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Background: Glyoxalase domain containing protein 4 (GLOD4), a protein of an unknown function, is associated with Alzheimer's disease (AD). Three GLOD4 isoforms are known. The mechanism underlying GLOD4's association with AD was unknown. Objective: To assess GLOD4's role in the central nervous system by studying GLOD4 isoforms expression in human frontal cerebral cortical tissues from AD patients and in brains of Blmh–/–5xFAD mouse AD model of AD. Methods: GLOD4 protein and mRNA were quantified in human and mouse brains by western blotting and RT-qPCR, respectively. Mouse brain amyloid-β (Aβ) was quantified by western blotting. Behavioral assessments of mice were performed by cognitive/neuromotor testing. Glod4 gene in mouse neuroblastoma N2a-APPswe cells was silenced by RNA interference and Glod4, Aβ precursor protein (Aβpp), Atg5, p62, and Lc3 proteins and mRNAs were quantified. Results: GLOD4 mRNA and protein isoforms were downregulated in cortical tissues from AD patients compared to non-AD controls. Glod4 mRNA was downregulated in brains of Blmh–/–5xFAD mice compared to Blmh+/+5xFAD sibling controls, but not in Blmh–/– mice without the 5xFAD transgene compared to Blmh+/+ sibling controls. The 5xFAD transgene downregulated Glod4 mRNA in Blmh–/– mice of both sexes and in Blmh+/+ males but not females. Attenuated Glod4 was associated with elevated Aβ and worsened memory/sensorimotor performance in Blmh–/–5xFAD mice. Glod4 depletion in N2a-APPswe cells upregulated AβPP, and downregulated autophagy-related Atg5, p62, and Lc3 genes. Conclusions: These findings suggest that GLOD4 interacts with AβPP and the autophagy pathway, and that disruption of these interactions leads to Aβ accumulation and cognitive/neurosensory deficits. [ABSTRACT FROM AUTHOR]

The inability to efficiently metabolize homocysteine (Hcy) due to nutritional and genetic deficiencies, leads to hyperhomocysteinemia (HHcy) and endothelial dysfunction, a hallmark of atherosclerosis which underpins cardiovascular disease (CVD). PHF8 is a histone demethylase that demethylates H4K20me1, which affects the mammalian target of rapamycin (mTOR) signaling and autophagy, processes that play important roles in CVD. PHF8 is regulated by microRNA (miR) such as miR‐22‐3p and miR‐1229‐3p. Biochemically, HHcy is characterized by elevated levels of Hcy, Hcy‐thiolactone and N‐Hcy‐protein. Here, we examined the effects of these metabolites on miR‐22‐3p, miR‐1229‐3p, and their target PHF8, as well as on the downstream consequences of these effects on H4K20me1, mTOR‐, and autophagy‐related proteins and mRNAs expression in human umbilical vein endothelial cells (HUVEC). We found that treatments with N‐Hcy‐protein, Hcy‐thiolactone, or Hcy upregulated miR‐22‐3p and miR‐1229‐3p, attenuated PHF8 expression, upregulated H4K20me1, mTOR, and phospho‐mTOR. Autophagy‐related proteins (BECN1, ATG5, ATG7, lipidated LC3‐II, and LC3‐II/LC3‐I ratio) were significantly downregulated by at least one of these metabolites. We also found similar changes in the expression of miR‐22‐3p, Phf8, mTOR‐ and autophagy‐related proteins/mRNAs in vivo in hearts of Cbs−/− mice, which show severe HHcy and endothelial dysfunction. Treatments with inhibitors of miR‐22‐3p or miR‐1229‐3p abrogated the effects of Hcy‐thiolactone, N‐Hcy‐protein, and Hcy on miR expression and on PHF8, H4K20me1, mTOR‐, and autophagy‐related proteins/mRNAs in HUVEC. Taken together, these findings show that Hcy metabolites upregulate miR‐22‐3p and miR‐1229‐3p expression, which then dysregulate the PHF8/H4K20me1/mTOR/autophagy pathway, important for vascular homeostasis. [ABSTRACT FROM AUTHOR]

Elevated levels of homocysteine (Hcy) and related metabolites are associated with Alzheimer's disease (AD). Severe hyperhomocysteinemia causes neurological deficits and worsens behavioral and biochemical traits associated with AD. Although Hcy is precluded from entering the Genetic Code by proofreading mechanisms of aminoacyl-tRNA synthetases, and thus is a non-protein amino acid, it can be attached to proteins via an N-homocysteinylation reaction mediated by Hcy-thiolactone. Because N-homocysteinylation is detrimental to a protein's function and biological integrity, Hcy-thiolactone-detoxifying enzymes—PON1, BLMH, BPHL—have evolved. This narrative review provides an account of the biological function of these enzymes and of the consequences of their impairments, leading to the phenotype characteristic of AD. Overall, accumulating evidence discussed in this review supports a hypothesis that Hcy-thiolactone contributes to neurodegeneration associated with a dysregulated Hcy metabolism. [ABSTRACT FROM AUTHOR]

Objectives—Metallic elements and fibrin clot properties have been linked to stroke. We examined metallic and nonmetallic elements, fibrin clot lysis time (CLT), and maximum absorbance (Absmax) in relation to ischemic stroke. Design—A case–control study of ischemic stroke patients vs. healthy individuals. Subjects and Methods—Plasma and serum were collected from 260 ischemic stroke patients (45.0% women; age, 68 ± 12 years) and 291 healthy controls (59.7% women; age, 50 ± 17 years). Fibrin CLT and Absmax were measured using a validated turbidimetric assay. Serum elements were quantified by inductively coupled plasma mass spectrometry (ICP-MS) and optical emission spectrometry (ICP-OES). Data were analyzed by bivariate correlations and multiple or logistic regression. Results—In female stroke patients, copper, lithium, and aluminum were significantly lower compared with controls; in male stroke patients, potassium was lower, and beryllium was elevated. In female and male stroke patients, iron, zinc, nickel, calcium, magnesium, sodium, and silicon were significantly lower, while strontium was elevated. Positive correlations between fibrin clot properties and metals, observed in healthy controls, were lost in ischemic stroke patients. In multivariate regression analysis, fibrin CLT and/or Absmax was associated with zinc, calcium, potassium, beryllium, and silicon in stroke patients and with sodium, potassium, beryllium, and aluminum in controls. In logistic regression analysis, stroke was independently associated with lithium, nickel, beryllium, strontium, boron, and silicon and with sodium, potassium, calcium, and aluminum but not with fibrin CLT/Absmax. Conclusions—Various elements were associated with fibrin clot properties and the risk of ischemic stroke. Lithium, sodium, calcium, and aluminum abrogated the association of fibrin clot properties with ischemic stroke. [ABSTRACT FROM AUTHOR]