Enhanced glycolytic metabolism supports transmigration of brain-infiltrating macrophages in multiple sclerosis
Deepak Kumar Kaushik, … , Jong M. Rho, V. Wee Yong
Deepak Kumar Kaushik, … , Jong M. Rho, V. Wee Yong
Published May 21, 2019
Citation Information: J Clin Invest. 2019;129(8):3277-3292. https://doi.org/10.1172/JCI124012.
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Research Article Autoimmunity Metabolism

Enhanced glycolytic metabolism supports transmigration of brain-infiltrating macrophages in multiple sclerosis

Abstract

The migration of leukocytes into the CNS drives the neuropathology of multiple sclerosis (MS). It is likely that this penetration utilizes energy resources that remain to be defined. Using the experimental autoimmune encephalomyelitis (EAE) model of MS, we determined that macrophages within the perivascular cuff of postcapillary venules are highly glycolytic, as manifested by strong expression of lactate dehydrogenase A (LDHA), which converts pyruvate to lactate. These macrophages expressed prominent levels of monocarboxylate transporter-4 (MCT-4), which is specialized in the secretion of lactate from glycolytic cells. The functional relevance of glycolysis was confirmed by siRNA-mediated knockdown of LDHA and MCT-4, which decreased lactate secretion and macrophage transmigration. MCT-4 was in turn regulated by EMMPRIN (also known as CD147), as determined through coexpression and co-IP studies and siRNA-mediated EMMPRIN silencing. The functional relevance of MCT-4–EMMPRIN interaction was confirmed by lower macrophage transmigration in culture using the MCT-4 inhibitor α-cyano-4-hydroxy-cinnamic acid (CHCA), a cinnamon derivative. CHCA also reduced leukocyte infiltration and the clinical severity of EAE. Relevance to MS was corroborated by the strong expression of MCT-4, EMMPRIN, and LDHA in perivascular macrophages in MS brains. These results detail the metabolism of macrophages for transmigration from perivascular cuffs into the CNS parenchyma and identify CHCA and diet as potential modulators of neuroinflammation in MS.

Authors

Deepak Kumar Kaushik, Anindita Bhattacharya, Reza Mirzaei, Khalil S. Rawji, Younghee Ahn, Jong M. Rho, V. Wee Yong

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Figure 1

Perivascular cuffs in EAE cerebellum and cervical spinal cord harbor LDHA-expressing leukocytes.

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Perivascular cuffs in EAE cerebellum and cervical spinal cord harbor LDH...
(A) Low-magnification image shows a lateral section of an EAE mouse cerebellum (arrows point to perivascular cuffs) along with enlarged images of a perivascular cuff labeled with pan-laminin (green) and the pan-leukocyte marker CD45 (red). Scale bars: 50 μm. (B) Expression of LDHA and CD45 in a low-magnification cerebellar section of EAE depicts detectable LDHA expression exclusively in CD45+ cells within the white matter. Scale bar: 100 μm. (C) Representative images of individual cuffs (demarcated by a dotted line) at higher magnification (scale bars: 50 μm) show the expression of LDHA in CD45+ cells in D16 EAE cerebella and spinal cords. Images are representative of 8 mice from 3 independent experiments. 3D reconstruction using Imaris confirmed the presence of LDHA within the CD45+ cells in the inflammatory cuffs (scale bars: 20 μm). (D) Representative images show LDHA expression within F4/80+ macrophages; images are representative of 8 mice from 3 independent experiments (scale bar: 50 μm), with a corresponding 3D reconstruction of this image (scale bar: 20 μm). Insets in C and D show magnified cells (original magnification of insets, ×120). (E) Percentage of LDHA+CD45+ cells within the perivascular cuffs of D16 EAE mice (peak EAE; n = 3 mice; 2 sections per mouse were analyzed). (F) Lactate levels measured in spinal cord homogenates from 3 D16 EAE mice and 3 naive mice using the L-lactate assay kit. Graphs show the mean ± SD. Data were compared using a 2-tailed Student’s t test. *P < 0.05.