Fig. 2

HM cycle metabolite levels and differentially expressed genes (DEG) identified in MG from HHcy Cbs-/- mice. A HM metabolic cycle. The production of universal methyl group donor SAM, methyltransferase inhibitor SAH and other major metabolites are indicated. B HM cycle metabolite in Cbs-/- mice. Metabolite levels in the HM cycle were evaluated in plasma and cortex from Cbs-/- and control mice using LC–ESI–MS/MS. Elevated levels of Hcy and SAH, as well as a reduced SAM/SAH ratio, were observed in the plasma and cortex of Cbs-/- mice. C Cerebrum RNA-seq and MG DEG identification. RNA sequencing was performed on MG isolated from the cerebrum of Cbs-/- and control mice using anti-CD11b Microbeads. DEGs in Cbs-/- MG were identified with a fold change > 1.5 and a p-value < 0.05. D Top neuro-immunological relevant canonical pathways. Pathways were identified using Ingenuity Pathway Analysis (IPA) based on 353 Cbs-/- MG DEG. The p-value and z-score are represented by red and blue bars, respectively. Positive z-scores indicate activation, whereas negative scores indicate inhibition of a pathway. E Cbs-/- MG DEGs in the top canonical pathways. DEGs involved in each of the top 10 canonical pathways in Cbs-/- MG are labeled in the volcano plots. MG migration and phagocytosis function related pathways are bolded. Ade, adenosine; Cbs, cystathionine beta synthase; DEG, differentially expressed gene; GPCR, G protein couple receptor; HHcy, hyperhomocysteinemia; IPA, ingenuity pathway analysis; LC–ESI–MS/MS, Liquid chromatography-electrospray ionization tandem mass spectrometry; Met, methionine; MG, microglia; PCP, planar cell polarity; SAH, s-adenosyl-L-homocysteine; SAM, s-adenosylmethionine