[Linker histones H1 in human disease].

Linker histones (H1) are basic proteins that are part of the nucleosome structure in the cell nucleus and are involved in the packaging of genetic material and the regulation of gene expression. As research progressed, it was discovered that linker histones constitute the largest group of histones in terms of variants found in humans. Even though the H1 variants differ slightly in the primary structure, they can perform different functions, undergo multiple post-translational modifications and differ in cellular localization.

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 (Abs) in relation to ischemic stroke. Design-A case-control study of ischemic stroke patients vs.

Homocysteine thiolactone and other sulfur-containing amino acid metabolites are associated with fibrin clot properties and the risk of ischemic stroke.

Homocysteine (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 (Abs) in relation to stroke, we analyzed plasma and urine from 191 stroke patients (45.

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.

Homocysteine thiolactone contributes to the prognostic value of fibrin clot structure/function in coronary artery disease.

Fibrin clot structure/function contributes to cardiovascular disease. We examined sulfur-containing metabolites as determinants of fibrin clot lysis time (CLT) and maximum absorbance (Absmax) in relation to outcomes in coronary artery disease (CAD) patients. Effects of B-vitamin/folate therapy on CLT and Absmax were studied.

COVID-19 and One-Carbon Metabolism.

Dysregulation of one-carbon metabolism affects a wide range of biological processes and is associated with a number of diseases, including cardiovascular disease, dementia, neural tube defects, and cancer. Accumulating evidence suggests that one-carbon metabolism plays an important role in COVID-19. The symptoms of long COVID-19 are similar to those presented by subjects suffering from vitamin B deficiency (pernicious anemia).

B Vitamins Prevent Iron-Associated Brain Atrophy and Domain-Specific Effects of Iron, Copper, Aluminum, and Silicon on Cognition in Mild Cognitive Impairment.

Background:: Metals, silicon, and homocysteine are linked to Alzheimer’s disease. B vitamin therapy lowers homocysteine and slows brain atrophy and cognitive decline in mild cognitive impairment (MCI).

Objective:: Examine metals and silicon as predictors of cognition/brain atrophy in MCI, their interaction with homocysteine and cysteine, and how B vitamins affect these relationships.

Paraoxonase 1, B Vitamins Supplementation, and Mild Cognitive Impairment.

Background: Identification of modifiable risk factors that affect cognitive decline is important for the development of preventive and treatment strategies. Status of paraoxonase 1 (PON1), a high-density lipoprotein-associated enzyme, may play a role in the development of neurological diseases, including Alzheimer's disease.

Objective: We tested a hypothesis that PON1 status predicts cognition in individuals with mild cognitive impairment (MCI).

Anti--homocysteine-protein autoantibodies are associated with impaired cognition.

Introduction: Elevated homocysteine (Hcy) and related metabolites accelerate Alzheimer's disease. Hcy-lowering B vitamins slow brain atrophy/cognitive decline in mild cognitive impairment (MCI). Modification with Hcy-thiolactone generates auto-immunogenic -Hcy-protein.

Genetic Attenuation of Paraoxonase 1 Activity Induces Proatherogenic Changes in Plasma Proteomes of Mice and Humans.

High-density lipoprotein (HDL), in addition to promoting reverse cholesterol transport, possesses anti-inflammatory, antioxidative, and antithrombotic activities. Paraoxonase 1 (PON1), carried on HDL in the blood, can contribute to these antiatherogenic activities. The - polymorphism involves a change from glutamine (Q variant) to arginine (R variant) at position 192 of the PON1 protein and affects its enzymatic activity.

Telomere length and mtDNA copy number in human cystathionine β-synthase deficiency.

Telomere shortening and mitochondrial DNA (mtDNA) copy number are associated with human disease and a reduced life span. Cystathionine β-synthase (CBS) is a housekeeping enzyme that catalyzes the first step in metabolic conversion of homocysteine (Hcy) to cysteine. Mutations in the CBS gene cause CBS deficiency, a rare recessive metabolic disease, manifested by severe hyperhomocysteinemia (HHcy) and thromboembolism, which ultimately reduces the life span.

The Cbs Locus Affects the Expression of Senescence Markers and mtDNA Copy Number, but not Telomere Dynamics in Mice.

Cystathionine β-synthase (CBS) is a housekeeping enzyme that catalyzes the first step of the homocysteine to cysteine transsulfuration pathway. Homozygous deletion of the gene in mice causes severe hyperhomocysteinemia and reduces life span. Here, we examined a possible involvement of senescence, mitochondrial DNA, and telomeres in the reduced life span of mice.

Dysregulation of Epigenetic Mechanisms of Gene Expression in the Pathologies of Hyperhomocysteinemia.

Hyperhomocysteinemia (HHcy) exerts a wide range of biological effects and is associated with a number of diseases, including cardiovascular disease, dementia, neural tube defects, and cancer. Although mechanisms of HHcy toxicity are not fully uncovered, there has been a significant progress in their understanding. The picture emerging from the studies of homocysteine (Hcy) metabolism and pathophysiology is a complex one, as Hcy and its metabolites affect biomolecules and processes in a tissue- and sex-specific manner.

Sex affects N-homocysteinylation at lysine residue 212 of albumin in mice.

