γ-aminobutyric acid receptor B signaling drives glioblastoma in females in an immune-dependent manner.

Sex differences in immune responses impact cancer outcomes and treatment response, including in glioblastoma (GBM). However, host factors underlying sex specific immune-cancer interactions are poorly understood. Here, we identify the neurotransmitter γ-aminobutyric acid (GABA) as a driver of GBM-promoting immune response in females. We demonstrated that GABA receptor B (GABBR) signaling enhances L-Arginine metabolism and nitric oxide synthase 2 (NOS2) expression in female granulocytic myeloid-derived suppressor cells (gMDSCs). GABBR agonist and GABA analog promoted GBM growth in females in an immune-dependent manner, while GABBR inhibition reduces gMDSC NOS2 production and extends survival only in females. Furthermore, female GBM patients have enriched GABA transcriptional signatures compared to males, and the use of GABA analogs in GBM patients is associated with worse short-term outcomes only in females. Collectively, these results highlight that GABA modulates anti-tumor immune response in a sex-specific manner, supporting future assessment of GABA pathway inhibitors as part of immunotherapy approaches.

Synthesis and Application of Titanium Carbide (Ti3C2)-Cobalt Sulfide (Co3S4) Nanocomposites in Amino Acid Biosensing.

Background The fabrication of titanium carbide (Ti3C2)-cobalt sulfide (Co3S4)-based biosensors with high sensitivity and selectivity can change the biosensor manufacturing industry completely. Molecular and clinical diagnostics, disease progression monitoring, and drug discovery could utilize these sensors for early biomarker detection. MXene (Ti3C2) is a two-dimensional material with exceptional electrical conductivity, hydrophilicity, great thermal stability, large interlayer spacing, and a high surface area. Ti3C2's remarkable characteristics make it well-suited for biomolecule immobilization and target analyte detection. Co3S4 is a transition metal chalcogenide that has shown great potential in biosensors. Co3S4 nanoparticles (NPs) can potentially enhance Ti3C2 electrocatalytic activity, particularly in amino acid detection. L-arginine is a semi-essential amino acid, and the body frequently uses it to support healthy circulation and plays a crucial role in protein synthesis. We fabricated the Ti3C2-Co3S4 biosensor for L-arginine detection. Aim  This study aims to synthesize and apply Ti3C2-Co3S4 nanocomposites in amino acid biosensing. Materials and methods The Ti3C2 nanosheets were synthesized by the selective removal of an aluminum (Al) layer from the precursor (Ti3AlC2) using hydrofluoric acid (HF). The resulting mixture serves as an etchant, especially targeting the Al layers on Ti3AlC2 while protecting the desired MXene layers at room temperature. Cobalt nitrate hexahydrate was dissolved in deionized water. Sodium hydroxide was added to the cobalt solution and stirred. Thioacetamide was added to the above solution and stirred (Solution B). A mixture of Solution A and Solution B was stirred for 30 minutes. The mixture is transferred to a hydrothermal reactor and maintained at a temperature of 180°C for 12 hours. Once the reaction completes, we cool the resultant mixture to room temperature and then filter it using the washing technique. The sample underwent a 12-hour drying process at 80°C.  Results  This study investigated the use of a biosensor that employed Ti3C2-Co3S4 NPs to detect the concentration of L-arginine. The X-ray diffraction (XRD) shows clear and distinct peaks, which means that the synthesized Ti3C2-Co3S4 nanostructures have a crystalline structure. Scanning electron microscopy (SEM) analysis revealed that the sheetlike structure of synthesized Ti3C2-Co3S4 nanostructures revealed the crystalline morphology. The results of this study show that the Ti3C2-Co3S4 NP-based biosensor can be used to detect L-arginine in a sensitive and selective way. Conclusion  This study investigated the synthesis of Ti3C2-Co3S4 NPs and their ability to detect L-arginine levels and show a distinct correlation between the L-arginine concentration and the fluorescence intensity, demonstrating the biosensor's effectiveness in detecting L-arginine levels.

Comprehensive insight into exploring the potential of microbial enzymes in cancer therapy: Progress, challenges, and opportunities: A review.

