’UTR. Results: IO induces the downregulation of miR-122 and the upregulation of CCL2, as well as inflammatory responses both in vitro and in vivo. Although IO-induced oxidative stress is eliminated by the antioxidant vitamin E, IO-induced hepatic inflammation still exists, which probably can be explained by the fact that vitamin E has no effects on the miR-122/CCL2 pathway. In in vitro experiments, the overexpression and inhibition of miR-122 significantly reduced and increased CCL2 expression, respectively. The dual-luciferase reporter assay indicates that miR-122 binds CCL2 mRNA 3’UTR. Conclusion: We propose the roles of miR-122/CCL2 in IO-induced hepatic inflammation. Our studies should provide a new clue for developing clinical strategies for patients with IO.