PEGylation renders carnosine resistant to hydrolysis by serum carnosinase and increases renal carnosine levels.

Carnosine's protective effect in rodent models of glycoxidative stress have provided a rational for translation of these findings in therapeutic concepts in patient with diabetic kidney disease. In contrast to rodents however, carnosine is rapidly degraded by the carnosinase-1 enzyme. To overcome this hurdle, we sought to protect hydrolysis of carnosine by conjugation to Methoxypolyethylene glycol amine (mPEG-NH2). PEGylated carnosine (PEG-car) was used to study the hydrolysis of carnosine by human serum as well as to compare the pharmacokinetics of PEG-car and L-carnosine in mice after intravenous (IV) injection. While L-carnosine was rapidly hydrolyzed in human serum, PEG-car was highly resistant to hydrolysis. Addition of unconjugated PEG to carnosine or PEG-car did not influence hydrolysis of carnosine in serum. In mice PEG-car and L-carnosine exhibited similar pharmacokinetics in serum but differed in half-life time (t1/2) in kidney, with PEG-car showing a significantly higher t1/2 compared to L-carnosine. Hence, PEGylation of carnosine is an effective approach to prevent carnosine degradations and to achieve higher renal carnosine levels. However, further studies are warranted to test if the protective properties of carnosine are preserved after PEGylation.

Serum carnosinase 1, an early indicator for incident microalbuminuria in type 1 diabetes.

Aims: Carnosinase (CN1) polymorphisms have been linked to diabetic kidney disease (DKD), as CN1 degrades dipeptides which scavenge oxidative metabolites and prevent the formation of advanced glycation end-products. In this work, we studied the association between serum CN1, the systemic redox status and long-term renal outcome in type 1 diabetes. Methods: Serum CN1 was measured in a prospective type 1 diabetes cohort (n = 218) with a 16-year follow-up. A total of 218 patients treated at the Diabetes Outpatient Clinic of the Weezenlanden Hospital (nowadays Isala Hospital, Zwolle, The Netherlands) were included in this analysis. We assessed whether serum CN1 was associated with renal function and development of DKD as well as other diabetic complications. Results: At baseline, age, systemic redox status and N-terminal pro brain-natriuretic peptide (NT-proBNP) were associated with serum CN1 concentration (p < 0.05). During follow-up, CN1 concentration in the middle tertile was associated with less incident microalbuminuria (odds ratio = 0.194, 95% C.I.: 0.049-0.772, p = 0.02) after adjustment for age, systemic redox status, NT-proBNP and sex. Discussion: Serum CN1 could predict incident microalbuminuria and may be used as a novel parameter to identify patients at risk for DKD.

Determination of Imidazole Dipeptides and Related Amino Acids in Natural Seafoods by Liquid Chromatography-Tandem Mass Spectrometry Using a Pre-Column Derivatization Reagent.

Imidazole dipeptides (IDPs) and taurine (Tau) have several health benefits and are known to be contained in natural seafoods. However, their levels vary widely in different natural seafoods, making their simultaneous determination desirable. Herein, we employ a liquid chromatography-tandem mass spectrometry approach using a novel amino group derivatization reagent, succinimidyl 2-(3-((benzyloxy)carbonyl)-1-methyl-5-oxoimidazolidin-4-yl) acetate ((R)-CIMa-OSu), for the simultaneous quantification of IDPs (carnosine (Car) and anserine (Ans)), their related amino acids, and Tau in natural seafoods. Each seafood sample contained different concentrations of IDPs (Car: ND to 1.48 mmol/100 g-wet, Ans: ND to 4.67 mmol/100 g-wet). The Car levels were considerably higher in eel, while Tau was more abundant in squid, boiled octopus, and scallop. Thus, the derivatization reagent (R)-CIMa-OSu provides a new approach to accurately assess the nutritional composition of seafoods, thereby providing valuable insight into its dietary benefits.

The Role of Zinc in the Development of Vascular Dementia and Parkinson's Disease and the Potential of Carnosine as Their Therapeutic Agent.