Microbial enzymes are crucial catalysts in various industries due to their versatility and efficiency. The microbial enzymes market has recently expanded due to increased demand for many reasons. Among them are eco-friendly solutions, developing novel microbial strains with enhanced enzymes that perform under harsh conditions, providing sustainability, and raising awareness about the benefits of enzyme-based products. By 2030, the global enzyme market is expected to account for $525 billion, with a growth rate of 6.7 %. L-asparaginase and L-glutaminase are among the leading applied microbial enzymes in antitumor therapy, with a growing market share of 16.5 % and 9.5 %, respectively. The use of microbial enzymes has opened new opportunities to fight various tumors, including leukemia, lymphosarcoma, and breast cancer, which has increased their demand in the pharmaceutical and medicine sectors. Despite their promising applications, commercial use of microbial enzymes faces challenges such as short half-life, immunogenicity, toxicity, and other side effects. Therefore, this review explores the industrial production, purification, formulation, and commercial utilization of microbial enzymes, along with an overview of the global enzyme market. With ongoing discoveries of novel enzymes and their applications, enzyme technology offers promising avenues for cancer treatment and other therapeutic interventions.

Elucidation of the Role of L-Arginine and Nω-Nitro-L-Arginine in the Treatment of Rats with Different Levels of Hypoxic Tolerance and Exposure to Lead Nitrate.

BACKGROUND/AIMS: Individual resistance to hypoxia is an important feature of the physiological profile of an organism, particularly in relation to lead-induced toxicity. METHODS: Our study focused on evaluating parameters of mitochondrial oxygen consumption, microsomal oxidation, intensity of lipoperoxidation processes and antioxidant defences in the liver of rats with low (LR) and high (HR) resistance to hypoxia to elucidate the mechanisms of action of L-arginine and the NO synthase inhibitor L-NNA before or after exposure to lead nitrate. RESULTS: Our study suggests that the redistribution of oxygen-dependent processes towards mitochondrial processes under the influence of the nitric oxide precursor amino acid L-arginine is an important mechanism for maintaining mitochondrial respiratory chain function during per os lead nitrate exposure (3.6 mg lead nitrate/kg bw per day for 30 days). Animals were given L-arginine at a dose of 600 mg/kg bw (i.p., 30 min) before and after exposure to lead nitrate or the NO synthase inhibitor Nω-nitro-L-arginine (L-NNA) at a dose of 35 mg/kg bw (i.p., 30 min) before and after exposure to lead nitrate. Our experiments demonstrated the efficacy of using lead nitrate to simulate lead-related toxic processes via Pb levels in liver tissue; we demonstrated significantly reduced levels of nitrites and nitrates, i.e. stable metabolites of the nitric oxide system, in both LR and HR animals. The effect of the amino acid L-arginine stabilised the negative effects of lead nitrate exposure in both groups of LR and HR rats. We observed the efficiency of mitochondrial energy supply processes and showed a greater vulnerability of NADH-dependent oxidation during lead nitrate exposure in the liver of HR rats. CONCLUSION: L-arginine initiated the processes of oxidation of NADH-dependent substrates in the LR group, whereas in the HR group this directionality of processes was more effective when the role of the nitric oxide system was reduced (use of L-NNA). Our study of key antioxidant enzyme activities in rat liver tissue during lead nitrate exposure revealed changes in the catalase-peroxidase activity ratio. We found different activities of antioxidant enzymes in the liver tissue of rats treated with lead nitrate and L-arginine or L-NNA, with a significant increase in GPx activity in the LR group when L-arginine was administered both before and after exposure to lead nitrate.

Dental Caries: Unveiling the State-of-the-Art Insights and Crafting Hypotheses for Oral Health.

The pathophysiological understanding of dental caries explains that the primary factor responsible is linked to an imbalance in microbial composition within the oral cavity, stemming from both artificial and natural sources. Streptococcus mutans (S. mutans) is the most accountable and prevalent pathogen for caries development among the diverse pool. S. mutans, an acidogenic bacterium, lowers oral pH through the metabolic conversion of dietary sugar into organic acids, leading to enamel demineralization and dental caries. Numerous antibacterial interventions have been employed in the past to address this issue. However, adopting such an approach poses the risk of exacerbating concerns related to Antimicrobial Resistance (AMR) and long-term oral cytotoxicity. In response to this, a sustainable strategy is suggested, involving the utilization of L-Arginine (L-Arg) as a probiotic nutrient supplement for non-pathogenic microbes. It will help in creating a natural competitive environment against the pathogenic microbes responsible for initiating dental caries. The hypothesis involves utilizing a combination of a nutrient supplement and the repurposed drug Piceatannol, specifically for its anti-biofilm properties. This combination synergistically improves the effectiveness of the therapy by converting the complex microbial biofilm into a planktonic state.

