Filters
Association of GLOD4 with Alzheimer’s Disease in Humans and Mice
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.
Diet-induced hyperhomocysteinemia causes sex-dependent deficiencies in offspring musculature and brain function
Hyperhomocysteinemia (HHcy), characterized by elevated homocysteine (Hcy) levels, is a known risk factor for cardiovascular, renal, and neurological diseases, as well as pregnancy complications. Our study aimed to investigate whether HHcy induced by a high-methionine (high-Met) diet exacerbates cognitive and behavioral deficits in offspring and leads to other breeding problems. Dietary HHcy was induced four weeks before mating and continued throughout gestation and post-delivery. A battery of behavioral tests was conducted on offspring between postnatal days (PNDs) 5 and 30 to assess motor function/activity and cognition. The results were correlated with brain morphometric measurements and quantitative analysis of mammalian target of rapamycin (mTOR)/autophagy markers. The high-Met diet significantly increased parental and offspring urinary tHcy levels and influenced offspring behavior in a sex-dependent manner. Female offspring exhibited impaired cognition, potentially related to morphometric changes observed exclusively in HHcy females. Male HHcy pups demonstrated muscle weakness, evidenced by slower surface righting, reduced hind limb suspension (HLS) hanging time, weaker grip strength, and decreased activity in the beaker test. Western blot analyses indicated the downregulation of autophagy and the upregulation of mTOR activity in HHcy cortexes. HHcy also led to breeding impairments, including reduced breeding rate, in-utero fetal death, lower pups’ body weight, and increased mortality, likely attributed to placental dysfunction associated with HHcy. In conclusion, a high-Met diet impairs memory and cognition in female juveniles and weakens muscle strength in male pups. These effects may stem from abnormal placental function affecting early neurogenesis, the dysregulation of autophagy-related pathways in the cortex, or epigenetic mechanisms of gene regulation triggered by HHcy during embryonic development.
Association of Metallic and Nonmetallic Elements with Fibrin Clot Properties and Ischemic Stroke
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.
Homocysteine thiolactone and other sulfur-containing amino acid metabolites are associated with fibrin clot properties and the risk of ischemic stroke
AbstractHomocysteine (Hcy) and Hcy-thiolactone (HTL) affect fibrin clot properties and are linked to cardiovascular disease. Factors that influence fibrin clot properties and stroke are not fully understood. To study sulfur-containing amino acid metabolites, fibrin clot lysis time (CLT) and maximum absorbance (Absmax) in relation to stroke, we analyzed plasma and urine from 191 stroke patients (45.0% women, age 68 ± 12 years) and 291 healthy individuals (59.7% women, age 50 ± 17 years). Plasma and urinary levels of sulfur-containing amino acid metabolites and fibrin clot properties were significantly different in stroke patients compared to healthy individuals. Fibrin CLT correlated with fibrin Absmax in healthy males (R2 = 0.439, P = 0.000), females (R2 = 0.245, P = 0.000), female stroke patients (R2 = 0.187, P = 0.000), but not in male stroke patients (R2 = 0.008, P = ns). Fibrin CLT correlated with age in healthy females but not males while fibrin Absmax correlated with age in both sexes; these correlations were absent in stroke patients. In multiple regression analysis in stroke patients, plasma (p)CysGly, pMet, and MTHFR A1298C polymorphism were associated with fibrin Absmax, while urinary (u)HTL, uCysGly, and pCysGly were significantly associated with fibrin CLT. In healthy individuals, uHTL and uGSH were significantly associated with fibrin Absmax, while pGSH, and CBS T833C 844ins68 polymorphism were associated with fibrin CLT. In logistic regression, uHTL, uHcy, pCysGly, pGSH, MTHFR C677T polymorphism, and Absmax were independently associated with stroke. Our findings suggest that HTL and other sulfur-containing amino acid metabolites influence fibrin clot properties and the risk of stroke.