Acetyl-L-Carnitine Induces Autophagy to Promote Mouse Spermatogonia Cell Recovery after Heat Stress Damage

The obesity-autophagy-cancer axis: Mechanistic insights and therapeutic perspectives

Autophagy, a self-degradative process vital for cellular homeostasis, plays a significant role in adipose tissue metabolism and tumorigenesis. This review aims to elucidate the complex interplay between autophagy, obesity, and cancer development, with a specific emphasis on how obesity-driven changes affect the regulation of autophagy and subsequent implications for cancer risk. The burgeoning epidemic of obesity underscores the relevance of this research, particularly given the established links between obesity, autophagy, and various cancers. Our exploration delves into hormonal influence, notably INS (insulin) and LEP (leptin), on obesity and autophagy interactions. Further, we draw attention to the latest findings on molecular factors linking obesity to cancer, including hormonal changes, altered metabolism, and secretory autophagy. We posit that targeting autophagy modulation may offer a potent therapeutic approach for obesity-associated cancer, pointing to promising advancements in nanocarrier-based targeted therapies for autophagy modulation. However, we also recognize the challenges inherent to these approaches, particularly concerning their precision, control, and the dual roles autophagy can play in cancer. Future research directions include identifying novel biomarkers, refining targeted therapies, and harmonizing these approaches with precision medicine principles, thereby contributing to a more personalized, effective treatment paradigm for obesity-mediated cancer.

Effect of L-carnitine in Ameliorating Lipopolysaccharide-Induced Cardiomyocyte Injury via MAPK Signaling

The present study aimed to elucidate whether L-carnitine (LC) protected H9c2 cells and its underlying mechanisms. Cell counting kit-8 (CCK-8) assay was used to evaluate cell viability. Apoptosis, cell morphology, and lactate dehydrogenase (LDH) assessment were used to prove effects of lipopolysaccharide (LPS) and LC on H9c2 cells. RT-qPCR and western blot assays were hired to evaluate the mRNA and protein expression levels, respectively. ELISA assay was performed to determine the released protein levels. Reactive oxygen species (ROS) level was evaluated by immunofluorescence and flow cytometry. LC was revealed to protect H9c2 cells against LPS-induced injury as indicated by increased cell viability, reduced apoptosis ratio and LDH level. LC treatment also reduced BAX expression as well as up-regulated Bcl-2 expression under LPS treatment. Mechanically, LC reduced oxidative stress and ameliorated the mitochondrial injury through modulating extracellular signal-regulated kinase 1/2 and c-Jun N-terminal protein kinase c-Jun N-terminal protein kinase phosphorylation levels as indicated by decreased membrane potential, increased ATP production and mtDNA expression. We found that LC ameliorates LPS-induced cardiomyocyte injury by abrogating cell apoptosis ratio, ROS levels, as well as mitochondrial dysfunction via mitogen-activated protein kinase signaling. Our findings revealed a potential drug for sepsis or LPS-induced cardiomyocyte injury.

Pasteurella multocida causes liver injury in ducks by mediating inflammatory, apoptotic and autophagic pathways

Pasteurella multocida.(PM) infection is a major cause of avian cholera, but the pathogenesis of the disease is unknown. The purpose of this study was to further understand the host response to infection by using a duck model of PM, 20 female ducks were divided into two groups (n = 10). One group was infected with PM, while the other served as an uninfected control group. The ducks were observed after infection and samples were collected for testing. In this study, we report the mechanism of PM-induced inflammation to further mediate apoptosis and autophagic signaling pathways in liver cells. Our results demonstrated that PM infection initially induces hemorrhagic and necrotic lesions in the liver tissue of duck, promoting inflammasome assembly and release, triggering inflammation. The TLR4/NF-κB axis activated and interacted with multiple inflammation-related proteins, including TNF-α and IL-1β, which affected apoptosis and autophagy. Tumor necrosis factor induced hepatocyte apoptosis was implicated in a wide range of liver diseases; the release of TNF-α and activation with NF-κB further incite apoptotic pathways,such as Bax/BCL2/caspase to promote apoptotic genes APAF1, Bax, Caspase3, BCL-2, p53, and Cytc expression. Finally, PM-induced autophagy suppressed liver injury by promoting the Beclin-1, LC3B, p62, and mTOR. Thus, liver injury caused by PM via promoting autophagy was induced. In conclusion, we analyzed the liver injury of ducks infected with PM, and confirmed that inflammation appeared in the liver; this was followed by the intricate interplay between inflammation, apoptosis, and autophagy signaling pathways. The observed results provided a reference basis for studying pathogenic mechanisms of PM-host interactions.