The modification of protein lysine residues by the thioester homocysteine (Hcy)-thiolactone has been implicated in cardiovascular and neurodegenerative diseases. However, only a handful of proteins carrying Hcy on specific lysine residues have been identified and quantified in humans or animals. In the present work, we developed a liquid chromatography/mass spectrometry targeted assay, based on multiple reaction monitoring, for quantification of N-Hcy-Lys212 (K212Hcy) and N-Hcy-Lys525 (K525Hcy) sites in serum albumin in mice.

Paraoxonase 1 Q192R genotype and activity affect homocysteine thiolactone levels in humans.

Genetic or nutritional deficiencies in 1 carbon and homocysteine (Hcy) metabolism elevate Hcy-thiolactone levels and are associated with cardiovascular and neurologic diseases. Hcy-thiolactone causes protein damage, cellular toxicity, and proatherogenic changes in gene expression in human cells and tissues. A polymorphic cardio-protective enzyme, paraoxonase 1 (PON1), hydrolyzes Hcy-thiolactone in vitro.

N-Homocysteinylation impairs collagen cross-linking in cystathionine β-synthase-deficient mice: a novel mechanism of connective tissue abnormalities.

Cystathionine β-synthase (CBS) deficiency, a genetic disorder in homocysteine (Hcy) metabolism in humans, elevates plasma Hcy-thiolactone and leads to connective tissue abnormalities that affect the cardiovascular and skeletal systems. However, the underlying mechanism of these abnormalities is not understood. Hcy-thiolactone has the ability to form isopeptide bonds with protein lysine residues, which generates N-homocysteinylated protein.

Paraoxonase 1 and homocysteine metabolism.

Paraoxonase 1 (PON1), a component of high-density lipoprotein (HDL), is a calcium-dependent multifunctional enzyme that connects metabolisms of lipoproteins and homocysteine (Hcy). Both PON1 and Hcy have been implicated in human diseases, including atherosclerosis and neurodegeneration. The involvement of Hcy in disease could be mediated through its interactions with PON1.

Cation exchange HPLC analysis of desmosines in elastin hydrolysates.

Desmosine crosslinks are responsible for the elastic properties of connective tissues in lungs and cardiovascular system and are often compromised in disease states. We developed a new, fast, and simple cation exchange HPLC assay for the analysis of desmosine and isodesmosine in animal elastin. The method was validated by determining linearity, accuracy, precision, and desmosines stability and was applied to measure levels of desmosines in porcine and murine organs.

Properties of Escherichia coli EF-Tu mutants designed for fluorescence resonance energy transfer from tRNA molecules.

Here we describe the design, preparation and characterization of 10 EF-Tu mutants of potential utility for the study of Escherichia coli elongation factor Tu (EF-Tu) interaction with tRNA by a fluorescence resonance energy transfer assay. Each mutant contains a single cysteine residue at positions in EF-Tu that are proximal to tRNA sites within the aminoacyl-tRNA.EF-Tu.

Paraoxonase 1 protects against protein N-homocysteinylation in humans.

Genetic or nutritional disorders in homocysteine (Hcy) or folate metabolism elevate plasma Hcy-thiolactone and lead to vascular and/or brain pathologies. Hcy-thiolactone has the ability to form isopeptide bonds with protein lysine residues, which generates N-Hcy-protein with autoimmunogenic and prothrombotic properties. Paraoxonase (PON1), carried on high-density lipoproteins (HDLs) in the blood, hydrolyzes Hcy-thiolactone and protects against the accumulation of N-Hcy-protein in vitro.

Genetic or nutritional disorders in homocysteine or folate metabolism increase protein N-homocysteinylation in mice.

Genetic disorders of homocysteine (Hcy) or folate metabolism or high-methionine diets elevate plasma Hcy and its atherogenic metabolite Hcy-thiolactone. In humans, severe hyperhomocysteinemia due to genetic alterations in cystathionine beta-synthase (Cbs) or methylenetetrahydrofolate reductase (Mthfr) results in neurological abnormalities and premature death from vascular complications. In mouse models, dietary or genetic hyperhomocysteinemia results in liver or brain pathological changes and accelerates atherosclerosis.

Immunohistochemical detection of N-homocysteinylated proteins in humans and mice.

N-homocysteinylation of epsilon-amino group of protein lysine residues by homocysteine (Hcy) thiolactone has been implicated in vascular disease in humans. We have previously generated polyclonal rabbit anti-N-Hcy-protein IgG antibodies that specifically recognize the Nepsilon-Hcy-Lys epitope on N-homocysteinylated proteins. The present work was undertaken to examine the utility of these antibodies for the immunohistochemical detection of N-homocysteinylated proteins in biological samples.

Modification by homocysteine thiolactone affects redox status of cytochrome C.

Homocysteine (Hcy)-thiolactone mediates a post-translational incorporation of Hcy into protein in humans. Protein N-homocysteinylation is detrimental to protein structure and function and is linked to pathophysiology of hyperhomocysteinemia observed in humans and experimental animals. The modification by Hcy-thiolactone can be detrimental directly by affecting the function of an essential lysine residue or indirectly by interfering with the function of other essential residues or cofactors.