Synaptic zinc ions (Zn2+) play an important role in the development of vascular dementia (VD) and Parkinson's disease (PD). In this article, we reviewed the current comprehension of the Zn2+-induced neurotoxicity that leads to the pathogenesis of these neuronal diseases. Zn2+-induced neurotoxicity was investigated by using immortalised hypothalamic neurons (GT1-7 cells). This cell line is useful for the development of a rapid and convenient screening system for investigating Zn2+-induced neurotoxicity. GT1-7 cells were also used to search for substances that prevent Zn2+-induced neurotoxicity. Among the tested substances was a protective substance in the extract of Japanese eel (Anguilla japonica), and we determined its structure to be like carnosine (ß-alanylhistidine). Carnosine may be a therapeutic drug for VD and PD. Furthermore, we reviewed the molecular mechanisms that involve the role of carnosine as an endogenous protector and its protective effect against Zn2+-induced cytotoxicity and discussed the prospects for the future therapeutic applications of this dipeptide for neurodegenerative diseases and dementia.

Mini-encyclopedia of mitochondria-relevant nutraceuticals protecting health in primary and secondary care-clinically relevant 3PM innovation.

Despite their subordination in humans, to a great extent, mitochondria maintain their independent status but tightly cooperate with the "host" on protecting the joint life quality and minimizing health risks. Under oxidative stress conditions, healthy mitochondria promptly increase mitophagy level to remove damaged "fellows" rejuvenating the mitochondrial population and sending fragments of mtDNA as SOS signals to all systems in the human body. As long as metabolic pathways are under systemic control and well-concerted together, adaptive mechanisms become triggered increasing systemic protection, activating antioxidant defense and repair machinery. Contextually, all attributes of mitochondrial patho-/physiology are instrumental for predictive medical approach and cost-effective treatments tailored to individualized patient profiles in primary (to protect vulnerable individuals again the health-to-disease transition) and secondary (to protect affected individuals again disease progression) care. Nutraceuticals are naturally occurring bioactive compounds demonstrating health-promoting, illness-preventing, and other health-related benefits. Keeping in mind health-promoting properties of nutraceuticals along with their great therapeutic potential and safety profile, there is a permanently growing demand on the application of mitochondria-relevant nutraceuticals. Application of nutraceuticals is beneficial only if meeting needs at individual level. Therefore, health risk assessment and creation of individualized patient profiles are of pivotal importance followed by adapted nutraceutical sets meeting individual needs. Based on the scientific evidence available for mitochondria-relevant nutraceuticals, this article presents examples of frequent medical conditions, which require protective measures targeted on mitochondria as a holistic approach following advanced concepts of predictive, preventive, and personalized medicine (PPPM/3PM) in primary and secondary care.

The protective role of carnosine against type 2 diabetes-induced cognitive impairment.

The morbidity and mortality associated with type 2 diabetes mellitus (T2DM) have grown exponentially over the last 30 years. Together with its associated complications, the mortality rates have increased. One important complication in those living with T2DM is the acceleration of age-related cognitive decline. T2DM-induced cognitive impairment seriously affects memory, executive function, and quality of life. However, there is a lack of effective treatment for both diabetes and cognitive decline. Thus, finding novel treatments which are cheap, effective in both diabetes and cognitive impairment, are easily accessible, are needed to reduce impact on patients with diabetes and health-care systems. Carnosine, a histidine containing dipeptide, plays a protective role in cognitive diseases due to its antioxidant, anti-inflammation, and anti-glycation properties, all of which may slow the development of neurodegenerative diseases and ischemic injury. Furthermore, carnosine is also involved in regulating glucose and insulin in diabetes. Herein, we discuss the neuroprotective role of carnosine and its mechanisms in T2DM-induced cognitive impairment, which may provide a theoretical basis and evidence base to evaluate whether carnosine has therapeutic effects in alleviating cognitive dysfunction in T2DM patients.

The Potential of Chicken-Herb Essence to Improve Milk Production and Infant Health in the Sprague Dawley Animal Model.

