Monocytes and Monocyte-Derived Antigen-Presenting Cells Have Distinct Gene Signatures in Experimental Model of Multiple Sclerosis

Abstract

Multiple sclerosis (MS) is a chronic inflammatory disease mediated by a complex interaction between the autoreactive lymphocytes and the effector myeloid cells within the central nervous system (CNS). In a murine model of MS, experimental autoimmune encephalomyelitis (EAE), Ly6Chi monocytes migrate into the CNS and further differentiate into antigen-presenting cells (APCs) during disease progression. Currently, there is no information about gene signatures that can distinguish between monocytes and the monocyte-derived APCs. We developed a surface marker-based strategy to distinguish between these two cell types during the stage of EAE when the clinical symptoms were most severe, and performed transcriptome analysis to compare their gene expression. We report here that the inflammatory CNS environment substantially alters gene expression of monocytes, compared to the monocyte differentiation process within CNS. Monocytes in the CNS express genes that encode proinflammatory cytokines and chemokines, and their expression is mostly maintained when the cells differentiate. Moreover, monocyte-derived APCs express surface markers associated with both dendritic cells and macrophages, and have a significant up-regulation of genes that are critical for antigen presentation. Furthermore, we found that Ccl17, Ccl22, and Ccr7 are expressed in monocyte-derived APCs but not the Ly6Chi monocytes. These findings may shed light on identifying molecular signals that control monocyte differentiation and functions during EAE.

Longitudinal omics in Syrian hamsters integrated with human data unravel complexity of moderate immune responses to SARS-CoV-2

“…We then used the predicted cell type of the majority of cells in each cluster to guide cluster annotation, also taking into account cell marker genes published in literature and cell marker databases (Franzen et al, 2019;Zhang et al, 2019). The following populations were confirmed: Alveolar macrophages (Siglecf + , Marco + ) (Han et al, 2018), interstitial macrophages (C1qb + ) (Angelidis et al, 2019), monocytic macrophages (Ccr2 + , Ccr5 + , Arg1 + ) (Lechner et al, 2017;Shaheen et al, 2019), Treml4 + -monocytes (Treml4 + ) (Briseno et al, 2016), neutrophils (S100a8 + , Cxcr2 + , Camp + ) (Schulte-Schrepping et al, 2020;Zhao et al, 2019), myeloid dendritic cells (mDC) (Flt3 + , H2-Ab1 hi , Irf8 lo , Tcf4 lo ) and plasmacytoid dendritic cells (pDC) (Flt3 + , H2-Ab1 hi , Irf8 hi , Tcf4 hi ) (Dutertre et al, 2019;Monaghan et al, 2019;Rodrigues et al, 2018; Tabula Muris Consortium, 2018), T / NK / cells (Cd3e + , Cd4 + or Cd8a + , Gzma + , Nkg7 + ) (Raredon et al, 2019;Smith et al, 2020;Tabula Muris Consortium, 2018;Zhao et al, 2019;Zhu et al, 2009), B cells (Cd79b + , Ms4a1 + ) (Cohen et al, 2018;Schulte-Schrepping et al, 2020), alveolar epithelial cells type 1 (Rtkn2 + ) (Angelidis et al, 2019), endothelial cells (Pecam1 + ) (Han et al, 2018), ciliated epithelial cells (Foxj1 + )…”

“…It is made available under a preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in The copyright holder for this this version posted December 19, 2020. ; https://doi.org/10.1101/2020.12.18.423524 doi: bioRxiv preprint by the expression of mitochondrial genes, were removed and the data was reintegrated using the workflow described above. Cell type annotations were assigned to the identified cluster using the follow marker genes: Classical (inflammatory) monocytes (Ccr2 + , Cx3cr1 lo , Adgre1 + ); non-classical (residential) monocytes (Ccr2 -, Cx3cr1 hi , Adgre1 + ) (Burgess et al, 2019;Cochain et al, 2018;Ronning et al, 2019); mature neutrophils (Cxcr2 + , S100a8 + , Camp lo , Retn lo , Ltf lo ) and immature neutrophils (Cxcr2 + , S100a8 + , Camp hi , Retn hi , Ltf hi ) (Kim et al, 2017;Schulte-Schrepping et al, 2020;Xie et al, 2020;Zhao et al, 2019); myeloid dendritic cells (Flt3 + , H2-Ab1 hi , Irf8 lo , Tcf4 lo ) and plasmacytoid dendritic cells (Flt3 + , H2-Ab1 hi , Irf8 hi , Tcf4 hi ) (Dutertre et al, 2019;Monaghan et al, 2019;Rodrigues et al, 2018;Tabula Muris Consortium, 2018); T cells (Cd3e + , Cd4 + or Cd8a + ) and activated T cells (Cd3e + , Cd4 + and/or Cd8a + , Gzma + ) (Raredon et al, 2019;Tabula Muris Consortium, 2018;Zhao et al, 2019;Zhu et al, 2009), natural killer (NK) cells (Cd3e -, Nkg7 + ) (Smith et al, 2020;Zhao et al, 2019); B cells (Cd79a + , Ms4a1 + ) (Cohen et al, 2018;Schulte-Schrepping et al, 2020;Zuccolo et al, 2013) and platelets (Gng11 + , Ppbp + ) (El-Gedaily et al, 2004;Schoggins, 2019). While cluster 17 showed no expression of Ccr2, the levels of Adgre1 and Cd14 were considerable and it was considered as comprising classical monocytes for the purposes of this study (Sampath et al, 2018).…”

Microglial Nox2 Plays a Key Role in the Pathogenesis of Experimental Autoimmune Encephalomyelitis

“…In addition to the aforementioned changes in secreted cytokines and chemokines ( Figure 7B ), expression of chemotactic gene Pf4 ( 33 ) and proinflammatory cytokines and chemokines Tnfrsf9 , Tnfsf12 , Tnfsf13 , Ccl7 , Cxcl3 , and Cxcl9 ( 34 – 39 ) also showed a reduction in response to Nox2 deficiency ( Figure 7C ). These results indicate that Nox2 plays a broad role in regulating the activation of microglia ( 1 , 40 ). Gene ontology analysis performed on the KEGG pathways ( Supplementary Table 3 ) revealed DEG enrichment in six pathways that are associated with virus infection (human papillomavirus infection, herpes simplex virus 1 infection, and human T-cell leukemia virus 1 infection), which are known to be associated with EAE-related signaling pathways, such as the MAPK and PI3K-Akt signaling pathways as well as cytokine-cytokine receptor interaction ( Figure 7D ).…”

“…Many drugs are available for MS therapy, but these treatments often do not effectively halt disease progression. Thus, the identification of disease-modifying drugs that can stop MS progression are urgently needed ( 1 ). Mouse experimental autoimmune encephalomyelitis (EAE) is widely used to model human MS ( 2 ).…”

Human Endogenous Retrovirus as Therapeutic Targets in Neurologic Disease

“…Under physiological conditions, microglia protect the brain by sensing pathogens, phagocytosing cell debris and promoting remyelination. However, under MS pathological conditions, microglia become activated and secrete proinflammatory molecules that directly damage myelin sheaths and oligodendrocytes, causing inflammation and neurodegeneration [135,136] (Figure 2, number 1). This proinflammatory environment attracts peripheral monocyte-derived macrophages and dendritic cells (DC), as well as peripheral autoreactive T lymphocytes, which enter the CNS through the BBB localized in CNS micro vessels [133,[137][138][139] (Figure 2, number 2).…”