Effects of n-hexane fraction of Piper guineense seed extract on Nω-nitro-L-arginine methyl ester hydrochloride-induced hypertension in rats.

This study aimed to investigate the effects of the n-hexane fraction of the ethanolic seed extract of PG (NFESEPG) on hypertension induced by Nω-nitro-L-arginine methyl ester (L-NAME) in rats. Specifically, the study examined the impact of NFESEPG on blood pressure, oxidative stress markers, NO concentration, angiotensin-converting enzyme (ACE) and arginase activities, and cardiac biomarkers in hypertensive rats. The study involved collecting, identifying, and processing the PG plant to obtain the ethanolic seed extract. The extract was then partitioned with solvents to isolate the n-hexane fraction. Hypertension was induced in rats by oral administration of L-NAME for 10 days, while concurrent treatment with NFESEPG at two doses (200 and 400 mg/kg/day) was administered orally. Blood pressure was measured using a noninvasive tail-cuff method, and various biochemical parameters were assessed. Treatment with both doses of NFESEPG significantly reduced systolic and diastolic blood pressure in L-NAME-induced hypertensive rats. Additionally, NFESEPG administration increased NO concentration and decreased ACE and arginase activities, malondialdehyde (MDA) levels, and cardiac biomarkers in hypertensive rats. The findings indicate that NFESEPG effectively lowered blood pressure in hypertensive rats induced by L-NAME, potentially through mechanisms involving the modulation of oxidative stress, NO bioavailability, and cardiac biomarkers. These results suggest the therapeutic potential of NFESEPG in managing hypertension and related cardiovascular complications.

Elevated Plasma Levels of Arginines During Labor Among Women with Spontaneous Preterm Birth: A Prospective Cohort Study.

PROBLEM: Preterm birth (PTB) is a leading cause of infant mortality and morbidity. The pathogenesis of PTB is complex and involves many factors, including socioeconomy, inflammation and infection. Asymmetric dimethylarginine, ADMA and symmetric dimethylarginine, SDMA are involved in labor as inhibitors of nitric oxide, a known relaxant of the uterine smooth muscles. Arginines are scarcely studied in relation to PTB and we aimed to investigate arginines (ADMA, SDMA and L-arginine) in women with spontaneous PTB and term birth. METHODS OF THE STUDY: The study was based on data from the population-based, prospective cohort BASIC study conducted in Uppsala County, Sweden, between September 2009 and November 2018. Arginines were analyzed by Ultra-High Performance Liquid Chromatography using plasma samples taken at the onset of labor from women with spontaneous PTB (n = 34) and term birth (n = 45). We also analyzed the inflammation markers CRP, TNF-R1 and TNF-R2 and GDF-15. RESULTS: Women with spontaneous PTB had higher plasma levels of ADMA (p < 0.001), and L-Arginine (p = 0.03). In addition, inflammation marker, TNF-R1 (p = 0.01) was higher in spontaneous PTB compared to term birth. Further, in spontaneous PTB, no significant correlations could be observed when comparing levels of arginines with inflammation markers, except ADMA versus CRP. CONCLUSIONS: These findings provide novel evidence for the potential involvement of arginines in the pathogenesis of spontaneous PTB and it seems that arginine levels at labor vary independently of several inflammatory markers. Further research is warranted to investigate the potential of arginines as therapeutic targets in the prevention and management of spontaneous PTB.

L-arginine attenuates dichlorvos-induced testicular toxicity in male Wistar rats by suppressing oxidative stress-dependent activation of caspase 3-mediated apoptosis.

BACKGROUND: The continuous use of pesticides, such as dichlorvos, is a common agricultural and domestic practice. However, it is associated with shortfalls like testicular toxicity through the induction of oxidative stress-mediated signaling. On the other hand, L-arginine, a precursor of nitric oxide, has been reported to exert antioxidant activities and thus may attenuate dichlorvos-induced testicular toxicity. AIM: Hence, this study was designed to evaluate the effect of L-arginine treatment on dichlorvos-induced testicular toxicity. MATERIALS AND METHODS: Forty male Wistar rats were randomly assigned into four equal groups. The control rats were administered 0.5 mL of distilled water, dichlorvos- (DDVP-) treated rats were exposed to DDVP via inhalation for 15 min, DDVP + L-arginine-treated rats were exposed to DDVP and also received 100 mg/kg b.w/day, while L-arginine-treated rats received 100 mg/kg b.w/day. RESULTS: DDVP exposure significantly reduced testicular nitric oxide, relative testicular weight, lowered sperm count, viability, and motility, and suppressed serum FSH, LH, and testosterone levels. These findings were associated with a rise in testicular malondialdehyde, TNF-α, IL-6, and 8OHdG levels and caspase 3 activities, and a reduction in GSH and superoxide dismutase. Additionally, on histopathological examination, DDVP was observed to reduce mature sperm cells in the seminiferous tubular lumen and induce focal vascular congestion in the interstitial space. Nonetheless, L-arginine treatment significantly attenuated DDVP-induced biochemical and histological alterations. CONCLUSION: This study showed that L-arginine attenuated testicular toxicity by improving epididymal sperm variables and male sex hormones by suppressing oxidative stress, inflammation, and apoptosis in DDVP-exposed rats.

