Hyperhomocysteinemia and Bleomycin Hydrolase Modulate the Expression of Mouse Brain Proteins Involved in Neurodegeneration

Abstract

Homocysteine (Hcy) is a risk factor for Alzheimer's disease (AD). Bleomycin hydrolase (BLMH) participates in Hcy metabolism and is also linked to AD. The inactivation of the Blmh gene in mice causes accumulation of Hcy-thiolactone in the brain and increases susceptibility to Hcy-thiolactone-induced seizures. To gain insight into brain-related Blmh function, we used two-dimensional IEF/SDS-PAGE gel electrophoresis and MALDI-TOF/TOF mass spectrometry to examine brain proteomes of Blmh-/- mice and their Blmh+/+ littermates fed with a hyperhomocysteinemic high-Met or a control diet. We found that: (1) proteins involved in brain-specific function (Ncald, Nrgn, Stmn1, Stmn2), antioxidant defenses (Aop1), cell cycle (RhoGDI1, Ran), and cytoskeleton assembly (Tbcb, CapZa2) were differentially expressed in brains of Blmh-null mice; (2) hyperhomocysteinemia amplified effects of the Blmh-/- genotype on brain protein expression; (3) proteins involved in brain-specific function (Pebp1), antioxidant defenses (Sod1, Prdx2, DJ-1), energy metabolism (Atp5d, Ak1, Pgam-B), and iron metabolism (Fth) showed differential expression in Blmh-null brains only in hyperhomocysteinemic animals; (4) most proteins regulated by the Blmh-/- genotype were also regulated by high-Met diet, albeit in the opposite direction; and (5) the differentially expressed proteins play important roles in neural development, learning, plasticity, and aging and are linked to neurodegenerative diseases, including AD. Taken together, our findings suggest that Blmh interacts with diverse cellular processes from energy metabolism and anti-oxidative defenses to cell cycle, cytoskeleton dynamics, and synaptic plasticity essential for normal brain homeostasis and that modulation of these interactions by hyperhomocysteinemia underlies the involvement of Hcy in AD.

Paraoxonase 1 deficiency and hyperhomocysteinemia alter the expression of mouse kidney proteins involved in renal disease

“…These findings suggest that while in the kidney and liver the antioxidant defense is enhanced by a high-Met diet, in the brain the antioxidant defense is compromised. The other proteins that were identified as differentially expressed in the kidney (Table 1) were not regulated by the Pon1 −/− genotype and/or high-Met diet in the liver [24] or brain [25]. Pebp1 was up-regulated in the kidney and down-regulated in the brain both by the Pon1 −/− genotype and highMet diet (Supplementary Table S2).…”

“…Protein sample preparation, 2D-IEF/SDS-PAGE analyses, and protein identification by MALDI-TOF mass spectrometry [23][24][25] were carried out as described in the Supplementary Methods.…”

Homocysteine thiolactone and N-homocysteinylated protein induce pro-atherogenic changes in gene expression in human vascular endothelial cells

“…In humans and mice, HHcy leads to the accumulation of Hcy-thiolactone and N -Hcy-protein, in addition to Hcy (Chwatko et al 2007 ; Jakubowski et al 2008 , 2009 ). We and other investigators have shown that HHcy induces changes in gene expression in mouse models that are associated with atherothrombotic disease (Devlin et al 2005 ; DiBello et al 2010 ; Ingrosso et al 2003 ; Kim et al 2011 ; Pogribny et al 2008 ; Sharma et al 2006 ; Suszynska-Zajczyk et al 2014a , b , c , d ). However, it is not known what mechanism(s) are involved and which metabolite—Hcy itself, Hcy-thiolactone, or N -Hcy-protein—is responsible for changes in gene expression.…”

Gene expression profiling for human iPS-derived motor neurons from sporadic ALS patients reveals a strong association between mitochondrial functions and neurodegeneration

“…However, some (eg. ATP5D, ATP5E, NDUFA4, NDUFB5, NDUFB6) have been implicated in other neurodegenerative disorders (Chen et al, 2014 ; Suszyńska-Zajczyk et al, 2014 ). Additionally, NDUFC2, ND2, COX7C, NDUFV3, SDHC, ATP5C1, COX6A1, ATP4B, ATP6V1D , and COX17 are associated with mitochondrial function or impaired bioenergetic metabolism, and thus further support a role for mitochondrial dysfunction in the cell autonomous degeneration of motor neurons in sporadic ALS (Burman et al, 2014 ).…”