The interplay between the human innate immune system and bacterial cell wall components is pivotal in understanding diseases such as Crohn\'s disease and Lyme arthritis. Lyme disease, caused by Borrelia burgdorferi, is the most prevalent tick-borne illness in the United States, with a substantial number of cases reported annually. While antibiotic treatments are generally effective, approximately 10% of Lyme disease cases develop persistent arthritis, suggesting a dysregulated host immune response. We have previously identified a link between the immunogenic B. burgdorferi peptidoglycan (PG) and Lyme arthritis and showed that this pathogen sheds significant amounts of PG fragments during growth. Here, we synthesize these PG fragments, including ornithine-containing monosaccharides and disaccharides, to mimic the unique composition of Borrelia cell walls, using reproducible and rigorous synthetic methods. This synthetic approach allows for the modular preparation of PG derivatives, providing a diverse library of well-defined fragments. These fragments will serve as valuable tools for investigating the role of PG-mediated innate immune response in Lyme disease and aid in the development of improved diagnostic methods and treatment strategies.

Surfactants are amphiphilic molecules that are capable of mixing water and oil. Biosurfactants are eco-friendly, low-toxicity, and stable to a variety of environmental factors. Optimizing conditions for microorganisms to produce biosurfactants can lead to improved production suitable for scaling up. In this study, we compared heterologous expression levels of the luminescence system luxCDABE operon controlled by regulatable promoters araC-PBAD and its strong version araC-PBAD-SD in Escherichia coli K12, Pseudomonas aeruginosa PAO1, and P. putida KT2440. Real-time monitoring of luminescence levels in the three strains indicated that luxCDABE controlled by araC-PBAD-SD promoter with 0.2% arabinose supplementation in P. putida produced the highest level of luminescence. By using the araC-PBAD-SD promoter-controlled rhlAB expression in P. putida, we were able to produce mono-rhamnolipid at a level of 1.5 g L-1 when 0.02% arabinose was supplemented. With the same system to express olsB, lyso-ornithine lipid was produced at a level of 10 mg L-1 when 0.2% arabinose was supplemented. To our knowledge, this is the first report about optimizing conditions for lyso-ornithine lipid production at a level up to 10 mg L-1. Taken together, our results demonstrate that regulatable araC-PBAD-SD promoter in P. putida KT2440 is a useful system for heterologous production of biosurfactants.

The gyrate atrophy of the choroid and retina (GACR) is a rare genetic disease for which no definitive cure is available. GACR is due to the deficit of ornithine aminotransferase (hOAT), a pyridoxal 5\'-phosphate-dependent enzyme responsible for ornithine catabolism. The hallmark of the disease is plasmatic ornithine accumulation, which damages retinal epithelium leading to progressive vision loss and blindness within the fifth decade. Here, we characterized the biochemical properties of tetrameric and dimeric hOAT and evaluated hOAT loaded in red blood cells (RBCs) as a possible enzyme replacement therapy (ERT) for GACR. Our results show that (i) hOAT has a relatively wide specificity for amino acceptors, with pyruvate being the most suitable candidate for ornithine catabolism within RBCs; (ii) both the tetrameric and dimeric enzyme can be loaded in RBC retaining their activity; and (iii) hOAT displays reduced stability in plasma, but is partly protected from inactivation upon incubation in a mixture mimicking the intracellular erythrocyte environment. Preliminary ex vivo experiments indicate that hOAT-loaded RBCs are able to metabolize extracellular ornithine at a concentration mimicking that found in patients, both in buffer and, although with lower efficiency, in plasma. Overall, our data provide a proof of concept that an RBC-mediated ERT is feasible and can be exploited as a new therapeutic approach in GACR.

UNASSIGNED: The Hand, Foot and Mouth Disease (HFMD), caused by enterovirus 71 infection, is a global public health emergency. Severe HFMD poses a significant threat to the life and well-being of children. Numerous studies have indicated that the occurrence of severe HFMD is associated with cytokine storm. However, the precise molecular mechanism underlying cytokine storm development remains elusive, and there are currently no safe and effective treatments available for severe HFMD in children.
UNASSIGNED: In this study, we established a mouse model of severe HFMD to investigate the molecular mechanisms driving cytokine storm. We specifically analyzed metabolic disturbances, focusing on arginine/ornithine metabolism, and assessed the potential therapeutic effects of spermine, an ornithine metabolite.
UNASSIGNED: Our results identified disturbances in arginine/ornithine metabolism as a pivotal factor driving cytokine storm onset in severe HFMD cases. Additionally, we discovered that spermine effectively mitigated the inflammatory injury phenotype observed in mice with severe HFMD.
UNASSIGNED: In conclusion, our findings provide novel insights into the molecular mechanisms underlying severe HFMD from a metabolic perspective while offering a promising new strategy for its safe and effective treatment.