Cyclodextrins and Amino Acids Enhance Solubility and Tolerability of Retinoic Acid/Tretinoin: Molecular Docking, Physicochemical, Cytotoxicity, Scratch Assay, and Topical Gel Formulations Investigation.

With increasing longevity globally, the search for effective and patient-friendly anti-aging solutions has been growing. Retinoic acid (Ret) is an FDA-approved anti-aging and anti-wrinkling formula, however, its poor solubility and poor tolerability hamper its use in cosmetically accepted formulations. In this study, cyclodextrins and arginine were investigated for improving the solubility and tolerability of retinoic acid through the formation of inclusion complexes and salt formation, respectively. Two different methods were employed: physical mixing and kneading. The prepared dispersions were investigated for molecular docking (MD), solubility, thermal and spectral analyses, cytotoxicity, and scratch assays. The optimized disperse systems were formulated in a gel formulation and characterized for rheological, in vitro release, and kinetics. The MD, DSC, and FTIR results indicated that both ß- and hydroxy propyl (HP) ß-cyclodextrins could host RA in their cavities and form inclusion complexes. Ret can form a salt with the basic amino acid arginine. Solubility studies of RA significantly (p < 0.01) enhanced by 14- to 81-fold increases with the investigated cyclodextrins and arginine. The cell viability recorded for Ret:HP ß-CD K and Ret:arginine K was significantly increased compared to that for Ret alone. The IC50% recorded for azelaic acid (mild to non-irritant control), Ret, Ret:HP ß-CD K, and Ret:arginine K were 1000, 485, 1100, and 895 µg/mL, respectively. The two carriers (HP ß-CD and the amino acid arginine) were able to significantly (p < 0.05) reduce the irritation potential of Ret. Furthermore, comparable gap closure rates were recorded for Ret alone, Ret:HP ß-CD K, and Ret:arginine K, indicating that inclusion complexation and ion pair formation reduced the irritation potentials without undermining the efficacy.

Diets containing phytobiotics, l-arginine, vitamin E and captopril modulate ascites syndrome-related genes expression in broiler chickens exposed to low ambient temperature.

BACKGROUND: Our hypothesis centred on the potential to mitigate ascites outbreaks in birds exposed to cold stress by inhibiting pulmonary artery contraction through dietary intervention. OBJECTIVE: This study aimed to evaluate the effect of natural and synthetic medications on growth performance, ascites-related parameters and the expression of ascites-related genes in the lung tissue of broiler chickens under low ambient temperature. METHODS: We randomly assigned 450 one-day-old male Ross 308 chicks to six dietary treatments across five replicate pens, each containing 15 chicks. The treatments included a basal diet (control), and the basal diet was supplemented with hydroalcoholic extracts of sumac (HES, 200 mg/kg), Syrian mesquite (HEM, 200 mg/kg), l-arginine (40% above requirement), captopril (15 mg/kg) and vitamin E (100 mg/kg). RESULTS: Diets containing HEM, l-arginine and vitamin E resulted in increased average daily gain on days 8-14 and 0-28, whereas HES showed a similar effect only during days 8-14 compared to the control diet (p < 0.05). Additionally, feed additives decreased packed cell volume, left and right ventricle volumes and systolic blood pressure (p < 0.05). Moreover, chickens fed the control and l-arginine diets exhibited higher levels of angiotensin converting enzyme (ACE) mRNA in lung tissue compared to those fed HES, HEM and captopril (p < 0.05). Meanwhile, supplementation with HEM and l-arginine increased the expression of inducible nitric oxide synthase (iNOS) mRNA in lung tissue compared to other treatments (p < 0.05). Regarding Cu/Zn-superoxide dismutase (Cu/Zn-SOD) expression, feed additives increased mRNA level in lung tissue, except for captopril (p < 0.05). CONCLUSIONS: This study demonstrates that the plant extracts may reduce the incidence of ascites syndrome not only through their antioxidant properties but also by modulating the expression of ACE, iNOS and Cu/Zn-SOD genes.