The Role of Melatonin to Ameliorate Oxidative Stress in Sperm Cells

It is widely accepted that oxidative stress (OS) coming from a wide variety of causes has detrimental effects on male fertility. Antioxidants could have a significant role in the treatment of male infertility, and the current systematic review on the role of melatonin to ameliorate OS clearly shows that improvement of semen parameters follows melatonin supplementation. Although melatonin has considerable promise, further studies are needed to clarify its ability to preserve or restore semen quality under stress conditions in varied species. The present review examines the actions of melatonin via receptor subtypes and its function in the context of OS across male vertebrates.

A comparative study of acetyl-l-carnitine and caloric restriction impact on hippocampal autophagy, apoptosis, neurogenesis, and astroglial function in AlCl3-induced Alzheimer's in rats

Alzheimer's disease (AD) is a worldwide chronic progressive neurodegenerative disease. We aimed to investigate and compare the neuroprotective impact of acetyl-l-carnitine and caloric restriction (CR) on AlCl₃-induced AD to explore the pathogenesis and therapeutic strategies of AD. Sixty-seven adult male Wistar rats were allocated into Control, AlCl₃, AlCl₃-acetyl-l-carnitine, and AlCl₃-CR groups. Each of AlCl₃ and acetyl-l-carnitine were given by gavage in a daily dose of 100 mg/kg and CR was conducted by giving 70% of the daily average caloric intake of the control group. Rats were subjected to behavioral assessment using open field test, Y maze, novel object recognition test and passive avoidance test, biochemical assay of serum phosphorylated tau (pTau), hippocampal homogenate phosphorylated adenosine monophosphate-activated protein kinase, Beclin-1, Bcl-2-associated X protein, and B cell lymphoma 2 (Bcl2) as well as hippocampal Ki-67 and glial fibrillary acidic protein immunohistochemistry. AlCl₃-induced cognitive and behavioral deficits coincident with impaired autophagy and enhanced apoptosis associated with defective neurogenesis and defective astrocyte activation. Acetyl-l-carnitine and CR partially protect against AlCl₃-induced behavioral, cognitive, biochemical, and histological changes, with more ameliorative effect of acetyl-l-carnitine on hippocampal apoptotic markers, and more obvious behavioral and histological improvement with CR.

Regulation of proliferation, apoptosis, hormone secretion and gene expression by acetyl-L-carnitine in yak (Bos grunniens) granulosa cells

Supplementation with acetyl-l-carnitine (ALC) during in vitro maturation significantly improves the rates of oocyte cleavage and morula and blastocyst formation in sheep and buffalo; however, the mode of action of ALC in improving oocyte competence is not completely understood. Therefore, the aim of this study was to investigate the effects of ALC on proliferation, antioxidant properties, lipid droplet accumulation and steroid hormone secretion in yak (Bos grunniens) granulosa cells (GCs). Yak GCs were identified using FSHR immunofluorescence. The cells were treated with different concentrations of ALC, cell proliferation was detected by cell counting kit-8, and the optimal concentration and treatment time were determined for subsequent experiments. Then, reactive oxygen species (ROS) were detected by a DCFH-DA probe, and lipid droplet accumulation was observed by oil red O staining. Estradiol (E2) and progesterone (P4) in the medium were detected by ELISA, and the expression of genes related to cell proliferation, apoptosis, the cell cycle, antioxidants and steroid synthesis was determined by RT‒qPCR. The results showed that 1 mM ALC treatment for 48 h was the optimum treatment. It significantly increased cell viability (P < 0.05), significantly decreased the amount of ROS and lipid droplet content, and promoted P4 and E2 secretion (P < 0.05) of yak GCs. RT‒qPCR results verified that GCs treated with 1 mM ALC for 48 h significantly increased the expression of genes related to anti-apoptosis and the cell cycle (BCL-2, PCNA, CCND1 and CCNB1), antioxidants (CAT, SOD2 and GPX1), and E2 and P4 secretion (StAR, CYP19A1 and HSD3B1) (P < 0.05), but it significantly decreased the expression of apoptosis genes (BAX and P53) (P < 0.05). In conclusion, ALC increased the viability of yak GCs, reduced the amount of ROS and lipid droplets, increased P4 and E2 synthesis and affected the expression of related genes in yak GCs.