Breast milk serves as the primary source of nourishment for newborns. In cases of low milk production, one approach to address this challenge involves the consumption of lactagogues. Chicken-herb essence, a beverage rich in protein, amino acids, and minerals, presents itself as a viable option to supplement a lactating mother's diet, particularly in terms of protein intake. This study aimed to evaluate the effects of chicken-herb essence on prolactin and lactoferrin in lactating rats. Furthermore, the study also assessed the lactagogue effect on IgA in offspring. The experimental research method used a completely randomized design. The animal models in this study were female Sprague Dawley rats. The result showed that there was an increase in milk production, as seen from the results of the lactagogue effect. The highest increase in prolactin and lactoferrin was obtained in treatment group II (TG II). The increases in prolactin and lactoferrin of TG II were 214.18 ± 71.99 and 904.02 ± 435.35 pg/mL, respectively. The lactagogue test showed that TG II haspotency as a milk-booster. Testing the blood serum of offspring showed that the highest concentration of IgA was also found in TG II at 398.34 ± 214.85 pg/mL.

Comprehensive pan-cancer investigation of carnosine dipeptidase 1 and its prospective prognostic significance in hepatocellular carcinoma.

Carnosine dipeptidase 1 (CNDP1), an enzyme integral to the hydrolysis of dipeptides containing histidine, plays an indispensable role in myriad physiological processes, including hydrolysis of proteins, maturation of specific biochemical functionalities within proteins, tissue regeneration, and regulation of cell cycle. However, the implications of CNDP1 in oncogenesis and its prognostic value are not yet fully elucidated. Initially, we procured the GSE40367 dataset from the Gene Expression Omnibus and established a protein-protein interaction network. Thereafter, we conducted functional and pathway enrichment analyses utilizing GO, KEGG, and GSEA. Moreover, we undertook an association analysis concerning the expression of CNDP1 with immune infiltration, along with survival analysis across various cancers and specifically in hepatocellular carcinoma (HCC). Our study uncovered a total of 2,248 differentially expressed genes, with a down-regulation of CNDP1 in HCC and other cancers. Our explorations into the relationship between CNDP1 and immune infiltration disclosed a negative correlation between CNDP1 expression and the presence of immune cells in HCC. Survival analyses revealed that diminished expression of CNDP1 correlates with an adverse prognosis in HCC and several other types of cancer. These observations intimate that CNDP1 holds promise as a novel prognostic biomarker for both pan-cancer and HCC.

State of the Art in the Development of Human Serum Carnosinase Inhibitors.

Human serum carnosinase is an enzyme that operates the preferential hydrolysis of dipeptides with a C-terminus histidine. Only higher primates excrete such an enzyme in serum and cerebrospinal fluid. In humans, the serum hydrolytic rate has high interindividual variability owing to gene polymorphism, although age, gender, diet, and also diseases and surgical interventions can modify serum activity. Human genetic diseases with altered carnosinase activity have been identified and associated with neurological disorders and age-related cognitive decline. On the contrary, low peripheral carnosinase activity has been associated with kidney protection, especially in diabetic nephropathy. Therefore, serum carnosinase is a druggable target for the development of selective inhibitors. However, only one molecule (i.e., carnostatine) has been discovered with the purpose of developing serum carnosinase inhibitors. Bestatin is the only inhibitor reported other than carnostatine, although its activity is not selective towards serum carnosinase. Herein, we present a review of the most critical findings on human serum carnosinase, including enzyme expression, localization and substrate selectivity, along with factors affecting the hydrolytic activity, its implication in human diseases and the properties of known inhibitors of the enzyme.

The effect of gut microbiota-derived carnosine on mucosal integrity and immunity in broiler chickens challenged with Eimeria maxima.