Effect of L-arginine on cystic fibrosis Pseudomonas aeruginosa biofilms.

Cystic fibrosis (CF) airways are L-arginine deficient which may affect susceptibility to infection with certain pathogens. The potential impact of L-arginine supplementation on Pseudomonas aeruginosa, a common CF airway pathogen, is unclear. This study investigated the effects of L-arginine on P. aeruginosa biofilm cultures, using the laboratory strain PAO1 and multi-drug resistant CF clinical isolates. P. aeruginosa biofilms were grown in a chambered cover-glass slide model for 24 h, then exposed to either L-arginine alone or combined with tobramycin for an additional 24 h. Biofilms were visualized using confocal microscopy, and viable cells were measured via plating for colony-forming units. Increasing concentrations of L-arginine in bacterial culture medium reduced the biovolume of P. aeruginosa in a dose-dependent manner. Notably, L-arginine concentrations within the physiological range (50 mM and 100 mM) in combination with tobramycin promoted biofilm growth, while higher concentrations (600 mM and 1200 mM) inhibited growth. These findings demonstrate the potential of L-arginine as an adjuvant therapy to inhaled tobramycin in treating P. aeruginosa infections in people with CF.

The effect of L-Arginine therapy on achilles tendon healing: A histological and biomechanical investigation in an animal model.

PURPOSE: Several clinical and experimental studies have revealed that L-Arginine, which has antioxidant properties, accelerates tissue healing. This study examined the in vivo effects of oral L - Arginine supplementation on tendon regeneration in Wistar rats. METHOD: For each weighting of an average of 250-300 g, 24 Wistar rats were separated into three equal groups. Each rat's right hind leg Achilles tendons were tenotomized and then repaired. The first group (Control) was followed up with a regimen of standard food and water. In the second group (L-Arg Low Dose), 300 mg/kg, and in the third group (L-Arg High Dose), 600 mg/kg L-Arginine was administered in water daily with a regimen of standard food and water ad libitum. After eight weeks, the rats were sacrificed, and the tendons were histologically and biomechanically analyzed. RESULTS: Tendon peak strength values of the L-Arg Low Dose and L-Arg High Dose groups were similar but significantly higher than the control group. A statistically significant difference was observed between the groups in terms of ground substance, fiber arrangement, cellularity, hyalinization, and GAG properties ( p = 0.05, p = 0.002, p = 0.016, p = 0.027, p = 0.05). There was no statistically significant difference between the groups according to the histological examination of collagen properties, fiber structure, tenocyte properties, rounding of the nuclei, and collagen stainability. (p = 0.999, p = 0.061, p = 0.195, p = 0.195, p = 0.130). No mortality, wound complications, or re-ruptures were observed. CONCLUSION: Compared with the control group, histologically and biomechanically distinct therapeutic effects of L-Arginine supplementation on tendon healing were determined. LEVEL OF CLINICAL EVIDENCE: 5.

L-Arginine Doped Carbon Nanodots from Cinnamon Bark for Improved Fluorescent Yeast Cell Imaging.

In this study, we present an economical and efficient synthesis method for carbon nanodots (CNDs) derived from cinnamon bark wood powder, with the incorporation of L-arginine as a dopant at varying ratios (Cinnamon : L-Arginine - 1:0.25, 1:0.5) via a hydrothermal reaction. Extensive structural and optical characterization was conducted through techniques such as FTIR, XRD, HR-TEM, DLS, UV-Vis, and PL spectra, providing a comprehensive understanding of the properties of CNDs and doped-CNDs. Quantum yields (QY) were quantified for synthesized materials, contributing to the assessment of their fluorescence efficiency. The synthesized CNDs were successfully applied for bioimaging of yeast cells, employing fluorescence microscopy to visualize their interaction. Remarkably, L-arginine-doped CNDs exhibited enhanced fluorescence, showcasing the influence of the dopant. The nature of these CNDs was rigorously investigated, confirming their biocompatibility. Notably, this work presents a novel approach to synthesizing CNDs from a renewable and sustainable source, cinnamon bark wood powder, while exploring the effects of L-arginine doping on their optical and biological properties. This work not only contributes to the synthesis and characterization of CNDs but also highlights their potential for diverse applications, emphasizing their structural, optical, and biological attributes. The findings underscore the versatility of CNDs derived from cinnamon bark wood powder and their potential for advancing biotechnological and imaging applications.

