The Dark Side of an Essential Amino Acid: L-Arginine in Spinal Cord Injury

In situ mass spectrometry imaging reveals metabolite alterations in gray and white matter after spinal cord injury

It is known that spinal cord injury (SCI) causes metabolic disorders, such as disrupted lipid and amino acid metabolism. However, the in situ changes of metabolites in the spinal cord remain elusive. In the present study, adult Sprague-Dawley rats underwent spinal cord transection surgery. Ambient air flow-assisted desorption electrospray ionization mass spectrometry imaging was performed to identify the localization of metabolites in the white and gray matter and the ventral and dorsal horns within the spinal cord sections. The results revealed that 42 metabolites were specifically increased in the gray matter, and 90 metabolites were increased in the white matter compared with that in the sham group. In the ventral and dorsal horns, 86 and 103 metabolites, respectively, exhibited specific increases after injury. By contrast, numerous metabolites, especially lipids, were significantly decreased after SCI. Phosphatidylserine and phosphatidylethanolamine were mainly decreased in the gray matter, while cholesterol and ceramide were mainly decreased in the white matter. Specifically, phosphatidylethanolamine was detected at low levels in the dorsal horn following injury. However, the phosphatidylserine level decreased in the ventral horn. The functional enrichment of these metabolites via Kyoto Encyclopedia of Genes and Genomes analysis further confirmed the profile differences in the white and gray matter, as well as in the ventral and dorsal horns after SCI. These results provide valuable information on the metabolite profiles across various anatomical regions of the spinal cord following SCI, which may support the development of precise treatment strategies for patients.

Therapeutic potential of natural arginase modulators: mechanisms, challenges, and future directions

Arginase (Arg) plays a pivotal role in numerous pathological processes, with its dysregulated expression being intricately associated with tumor progression and immune evasion. This review comprehensively examines the diversity, mechanisms, and clinical potential of natural Arg modulators, encompassing polyphenols, flavonoids, and terpenoids. These bioactive compounds exert their modulatory effects on Arg activity through multiple mechanisms, including direct enzyme interaction, regulation of signaling pathways, and modulation of cellular metabolism. The therapeutic potential of these metabolites spans across various medical domains, notably in cardiovascular diseases, oncology, neurological disorders, and inflammatory conditions. Specifically, polyphenol metabolites such as resveratrol and curcumin have demonstrated significant benefits in cardiovascular health and neuroprotection, while flavonoids including rutin and quercetin have shown promising effects on intracellular inflammatory factors and tumor cell proliferation. Similarly, terpenoids like perillyl alcohol and triptolide have been found to influence cell polarization processes. However, despite their substantial therapeutic potential demonstrated in experimental studies, the development of natural Arg modulators faces several significant challenges. These include complexities in drug design attributed to the intricate structure and multiple isoforms of Arg, difficulties in elucidating precise mechanisms due to Arg's multifaceted roles in various metabolic pathways, and limitations in current drug delivery systems. To overcome these challenges, future research should focus on continuous optimization of experimental design paradigms, enhancement of experimental models and data quality, thorough evaluation of therapeutic efficacy, and strategic integration of natural Arg modulators with precision medicine approaches.

Exploring Innovative Approaches for Managing Spinal Cord Injury: A Comprehensive Review of Promising Probiotics and Postbiotics

Spinal cord injury (SCI) affects millions of people worldwide annually, presenting significant challenges in functional recovery despite therapeutic advancements. Current treatment strategies predominantly focus on stabilizing the spinal cord and facilitating neural repair, yet their effectiveness remains uncertain and controversial. Recent scientific investigations have explored the potential of probiotics and postbiotics to modulate inflammation, influence neurotransmitters, and aid in tissue repair, marking a potential paradigm shift in SCI management. This review critically evaluates these innovative approaches, emphasizing their ability to harness the natural properties of microorganisms within the body to potentially enhance outcomes in SCI treatment. By analyzing the latest research findings, this review provides valuable insights into how probiotics and postbiotics can revolutionize inflammation management and neurological recovery following SCI, underscoring their promising role in future therapeutic strategies aimed at improving the quality of life of SCI patients globally.

Biological importance of arginine: A comprehensive review of the roles in structure, disorder, and functionality of peptides and proteins

Arginine shows Jekyll and Hyde behavior in several respects. It participates in protein folding via ionic and H-bonds and cation-pi interactions; the charge and hydrophobicity of its side chain make it a disorder-promoting amino acid. Its methylation in histones; RNA binding proteins; chaperones regulates several cellular processes. The arginine-centric modifications are important in oncogenesis and as biomarkers in several cardiovascular diseases. The cross-links involving arginine in collagen and cornea are involved in pathogenesis of tissues but have also been useful in tissue engineering and wound-dressing materials. Arginine is a part of active site of several enzymes such as GTPases, peroxidases, and sulfotransferases. Its metabolic importance is obvious as it is involved in production of urea, NO, ornithine and citrulline. It can form unusual functional structures such as molecular tweezers in vitro and sprockets which engage DNA chains as part of histones in vivo. It has been used in design of cell-penetrating peptides as drugs. Arginine has been used as an excipient in both solid and injectable drug formulations; its role in suppressing opalescence due to liquid-liquid phase separation is particularly very promising. It has been known as a suppressor of protein aggregation during protein refolding. It has proved its usefulness in protein bioseparation processes like ion-exchange, hydrophobic and affinity chromatographies. Arginine is an amino acid, whose importance in biological sciences and biotechnology continues to grow in diverse ways.