In the first study, an in vitro culture system was developed to investigate the effects of carnosine on macrophage proinflammatory cytokine response using an established chicken macrophage cell line (CMC), gut integrity using a chicken intestinal epithelial cell line (IEC), muscle differentiation in quail muscle cells (QMCs) and primary chicken embryonic muscle cells (PMCs), and direct anti-parasitic effect against Eimeria maxima sporozoites. Cells to be tested were seeded in 24-well plates and treated with carnosine at 4 different concentrations (0.1, 1.0, and 10.0 µg). After 18 h of incubation, cells were harvested to measure gene expression of proinflammatory cytokines in CMC, tight junction (TJ) proteins in IECs, and muscle cell growth markers in QMCs and PMCs. In vivo trials were conducted to investigate the effect of dietary carnosine on disease parameters in broiler chickens challenged with E. maxima. One hundred and twenty male broiler chickens (0-day-old) were allocated into 4 treatment groups: 1) basal diet without infection (NC), 2) basal diet with E. maxima infection (PC), 3) carnosine at 10.0 mg/kg feed with PC (HCS), and 4) carnosine at 1.0 mg/kg feed with PC (LCS). All groups except NC were orally infected with E. maxima on d 14. Jejunal samples were collected for lesion scoring and jejunum gut tissues were used for transcriptomic analysis of cytokines and TJ proteins. In vitro, carnosine treatment significantly decreased IL-1ß gene expression in CMC following LPS stimulation. In vivo feeding studies showed that dietary carnosine increased BW and ADG of chickens in E. maxima-infected groups and reduced the jejunal lesion score and fecal oocyst shedding in HCS group. Jejunal IL-1ß, IL-8, and IFN-γ expression were suppressed in the HCS group compared to PC. The expression levels of claudin-1 and occludin in IECs were also increased in HCS following carnosine treatment. In conclusion, these findings highlight the beneficial effects of dietary carnosine supplementation on intestinal immune responses and gut barrier function in broiler chickens exposed to E. maxima infection.

Muscle-Protective Effect of Carnosine against Dexamethasone-Induced Muscle Atrophy in C2C12 Myotube.

This study investigated the protective effect of carnosine and its components (L-histidine and ß-alanine [HA]) against dexamethasone (Dex)-induced muscle atrophy in C2C12 myotubes. Myotubes were treated with Dex (10 µM) to induce muscle atrophy manifested by decreased myotube diameter, low myosin heavy chain content, and increased expression of muscle atrophy-associated ubiquitin ligases (Atrogin-1, MuRF-1, and Cbl-b). Carnosine (20 mM) treatment significantly improved the myotube diameter and MyHC protein expression level in Dex-treated C2C12 myotubes. It also downregulated the expression of Atrogin-1, MuRF-1, and Cbl-b and suppressed the expression of forkhead box O3 (FoxO3a) mediated by Dex. Furthermore, reactive oxygen species production was increased by Dex but was ameliorated by carnosine treatment. However, HA (20 mM), the component of carnosine, treatment was found ineffective in preventing Dex-induced protein damage. Therefore, based on above results it can be suggested that carnosine could be a potential therapeutic agent to prevent Dex-induced muscle atrophy compared to its components HA.

Identification and structure-based engineering of a dipeptidase CpPepD from Clostridium perfringens for the synthesis of l-carnosine.

l-Carnosine (l-Car), an endogenous dipeptide presents in muscle and brain tissues of various vertebrates, has a wide range of application values. The enzymatic preparation of l-Car is a promising synthetic method because it avoids the protection and deprotection steps. In the present study, a dipeptidase gene (CpPepD) from Clostridium perfringens with high l-Car synthetic activity was cloned and characterized. In an effort to improve the performance of this enzyme, we carried out site saturation mutagenesis using CpPepD as the template. By the o-phthalaldehyde (OPA)-derived high throughput screening method, mutant A171S was obtained with 2.2-fold enhanced synthetic activity. The enzymatic properties of CpPepD and mutant A171S were investigated. Under the optimized conditions, 63.94 mM (14.46 g L-1) or 67.02 mM (15.16 g L-1) l-Car was produced at the substrate concentrations of 6 M ß-Ala and 0.2 M l-His using wild-type or mutant A171S enzyme, respectively. Although the mutation enhanced the enzyme activity, the reaction equilibrium was barely affected.

Metabolomic profiles of preterm small-for-gestational age infants.