Sitagliptin ameliorates L-arginine-induced acute pancreatitis via modulating inflammatory cytokines expression and combating oxidative stress.

Background: Acute pancreatitis (AP) is an inflammatory condition that resolves spontaneously, but occasionally, develops into systemic inflammation, organ failure and mortality. Oxidative stress and activation of inflammatory pathways represent major players in AP pathogenesis. Current management of AP relies on attenuating injuries to the pancreas and putting the inflammatory process under control. In this study, we investigated the role of sitagliptin in modulating L-arginine-induced AP in rats. Methods: Swiss rats were subdivided into a healthy control group, AP group (a single dose of L-arginine 250 mg/100 g, intraperitoneal), and sitagliptin + L-arginine-treated group (10 mg sitagliptin/kg body weight/day, orally). Sitagliptin treatment started 1 hour after L-arginine injection and continued for 3days. Biochemical and histopathological investigations were performed on serum and tissue samples collected from test animals. Results: L-arginine increased pancreatic meyloperoxidase and serum amylase- and lipase activities and serum levels of TNF-α, LT-α, IFN-γ, IL-1α/ß, IL-6, IL-10, IL-12, and IL-15. AP animals showed elevated MDA and NO and decreased GSH and serum calcium levels. Histopathological changes were observed by H&E staining. Sitagliptin treatment significantly ameliorated these biochemical and histological changes diminishing the signs of AP. Conclusion: Sitagliptin treatment was effective in ameliorating L-arginine-induced AP which can be regarded to its anti-inflammatory and antioxidant effect.

L-Arginine-induced acute pancreatitis and its associated lung injury in rats: Down-regulation of TLR-4/MAPK-p38/JNK signaling pathway via Ginkgo biloba extract EGb 761.

Objectives: Acute pancreatitis (AP) is an abrupt inflammatory condition characterized by a storm of inflammatory cytokines leading to high morbidity and mortality. The current study aimed to examine the efficacy of Ginkgo biloba extract EGb 761 (GBE) in the treatment of L-arginine-induced AP and its associated lung injury. Materials and Methods: Forty rats were randomly assigned into four groups. The normal group received only saline intraperitoneally while the other groups received two intraperitoneal L-arginine injections (250 mg/100 g b.wt) separated by a 1-hour interval to provoke AP. GBE (200 and 400 mg/kg/day, PO) was administered for 2 weeks post-induction of pancreatitis. Sera and pancreatic tissues were isolated. Results: The outcome of the present study revealed that GBE ameliorated the elevated levels of serum amylase, lipase, and pancreatic inflammatory mediators viz., tumor necrosis factor-alpha (TNF-α), mitogen-activated protein kinase P38 (MAPK-P38), c-Jun N-terminal kinase 1 (JNK1), and nuclear factor-kappa B (NF-κB). Moreover, GBE restored the pancreatic gene expression of Toll-like receptor 4 (TLR4) and prostatic acid phosphatase-2 (PAP-2). Pancreatic and lung histopathological examinations confirmed the aforementioned parameters. Conclusion: GBE interfered with the mechanistic pathway of L-arginine-induced acute pancreatic and its associated lung injury. Due to its anti-inflammatory properties, GBE can be used as a novel therapeutic candidate for the treatment of AP through down-regulating TLR-4/MAPK-p38/JNK and MAPK- p38/NF-κB signaling cascades.

Therapeutic Modulation of Arginase with nor-NOHA Alters Immune Responses in Experimental Mouse Models of Pulmonary Tuberculosis including in the Setting of Human Immunodeficiency Virus (HIV) Co-Infection.

L-arginine metabolism is strongly linked with immunity to mycobacteria, primarily through the antimicrobial activity of nitric oxide (NO). The potential to modulate tuberculosis (TB) outcomes through interventions that target L-arginine pathways are limited by an incomplete understanding of mechanisms and inadequate in vivo modeling. These gaps in knowledge are compounded for HIV and Mtb co-infections, where activation of arginase-1 due to HIV infection may promote survival and replication of both Mtb and HIV. We utilized in vitro and in vivo systems to determine how arginase inhibition using Nω-hydroxy-nor-L-arginine (nor-NOHA) alters L-arginine pathway metabolism relative to immune responses and disease outcomes following Mtb infection. Treatment with nor-NOHA polarized murine macrophages (RAW 264.7) towards M1 phenotype, increased NO, and reduced Mtb in RAW macrophages. In Balb/c mice, nor-NOHA reduced pulmonary arginase and increased the antimicrobial metabolite spermine in association with a trend towards reduced Mtb CFU in lung. In humanized immune system (HIS) mice, HIV infection increased plasma arginase and heightened the pulmonary arginase response to Mtb. Treatment with nor-NOHA increased cytokine responses to Mtb and Mtb/HIV in lung tissue but did not significantly alter bacterial burden or viral load. Our results suggest that L-arginine pathway modulators may have potential as host-directed therapies to augment antibiotics in TB chemotherapy.