BACKGROUND: Despite improved glycemic treatment, the impact of glycation on pathological consequences may persist and contribute to adverse clinical outcomes in diabetes. In the present study we investigated the association between serum protein glycation products and progression of kidney disease as well as incident major adverse cardiovascular events (MACE) in type 1 diabetes.
METHODS: Fructosamine, advanced glycation end products (AGEs), and methylglyoxal-modified hydro-imidazolone (MG-H1) were measured from baseline serum samples in the FinnDiane study (n = 575). Kidney disease progression was defined as steep eGFR decline (> 3 mL/min/1.73 m2/year) or progression of albuminuria (from lower to higher stage of albuminuria). MACE was defined as acute myocardial infarction, coronary revascularization, cerebrovascular event (stroke), and cardiovascular death.
RESULTS: Fructosamine was independently associated with steep eGFR decline (OR 2.15 [95% CI 1.16-4.01], p = 0.016) in the fully adjusted model (age, sex, baseline eGFR). AGEs were associated with steep eGFR decline (OR 1.58 per 1 unit of SD [95% CI 1.07-2.32], p = 0.02), progression to end-stage kidney disease (ESKD) (HR 2.09 per 1 unit of SD [95% CI 1.43-3.05], p < 0.001), and pooled progression (to any stage of albuminuria) (HR 2.72 per 1 unit of SD [95% CI 2.04-3.62], p < 0.001). AGEs (HR 1.57 per 1 unit of SD [95% CI 1.23-2.00], p < 0.001) and MG-H1 (HR 4.99 [95% CI 0.98-25.55], p = 0.054) were associated with incident MACE. MG-H1 was also associated with pooled progression (HR 4.19 [95% CI 1.11-15.89], p = 0.035). Most AGEs and MG-H1 associations were no more significant after adjusting for baseline eGFR.
CONCLUSIONS: Overall, these findings suggest that protein glycation products are an important risk factor for target organ damage in type 1 diabetes. The data provide further support to investigate a potential causal role of serum protein glycation in the progression of diabetes complications.

UNASSIGNED: Proliferative diabetic retinopathy (PDR) is a common diabetes complication, significantly impacting vision and quality of life. Previous studies have suggested a potential link between arginine pathway metabolites and diabetic retinopathy (DR). Connective tissue growth factor (CTGF) plays a role in the occurrence and development of fibrovascular proliferation (FVP) in PDR patients. However, the relationship between arginine pathway metabolites and FVP in PDR remains undefined. This study aimed to explore the correlation between four arginine pathway metabolites (arginine, asymmetric dimethylarginine[ADMA], ornithine, and citrulline) and the severity of FVP in PDR patients.
UNASSIGNED: In this study, plasma and aqueous humor samples were respectively collected from 30 patients with age-related cataracts without diabetes mellitus (DM) and from 85 PDR patients. The PDR patients were categorized as mild-to-moderate or severe based on the severity of fundal FVP. The study used Kruskal-Wallis test to compare arginine, ADMA, ornithine, and citrulline levels across three groups. Binary logistic regression identified risk factors for severe PDR. Spearman correlation analysis assessed associations between plasma and aqueous humor metabolite levels, and between ADMA and CTGF levels in aqueous humor among PDR patients.
UNASSIGNED: ADMA levels in the aqueous humor were significantly greater in patients with severe PDR than in those with mild-to-moderate PDR(P=0.0004). However, the plasma and aqueous humor levels of arginine, ornithine, and citrulline did not significantly differ between mild-to-moderate PDR patients and severe PDR patients (P>0.05). Binary logistic regression analysis indicated that the plasma (P=0.01) and aqueous humor (P=0.006) ADMA levels in PDR patients were risk factors for severe PDR. Furthermore, significant correlations were found between plasma and aqueous humor ADMA levels (r=0.263, P=0.015) and between aqueous humor ADMA and CTGF levels (r=0.837, P<0.001).
UNASSIGNED: Elevated ADMA levels in plasma and aqueous humor positively correlate with the severity of FVP in PDR, indicating ADMA as a risk factor for severe PDR.