We aimed to characterize the metabolomic profiles in preterm small-for-gestational age (SGA) infants using cord blood. We conducted a gestational age (GA)-matched case-control study that included 30 preterm infants who were categorized into two groups: SGA infants, with a birth weight (BW) < 10th percentile for GA (n = 15) and non-SGA infants, with BW ≥ 10th percentile for GA (n = 15). SGA infants with chromosomal or genetic abnormalities were excluded. At birth, the umbilicus was double-clamped, and the cord blood was sampled from the umbilical vein. Metabolomic analyses were performed using capillary electrophoresis time-of-flight mass spectrometry. The median GA at birth was not significantly different between the two groups [SGA, 32 (26-36) weeks; non-SGA, 32 (25-35) weeks; p = 0.661)]. Of the 255 metabolites analyzed, 19 (7.5%) showed significant differences between SGA and non-SGA infants. There were significant reductions in the carnosine, hypotaurine, and S-methylcysteine levels in SGA infants as compared to non-SGA infants (p < 0.05). Carnosine was correlated with gestational age, BMI before pregnancy, body weight gain during pregnancy (p = 0.002, p = 0.023, and p = 0.020, respectively). In conclusion, preterm SGA infants have low levels of cord blood antioxidative- and antiglycation-related metabolites, making them vulnerable to oxidative stress.

A Patented Dietary Supplement (Hydroxy-Methyl-Butyrate, Carnosine, Magnesium, Butyrate, Lactoferrin) Is a Promising Therapeutic Target for Age-Related Sarcopenia through the Regulation of Gut Permeability: A Randomized Controlled Trial.

Adequate diet, physical activity, and dietary supplementation with muscle-targeted food for special medical purposes (FSMP) or dietary supplement (DS) are currently considered fundamental pillars in sarcopenia treatment. The aim of this study is to evaluate the effectiveness of a DS (containing hydroxy-methyl-butyrate, carnosine, and magnesium, for its action on muscle function and protein synthesis and butyrate and lactoferrin for their contribution to the regulation of gut permeability and antioxidant/anti-inflammation activity) on muscle mass (assessed by dual X-ray absorptiometry (DXA)), muscle function (by handgrip test, chair test, short physical performance battery (SPPB) test, and walking speed test), inflammation (tumor necrosis factor-alpha (TNF-a), C-reactive protein (CRP), and visceral adipose tissue (VAT)) and gut axis (by zonulin). A total of 59 participants (age 79.7 ± 4.8 years, body mass index 20.99 ± 2.12 kg/m2) were enrolled and randomly assigned to intervention (n = 30) or placebo (n = 28). The skeletal muscle index (SMI) significantly improved in the supplemented group compared to the placebo one, +1.02 (CI 95%: -0.77; 1.26), p = 0.001; a significant reduction in VAT was observed in the intervention group, -70.91 g (-13.13; -4.70), p = 0.036. Regarding muscle function, all the tests significantly improved (p = 0.001) in the supplemented group compared to the placebo one. CRP, zonulin, and TNF-alpha significantly decreased (p = 0.001) in intervention, compared to placebo, -0.74 mg/dL (CI 95%: -1.30; -0.18), -0.30 ng/mL (CI 95%: -0.37; -0.23), -6.45 pg/mL (CI 95%: -8.71; -4.18), respectively. This DS improves muscle mass and function, and the gut muscle has emerged as a new intervention target for sarcopenia.

Carnosine ameliorates postoperative cognitive dysfunction of aged rats by limiting astrocytes pyroptosis.

Postoperative cognitive dysfunction (POCD) is a common postoperative complication in elderly patients, and neuroinflammation is a key hallmark. Recent studies suggest that the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome-mediated astrocytes pyroptosis is involved in the regulation of neuroinflammation in many neurocognitive diseases, while its role in POCD remains obscure. Carnosine is a natural endogenous dipeptide with anti-inflammatory and neuroprotective effects. To explore the effect of carnosine on POCD and its mechanism, we established a POCD model by exploratory laparotomy in 24-month-old male Sprague-Dawley rats. We found that the administrated of carnosine notably attenuated surgery-induced NLRP3 inflammasome activation and pyroptosis in astrocytes, central inflammation, and neuronal damage in the hippocampus of aged rats. In addition, carnosine dramatically ameliorated the learning and memory deficits of surgery-induced aged rats. Then in the in vitro experiments, we stimulated primary astrocytes with lipopolysaccharide (LPS) after carnosine pretreatment. The results also showed that the application of carnosine alleviated the activation of the NLRP3 inflammasome, pyroptosis, and inflammatory response in astrocytes stimulated by LPS. Taken together, these findings suggest that carnosine improves POCD in aged rats via inhibiting NLRP3-mediated astrocytes pyroptosis and neuroinflammation.