Mitochondria-engine with self-regulation to restore degenerated intervertebral disc cells via bioenergetic robust hydrogel design.

Previous studies have confirmed that intervertebral disc degeneration (IDD) is closely associated with inflammation-induced reactive oxygen species (ROS) and resultant cell mitochondrial membrane potential (MMP) decline. Clearance of ROS in an inflammatory environment is essential for breaking the vicious cycle of MMP decline. Additionally, re-energizing the mitochondria damaged in the inflammatory milieu to restore their function, is equally important. Herein, we proposed an interesting concept of mitochondrion-engine equipped with coolant, which enables first to "cool-down" the inflammatory environment, next to restore the MMP, finally to allow cells to regain normal energy metabolism through materials design. As such, we developed a multi-functional composite composed of a reactive oxygen species (ROS)-responsive sodium alginate/gelatin hydrogel infused into a rigid 3D-printed thermoplastic polyurethane (TPU) scaffold. The TPU scaffold was coated with conductive polypyrrole (PPy) to electrophoretically deposit l-arginine, which could upregulate the Mammalian target of rapamycin (mTOR) pathway, thus increasing MMP and energy metabolism to stimulate extracellular matrix synthesis for IVD repair. While the ROS-responsive hydrogel acting as the "mito-engine coolant" could scavenge the excessive ROS to create a favorable environment for IVD cells recovery. Demonstrated by in vitro and in vivo evaluations, the mito-engine system markedly promoted the proliferation and collagen synthesis of nucleus pulposus cells while enhancing the mitochondrial respiration and MMP under oxidative stress. Radiological and histological assessments in vivo revealed the efficacy of this system in IVD repair. This unique bioinspired design integrated biomaterial science with mitochondrial biology, presents a promising paradigm for IDD treatment.

L-arginine combination with 5-fluorouracil inhibit hepatocellular carcinoma cells through suppressing iNOS/NO/AKT-mediated glycolysis.

L-arginine can produce nitric oxide (NO) under the action of inducible nitric oxide synthase (iNOS), while 5-fluorouracil (5-FU) can induce the increase of iNOS expression. The present study was to investigate the mechanism of L-arginine combined with 5-FU regulating glucose metabolism of hepatocellular carcinoma (HCC) through iNOS/NO/AKT pathway. The combination of L-arginine and 5-FU resulted in decreased cell survival and exhibited synergistic cytotoxic effects in HepG2 and SMMC7721 cells. Meanwhile, L-arginine increased 5-FU inhibitory effect on HepG2 and SMMC7721 cells by increasing NO production. Co-treatment with L-arginine and 5-FU resulted in a significant decrease in both G6PDH and LDH enzymatic activities, as well as reduced levels of ATP and LD compared to treatment with L-arginine or 5-FU alone. Moreover, the combination of L-arginine and 5-FU resulted in a decrease in the expression of GLUT1, PKM2, LDHA, p-PI3K and p-AKT. Furthermore, the combination demonstrated a synergistic effect in downregulating the expression of HIF-1α and ß-catenin, which were further diminished upon the addition of shikonin, a specific inhibitor of PKM2. LY294002 treatment further reduced the expression of GLUT1, PKM2, and LDHA proteins induced by combined L-arginine and 5-FU treatment compared to the combined group. However, the reduction in p-PI3K, p-AKT, and GLUT1 expression caused by L-arginine and 5-FU combination was also reversed in HepG2 and SMMC7721 cells with iNOS knockdown, respectively. Additionally, the combination of L-arginine and 5-FU led to a greater reduction in the enzymatic activity of ALT, AST, G6PDH and LDH, as well as a significant reduction in hepatic index, AFP, AFP-L3, ATP and LD levels in a rat model of HCC. Moreover, the simultaneous administration of L-arginine and 5-FU significantly improved the gross morphology of the liver, reduced nuclear atypia, inhibited the proliferation of cancer cells, and decreased the expression levels of p-PI3K, p-AKT, GLUT1, PKM2, and LDHA, while iNOS expression was increased in the combination group. Taking together, L-arginine and 5-FU combination resulted in the inhibition of enzymes in aerobic glycolysis via the iNOS/NO/AKT pathway, which led to the suppression of glucose metabolism and downregulation of nuclear transcription factors, thereby impeding the proliferation of hepatocellular carcinoma cells.