Interaction between apoptosis and autophagy in testicular function

Several processes including oxidative stress, apoptosis, inflammation and autophagy are related to testicular function. Recent studies indicate that a crosstalk between apoptosis and autophagy is essential in regulating testicular function. Autophagy and apoptosis communicate with each other in a complex way, allowing them to work for or against each other in testicular cell survival and death. Several xenobiotics especially endocrine-disrupting chemicals (EDCs) have caused reproductive toxicity because of their potential to modify the rate of autophagy and trigger apoptosis. Therefore, the purpose of the present review was to shed light on how autophagy and apoptosis interact together in the testis.

Responses of sperm mitochondria functionality in animals to thermal stress: The mitigating effects of dietary natural antioxidants

The reproductive consequences of global warming representing heat stress (HS) have been widely received more attention in the last decades. HS induced significant influence on the male reproductive cell, especially sperm functionally. Reduction in the sperm function induced by HS leads to failure of fertility potential. The main effects of HS on sperm are reducing sperm motility, increased abnormalities and changes in the fluidity of the membrane as well as cell morphology. Moreover, the destruction of mitochondrial function could be the result of adverse influences of HS. The protein contents and enzymes of mitochondria were lowered after the exposure of sperm to HS. Some natural antioxidants were used for improving sperm mitochondrial function under HS conditions. In this review, it was highlighted the potential influences of HS on sperm function through reduction in ATP Synthesis yield, mitochondrial activity, mitochondrial protein contents and mitochondrial enzymes, which involves the interference of mitochondrial remodelling in sperm of animals.

Impacts of Heat Stress on Rabbit Immune Function, Endocrine, Blood Biochemical Changes, Antioxidant Capacity and Production Performance, and the Potential Mitigation Strategies of Nutritional Intervention

Heat stress has become a widespread concern in the world, which is one of the major environmental stressors and causes substantial economic loss in the rabbit industry. Heat stress leads to multiple damages to the health of rabbits, such as organ damage, oxidative stress, disordered endocrine regulation, suppressed immune function and reproductive disorders, ultimately, induces the decreased production performance and increased mortality. Nutritional approaches, including feeding strategies, adjusting feed formula, and supplementing vitamins, minerals, electrolytes, Chinese herbal medicines, and functional active substances to the feed, were reported to mitigate the detrimental effects of heat stress in rabbits. Therefore, elucidating the damage of heat stress to rabbits; proper management and nutritional approaches should be considered to solve the heat stress issue in rabbits. This review highlights the scientific evidence regarding the effects of heat stress on rabbit's immune function, endocrine, blood biochemical changes, antioxidant capacity and production performance, and the potential mitigation strategies of nutritional intervention to alleviate heat stress in rabbits; which could contribute to develop nutritional strategies in relieving heat stress of rabbits.