Association of HNMT gene polymorphisms with carnosine content in red-brown Korean native chickens.

Objective: Carnosine and anserine affect the meat flavor. The contents of carnosine and anserine in meat are affected by genetic and environmental factors. This study aimed to discover the single-nucleotide polymorphisms (SNPs) in the HNMT and HNMT-like genes and to associate them with the content of carnosine and anserine in Korean native chicken-red brown line (KNC-R ). Methods: This study used a total of 384 birds (males, n=192; females, n=192) aged 10 weeks old, for genotyping HNMT and HNMT-like genes. One synonymous SNP (rs29009298C/T) of the HNMT gene was genotyped by PCR-RFLP methods whereas four missense SNPs (rs734406537G/A; rs736514667A/G; rs15881680G/A and rs316765035T/C) of the HNMT gene, and one missense SNP rs737657949A/C of the HNMT-like gene were genotyped by PACE genotyping technology. Two-way ANOVA of the R program was used to associate HNMT genotypes with the contents of carnosine and anserine in KNC- R chickens. Results: There were significant associations (p<0.05) between the genotypes of the synonymous SNP:rs29009298C/T, missense SNP rs736514667A/G of the HNMT gene and the content of carnosine in KNC-Rs. This study also reported the sex effect on the carnosine content, where females had more content of carnosine compared to that of male KNC-R. Conclusion: Two SNPs (synonymous: rs735769522C/T) and missense: rs736514667A/G) in the HNMT gene might be used as genetic markers in the selection and breeding of chickens with better taste and high-flavored meat.

Effect of ß-alanine on the athletic performance and blood amino acid metabolism of speed-racing Yili horses.

The objective of this study was to examine the effects of supplemental ß-alanine feeding on the athletic performance of Yili horses involved in speed racing, focusing on alterations in plasma free amino acid patterns pre and post exercise. Additionally, the research aimed to evaluate the effects of carnosine on the plasma acid-base buffering capacity and antioxidant levels in these horses. Twelve Yili horse stallions, averaging 3 years in age and 346.50 ± 21.39 kg in weight, were chosen and randomly divided into two groups: a control group and a test group, each comprising six horses. The control group received a supplementation of 300 mg/kg BW/day of α-alanine, while the test group received 300 mg/kg BW/day of ß-alanine. This supplementation regimen was maintained for a 30-day supplementation trial period, under identical feeding and management conditions. Throughout the trial, the horses participated in the 1,000 Speed Race, and three distinct blood samples were gathered for assessing plasma free amino acids, blood gases, biochemical parameters, and antioxidant parameters. The outcomes indicated a considerable enhancement in the 1,000 m exercise performance of the speed racing Yili horses in the test group compared to the control group, showcasing a noteworthy improvement of 12.01%, with the test group completing the race 13.29 s faster. Notably, the α-alanine content in the plasma of the control group Yili horses remained higher than that of the test group, demonstrating a consistent increasing trend. By contrast, the plasma ß-alanine content was notably higher in the test group than in the control group. Over the course of the supplementation period, plasma ß-alanine exhibited an escalating and then stabilizing trend in the test group, whereas in the control group, although ß-alanine content also increased, the trend was less pronounced. The plasma levels of histidine and carnosine showed minimal variance between the two groups. Overall, the test group of Yili horses exhibited slightly higher plasma levels of histidine and carnosine compared to the control group. The addition of ß-alanine to their diet for a duration of 30 days notably affected the plasma levels of amino acids both pre- and post-exercise in speed-racing Yili horses. Furthermore, ß-alanine demonstrated an inhibitory effect on the catabolism of these horses' bodies during high-intensity exercise. Ten marker amino acids, including valine, leucine, ß-alanine, isoleucine, carnosine, 3-methyl-histidine, lysine, ethanolamine, argnine, and taurine, displayed statistically significant changes. ß-alanine notably increased the blood glucose levels of Yili horses and played a role in expediting the restoration of blood gas levels post-exercise. Moreover, in the test group of Yili horses, the levels of superoxide dismutase, glutathione peroxidase, and total antioxidant capacity significantly increased both before and after the race, while the content of malondialdehyde, an oxidation product, exhibited an extremely significant decrease immediately after the race. These outcomes suggest that the addition of ß-alanine significantly augmented antioxidant levels during high-intensity exercise in Yili horses. Consequently, it reduced post-exercise injuries and accelerated the recovery process after exercise.