Products of oxidative and non-oxidative metabolism of L-arginine as potential regulators of Ca2+ transport in mitochondria of uterine smooth muscle.

Mitochondria play a crucial role in maintaining Ca2+ homeostasis in cells. Due to the critical regulatory role of the products of oxidative and non-oxidative metabolism of L-arginine, it is essential to clarify their effect on Ca2+ transport in smooth muscle mitochondria. Experiments were performed on the uterine myocytes of rats and isolated mitochondria. The possibility of NO synthesis by mitochondria was demonstrated by confocal microscopy and spectrofluorimetry methods using the NO-sensitive fluorescent probe DAF-FM and Mitotracker Orange CM-H2TMRos. It was shown that 50 µM L-arginine stimulates the energy-dependent accumulation of Ca2+ in mitochondria using the fluorescent probe Fluo-4 AM. A similar effect occurred when using nitric oxide donors 100 µM SNP, SNAP, and sodium nitrite (SN) directly. The stimulating effect was eliminated in the presence of the NO scavenger C-PTIO. Nitric oxide reduces the electrical potential in mitochondria without causing them to swell. The stimulatory effect of spermine on the accumulation of Ca2+ by mitochondria is attributed to the enhancement of NO synthesis, which was demonstrated with the use of C-PTIO, NO-synthase inhibitors (100 µM NA and L-NAME), as well as by direct monitoring of NO synthesis fluorescent probe DAF-FM. A conclusion was drawn about the potential regulatory effect of the product of the oxidative metabolism of L-arginine - NO on the transport of Ca2+ in the mitochondria of the myometrium, as well as the corresponding effect of the product of non-oxidative metabolism -spermine by increasing the synthesis of NO in these subcellular structures.

M1 Macrophage-Targeted Curcumin Nanocrystals with l-Arginine-Modified for Acute Lung Injury by Inhalation.

Acute Lung Injury/Acute Respiratory Distress Syndrome (ALI/ARDS) with clinical manifestations of respiratory distress and hypoxemia remains a significant cause of respiratory failure, boasting a persistently high incidence and mortality rate. Given the central role of M1 macrophages in the pathogenesis of acute lung injury (ALI), this study utilized the anti-inflammatory agent curcumin as a model drug. l-arginine (L-Arg) was employed as a targeting ligand, and chitosan was initially modified with l-arginine. Subsequently, it was utilized as a surface modifier to prepare inhalable nano-crystals loaded with curcumin (Arg-CS-Cur), aiming for specific targeting of pulmonary M1 macrophages. Compared with unmodified chitosan-curcumin nanocrystals (CS-Cur), Arg-CS-Cur exhibited higher uptake in vitro by M1 macrophages, as evidenced by flow cytometry showing the highest fluorescence intensity in the Arg-CS-Cur group (P < 0.01). In vivo accumulation was greater in inflamed lung tissues, as indicated by small animal imaging demonstrating higher lung fluorescence intensity in the DiR-Arg-CS-Cur group compared to the DiR-CS-Cur group in the rat ALI model (P < 0.05), peaking at 12 h. Moreover, Arg-CS-Cur demonstrated enhanced therapeutic effects in both LPS-induced RAW264.7 cells and ALI rat models. Specifically, treatment with Arg-CS-Cur significantly suppressed NO release and levels of TNF-α and IL-6 in RAW264.7 cells (p < 0.01), while in ALI rat models, expression levels of TNF-α and IL-6 in lung tissues were significantly lower than those in the model group (P < 0.01). Furthermore, lung tissue damage was significantly reduced, with histological scores significantly lower than those in the CS-Cur group (P < 0.01). In conclusion, these findings underscore the targeting potential of l-arginine-modified nanocrystals, which effectively enhance curcumin concentration in inflammatory environments by selectively targeting M1 macrophages. This study thus introduces novel perspectives and theoretical support for the development of targeted therapeutic interventions for acute inflammatory lung diseases, including ALI/ARDS.