Oxidative stress is a crucial pathological basis for diverse intestinal diseases, such as inflammatory bowel disease (IBD). Previous studies show that Lactobacillus johnsonii RS-7 alleviates colitis in mice, but its effect on intestinal oxidative stress remains unclear. Considering this, the research aimed to explore the role and mechanism of this strain in alleviating oxidative damage in a colitis model. Colitis was induced in the mice using dextran sulfate sodium (DSS), and mice were subsequently randomly assigned to four groups. L. johnsonii RS-7 was evaluated for its effects on colon damage, oxidative stress, the Nrf2 pathway, and intestinal metabolites using histopathology, biochemical assays, qPCR, Western blotting, and non-targeted metabolomics. The results showed that L. johnsonii RS-7 significantly attenuated DSS-induced colonic tissue injury and reversed the DSS-associated decreases in serum CAT, T-SOD, GSH, and T-AOC levels (p < 0.05), along with an increase in malondialdehyde (MDA) (p < 0.05). Moreover, the strain significantly mitigated the down-regulation of antioxidant enzyme mRNA expression in colonic tissues (p < 0.05). Mechanistically, L. johnsonii RS-7 restored expression of Nrf2, NQO1, and HO-1 proteins in the colon and suppressed the up-regulation of Keap1. Non-targeted metabolomic analysis of intestinal contents further demonstrated that the strain significantly reduced levels of LPS 18:0 and triglycerides while concurrently increasing concentrations of DL-lysine and 5-hydroxylysine (p < 0.05). Correlation analysis indicated that LPS 18:0 and DL-lysine might be key metabolites regulating oxidative stress. The above results suggest that L. johnsonii RS-7 can alleviate colonic oxidative damage by regulating metabolites to activate the Nrf2 pathway, providing theoretical support for applying this strain to prevent intestinal diseases.

Glutaric aciduria type I (GA-I) is an autosomal recessive disorder affecting the metabolism of lysine, hydroxylysine, and tryptophan. Patients present in the first age of life with an irreversible motor disorder, and neuroradiological imaging can suggest the presence of the condition. Biochemically, the disorder is characterized by elevated levels of glutaric and 3-hydroxy glutaric acid in the urine and glutarylcarnitine in the blood. This latter metabolite can be detected in dried blood spots, and the condition can therefore be included in some newborn screening programs. We present the case of a patient affected by GA-I that was undetected by newborn screening in whom the diagnosis was clinically oriented at the age of nine months by acute neurological symptoms, represented by persistent tonic seizures, and by neuroimaging showing bilateral signal alterations in the basal ganglia. Biochemical data, including glutarylcarnitine in dried blood spots and urinary excretion of glutaric acid, were normal in the acute phase and during follow-up. Molecular analysis confirmed a diagnosis of GA-I, showing a homozygous M405V variant of the GCDH gene, which is common in African populations and associated with a low-excretor phenotype characteristic of the disorder. In conclusion, although GA-I is included in neonatal screening programs, the biochemical markers in dried blood spots can be absent. Therefore, in patients of African origin, clinicians should maintain a high degree of vigilance in the presence of suggestive clinical and neuroradiological findings, even if biochemical parameters are normal.

Collagen IV, an essential and evolutionarily conserved component of basement membranes, is one of the most extensively post-translationally modified proteins. Despite substantial research on fibrillar collagen biosynthesis, our understanding of collagen IV biosynthesis, including its post-translational modifications (PTMs), remains limited. Most PTMs occur intracellularly, primarily within the endoplasmic reticulum (ER). In this review, we examine the molecular ensemble that orchestrates collagen IV biosynthesis in the ER, highlighting the complex interplay between prolyl and lysyl hydroxylases, glycosyltransferases, and molecular chaperones. Furthermore, we discuss how defects in collagen IV and its PTMs contribute to various human pathologies, including Gould and Alport syndromes, fibrosis, and cancer. Understanding collagen IV PTMs is crucial for elucidating the molecular basis of these diseases and improving targeted treatments. By reviewing our knowledge of collagen IV biosynthesis, we illustrate how this evolutionarily conserved yet highly specialized molecular biosynthesis ensemble supports the diverse functions of collagen IV in health and disease.

Glutaric Aciduria type I (GA1) is a rare neurometabolic disorder caused by mutations in the GDCH gene encoding for glutaryl-CoA dehydrogenase (GCDH) in the catabolic pathway of lysine, hydroxylysine and tryptophan. GCDH deficiency leads to increased concentrations of glutaric acid (GA) and 3-hydroxyglutaric acid (3-OHGA) in body fluids and tissues. These metabolites are the main triggers of brain damage. Mechanistic studies supporting neurotoxicity in mouse models have been conducted. However, the different vulnerability to some stressors between mouse and human brain cells reveals the need to have a reliable human neuronal model to study GA1 pathogenesis. In the present work we generated a GCDH knockout (KO) in the human neuroblastoma cell line SH-SY5Y by CRISPR/Cas9 technology. SH-SY5Y-GCDH KO cells accumulate GA, 3-OHGA, and glutarylcarnitine when exposed to lysine overload. GA or lysine treatment triggered neuronal damage in GCDH deficient cells. SH-SY5Y-GCDH KO cells also displayed features of GA1 pathogenesis such as increased oxidative stress vulnerability. Restoration of the GCDH activity by gene replacement rescued neuronal alterations. Thus, our findings provide a human neuronal cellular model of GA1 to study this disease and show the potential of gene therapy to rescue GCDH deficiency.

Glutaric aciduria type 1 (GA1) is an organic aciduria inherited in an autosomal recessive pattern, with an occurrence rate of one in 100,000. It is caused by a deficiency of the enzyme glutaryl-CoA dehydrogenase (GCDH), encoded by the GCDH gene on chromosome 19. It is an important enzyme in the catabolism of amino acids such as tryptophan, lysine, and hydroxylysine. Its deficiency leads to the accumulation of organic acids such as glutaric acid and 3-hydroxyglutaric acid, which interfere with cerebral energy metabolism and cause neurological symptoms. Here, we discuss the case of a six-month-old male child who presented with status epilepticus following an eight-day history of fever. The child was started on anti-epileptics. Initially, the child was on non-invasive ventilation and was later intubated and taken on a mechanical ventilator. A magnetic resonance imaging (MRI) scan of the brain was performed, and the findings suggested GA1. The child was started on carnitine after samples were sent for tandem mass spectrometry (TMS) and urine gas chromatography-mass spectrometry (GC/MS), which came out to be positive for GA1. Despite the timely intervention, the child did not survive. Most cases exhibit movement disorders, with many presenting in acute encephalitic crises. Additionally, a significant portion of patients experience an insidious onset of the disease. An MRI of the brain shows widened Sylvian fissures in the majority of cases. Treatment of GA1 includes dietary modifications, including a low-lysine diet and administering carnitine. Early diagnosis and management result in decreased mortality and morbidity, which underscores the need for newborn screening.