Magnetic Lipid-Based hybrid nanosystems: A combined stimuli- responsive nanocarriers for enriched chemotherapeutic potential of L-carnosine in induced breast Ehrlich ascites tumor model.

Magnetic Lipid-Based Hybrid Nanosystems (M-LCNPs) is a novel nanoplatform that can respond to magnetic stimulus and are designed for delivering L-carnosine (CN), a challenging dipeptide employed in the treatment of breast cancer. CN exhibits considerable water solubility and undergoes in-vivo degradation, hence restricting its application. Consequently, it is anticipated that the developed M-LCNPs will enhance the effectiveness of CN. To ensure the physical stability of MNPs, they were initially coated with a mixture of oleic acid and oleylamine before being included in pegylated liquid crystalline nanoparticles (PLCNPs). The proposed M-LCNPs exhibited promising in-vitro characteristics, notably a small particle size (143.5 nm ± 1.25) and a high zeta potential (-39.5 mV ± 1.54), together with superparamagnetic behavior. The in-vitro release profile exhibited a prolonged release pattern. The IC50 values of M-LCNPs were 1.57 and 1.59 times lower than these of the CN solution after 24 and 48 hours, respectively. Female BALB/C female mice with an induced breast cancer (Ehrlich Ascites tumor [EAT] model) were used to study the influence of an external magnetic field on the chemotherapeutic activity and toxicity of CN loaded in the developed M-LCNPs. Stimuli-responsive M-LCNPs exhibited no apparent systemic toxicity in addition to enhanced chemotherapeutic efficacy compared to nontargeted M-LCNPs and CN solution, as evidenced by a reduction of % tumor growth (11.7%), VEGF levels (22.95 pg/g tissue), and cyclin D1 levels (27.61 ng/g tissue), and an increase in caspase-3 level (28.9 ng/g tissue). Ultimately, the developed stimuli-responsive CN loaded M-LCNPs presented a promising nanoplatform for breast cancer therapy.

Generation and Characterization of Stable Small Colony Variants of USA300 Staphylococcus aureus in RAW 264.7 Murine Macrophages.

Intracellular survival and immune evasion are typical features of staphylococcal infections. USA300 is a major clone of methicillin-resistant S. aureus (MRSA), a community- and hospital-acquired pathogen capable of disseminating throughout the body and evading the immune system. Carnosine is an endogenous dipeptide characterized by antioxidant and anti-inflammatory properties acting on the peripheral (macrophages) and tissue-resident (microglia) immune system. In this work, RAW 264.7 murine macrophages were infected with the USA300 ATCC BAA-1556 S. aureus strain and treated with 20 mM carnosine and/or 32 mg/L erythromycin. Stable small colony variant (SCV) formation on blood agar medium was obtained after 48 h of combined treatment. Whole genome sequencing of the BAA-1556 strain and its stable derivative SCVs when combining Illumina and nanopore technologies revealed three single nucleotide differences, including a nonsense mutation in the shikimate kinase gene aroK. Gene expression analysis showed a significant up-regulation of the uhpt and sdrE genes in the stable SCVs compared with the wild-type, likely involved in adaptation to the intracellular milieu.