In Japan, the promotion of effective use of many wild deer as food resource has been conducted. However, they are not necessarily utilized effectively. Thus, we focused physiologically functional compounds to find characteristics of Sika deer meats (commercially available) obtained from different regions such as Hokkaido, Wakayama, Tokushima, and Miyazaki prefectures in Japan, making it a valuable resource for future studies and applications. The amount of carnosine, anserine, and balenine in muscle of deer from Wakayama prefecture was significantly lower than that in muscle of deer from other prefectures. The differences of amount of imidazole dipeptides in different prefectures seems to be caused by feed, rearing environment, and breed. The amount of carnitine in deer meat from Hokkaido was significantly lower than that in muscle of deer from other prefectures, while the amount of acetyl-carnitine in deer meat from Miyazaki prefectures was significantly higher than that from other prefectures. The amounts of glutamine, ornithine, and 3-methylhistidine in muscles of deer from Wakayama prefectures were significantly higher than those in muscle of deer from other prefectures. These results might be caused by differences in feeding habits, habitat, the muscle types, and subspecies of deer obtained from four regions in Japan.

Glucoselysine (GL) is an unique advanced glycation end-product derived from fructose. The main source of fructose in vivo is the polyol pathway, and an increase in its activity leads to diabetic complications. Here, we aimed to demonstrate that GL can serve as an indicator of the polyol pathway activity. Additionally, we propose a novel approach for detecting GL in peripheral blood samples using liquid chromatography-tandem mass spectrometry and evaluate its clinical usefulness. We successfully circumvent interference from fructoselysine, which shares the same molecular weight as GL, by performing ultrafiltration and hydrolysis without reduction, successfully generating adequate peaks for quantification in serum. Furthermore, using immortalized aldose reductase KO mouse Schwann cells, we demonstrate that GL reflects the downstream activity of the polyol pathway and that GL produced intracellularly is released into the extracellular space. Clinical studies reveal that GL levels in patients with type 2 diabetes are significantly higher than those in healthy participants, while Nδ-(5-hydro-5-methyl-4-imidazolon-2-yl)ornithine (MG-H1) levels are significantly lower. Both GL and MG-H1 show higher values among patients with vascular complications; however, GL varies more markedly than MG-H1 as well as hemoglobin A1c, fasting plasma glucose, and estimated glomerular filtration rate. Furthermore, GL remains consistently stable under various existing drug treatments for type 2 diabetes, whereas MG-H1 is impacted. To the best of our knowledge, we provide important insights in predicting diabetic complications caused by enhanced polyol pathway activity via assessment of GL levels in peripheral blood samples from patients.

OBJECTIVE: Gyrate atrophy of the choroid and retina (GACR) is an autosomal recessive inherited metabolic disorder (IMD) characterised by progressive retinal degeneration, leading to severe visual impairment. The rapid developments in ophthalmic genetic therapies warrant knowledge on clinical phenotype of eligible diseases such as GACR to define future therapeutic parameters in clinical trials.
METHODS: Retrospective chart analysis was performed in nineteen patients. Data were analysed using IBM SPSS Statistics version 28.0.1.1.
RESULTS: Nineteen patients were included with a mean age of 32.6 years (range 8-58). Mean age at onset of ophthalmic symptoms was 7.9 years (range 3-16). Median logMAR of visual acuity at inclusion was 0.26 (range -0.18-3.00). Mean age at cataract surgery was 28.8 years (n = 11 patients). Mean spherical equivalent of the refractive error was -8.96 (range -20.87 to -2.25). Cystoid maculopathy was present in 68% of patients, with a loss of integrity of the foveal ellipsoid zone (EZ) in 24/38 eyes. Of the 14 patients treated with dietary protein restriction, the four patients who started the diet before age 10 showed most benefit.
CONCLUSIONS: This study demonstrates the severe ophthalmic disease course associated with GACR, as well as possible benefit of early dietary treatment. In addition to visual loss, patients experience severe myopia, early-onset cataract, and CME. There is a loss of foveal EZ integrity at a young age, emphasising the need for early diagnosis enabling current and future therapeutic interventions.

Hyperornithinemia-hyperammonemia-homocitrullinuria syndrome is an extremely rare disorder of urea cycle, with few patients reported worldwide. Despite hyperammonemia control, the long-term outcome remains poor with progressive neurological deterioration. We report the clinical, biochemical, and molecular features of two Lebanese siblings diagnosed with this disorder and followed for 8 and 15 years, respectively. Variable clinical manifestations and neurological outcome were observed. The patient with earlier onset of symptoms had a severe neurological deterioration while the other developed a milder form of the disease at an older age. Diagnosis was challenging in the absence of the complete biochemical triad and the non-specific clinical presentations. Whole exome sequencing revealed a homozygous variant, p.Phe188del, in the SLC25A15 gene, a French- Canadian founder mutation previously unreported in Arab patients. Hyperammonemia was controlled in both patients but hyperonithinemia persisted. Frequent hyperalaninemia spikes and lactic acidosis occured concomitantly with the onset of seizures in one of the siblings. Variable neurological deterioration and outcome were observed within the same family. This is the first report from the Arab population of the long-term outcome of this devastating neurometabolic disorder.