Acetyl l-carnitine protects adipose-derived stem cells against serum-starvation: regulation on the network composed of reactive oxygen species, autophagy, apoptosis and senescence

Adipose-derived stem cells (ADSCs) play an important role in cell therapy and regenerative medicine. However, local nutritional deficiency often limits therapeutical effect of the transplanted cells. Acetyl l-carnitine (ALC) is a common energy metabolism regulator and free radical scavenger. This study investigated the effect of ALC on ADSCs exposed to severe serum-deprivation and explored the relative machanisms. Treating with 1 mM ALC improved proliferation and alleviated senescence of starved cells, accompanied with reduced reactive oxygen species (ROS) and increased protein expression of SOD1 and catalase. In addition, ALC inhibited apoptosis but increased starvation-induced autophagy, which might be related to the regulation of phases of dissociation of Bcl-2-Beclin1 and Bcl-2-Bax complexes. Evidence obtained by replacing ALC with N-acetylcysteine (N-AC) suggested that ROS might be the central inducer of autophagy, apoptosis and senescence. There was a difference between ALC and N-AC in the protection mechanism, that was, compared with N-AC, ALC maintained autophagy well at the same time as anti-oxidation. Inhibition of autophagy by 3-methyladenine (3-MA) partially offset the protective effect of ALC. However, despite low-level ROS and enhanced autophagy, ALC with high concentration (10 mM) markedly aggravated cell apoptosis and senescence, thus losing cytoprotection and even causing damage.

l-carnitine modulates autophagy, oxidative stress and inflammation in trazodone induced testicular toxicity

BACKGROUND

Trazadone is an antidepressant and may affect reproductive hormones and spermatogenesis. l-carnitine is an amino acid that exhibits antioxidant actions. This study was designed to investigate the potential protective effects of l-carnitine against trazadone-induced testicular toxicity in male rats and the possible underlying mechanisms such as oxidative stress, inflammation and autophagy.

METHODS

thirty-two male Wistar rats were divided randomly into four groups (n = 8). Testicular damage was induced by oral administration of Trazadone (TRZ, 20 mg/kg/day, p.o.) for four weeks (TRZ group). l-carnitine (LC, 200 mg/kg/day, p.o.) was applied for four weeks (LC group). LC + TRZ group administered the same doses of LC and TRZ concomitantly. The control group received distilled water (as vehicle).

RESULTS

the protective treatment with LC attenuated the decline of sperm count and motility resulted from trazadone administration. Moreover, LC ameliorated trazadone increased lipid peroxidation (MDA) and reduction of total thiol and catalase activity. LC modulated the elevation in tumor necrosis factor- α (TNF-α), and increased the expression of autophagy related genes Becline-1, ATG 5, ATG-12 in rat testes. Serum level of FSH, LH and total testosterone were increased significantly (p < 0.001) in LC + TRZ group. Histopathological findings further supported the protective effects of LC against trazadone -induced testicular injury by increasing free sperms within the lumen of spermatogenic cells and improving testicular degeneration.

CONCLUSION

These findings supported the protective effects of l-carnitine on rat testes due to suppression of oxidative stress, inflammation and enhancing autophagy. l-carnitine may be recommended as adjuvant therapy to trazadone treatment.

Acetyl-L-carnitine confers neuroprotection against lipopolysaccharide (LPS) -induced neuroinflammation by targeting TLR4/NFκB, autophagy, inflammation and oxidative stress

Acetyl-L-carnitine has been shown to exert neuroprotection against neurodegenerative diseases. The present study was performed to evaluate neuroprotection effects of acetyl-L-carnitine against lipopolysaccharide (LPS) -induced neuroinflammation and clarify possible mechanisms. A single dose (500 µg/kg) of LPS was intraperitoneally injected to rats to induce model. The animals were intraperitoneally treated with different doses of acetyl-L-carnitine (30, 60, and 100) for 6 days. Y-maze task, single-trial passive avoidance and novel object recognition tests were used to evaluate memory impairments. ELISA assay was used to evaluate the expression of TLR4/NFκB, autophagic and oxidative stress markers. Our result showed that intraperitoneal injection of LPS resulted in initiation of neuroinflammation by activation of TLR4/NFκB, suppression of autophagic markers such as LC3 II/ LC3 I ratio and becline-1, and excessive production of ROS and MDA. Intraperitoneal administration of acetyl-L-carnitine contributed to neuroprotection against LPS -induced neuroinflammation by suppression of TLR4/NFκB pathway, restoring activity of autophagy and inhibition of oxidative stress. Collectively, our findings show that acetyl-L-carnitine attenuated LPS-induced neuroinflammation by targeting TLR4/NFκB pathway, autophagy and oxidative stress.