Expression Of MuRF1 Research Articles

Aptamer-Conjugated Exosomes Ameliorate Diabetes-Induced Muscle Atrophy by Enhancing SIRT1/FoxO1/3a-Mediated Mitochondrial Function.

Muscle atrophy is associated with Type 2 diabetes mellitus, which reduces the quality of life and lacks effective treatment strategies. Previously, it was determined that human umbilical cord mesenchymal stromal cell (hucMSC)-derived exosomes (EXOs) ameliorate diabetes-induced muscle atrophy. However, the systemic application of EXOs is less selective for diseased tissues, which reduces their efficacy and safety associated with their nonspecific biological distribution invivo. Therefore, improving exosomal targeting is imperative. In this study, a skeletal muscle-specific aptamer (Apt) was used to explore the effects of Apt-functionalized EXOs derived from hucMSCs in diabetes-associated muscle atrophy and its specific mechanisms. Diabetic db/db mice and C2C12 myotubes were used to explore the effects of MSC-EXOs or Apt-EXOs in alleviating muscle atrophy. Grip strength, muscle weight and muscle fibre cross-sectional area (CSA) were used to evaluate skeletal muscle strength and muscle mass. Western blot analysis of muscle atrophy signalling, including MuRF1 and Atrogin 1 and the mitochondrial complex and Seahorse analysis were performed to investigate the underlying mechanisms of MSC-EXOs or Apt-EXOs on muscle atrophy. MSC-EXOs increased grip strength (p = 0.0002) and muscle mass (p = 0.0044 for tibialis anterior (TA) muscle, p = 0.002 for soleus (SO) muscle) in db/db mice. It also increased the CSA of muscle fibres (p = 0.0011 for all fibres, p = 0.0036 for slow muscle fibres and p = 0.0089 for fast muscle fibres) and the percentage of slow-to-fast muscle fibres (p = 0.0109). However, Atrogin 1 (p = 0.0455) and MuRF1 expression (p = 0.0168) was reduced. MSC-EXOs activated SIRT1/FoxO1/3a signalling and enhanced mitochondrial function in db/db mice and C2C12 myotubes. SIRT1 knockdown decreased the beneficial antiatrophic effects of MSC-EXOs. Additionally, Apt conjugation increased the effect of MSC-EXOs on muscle atrophy and myofiber-type transition (p = 0.0133 for grip strength, p = 0.0124 for TA muscle weight, p = 0.0008 for SO muscle weight, p < 0.0001 for CSA of all muscle fibres, p = 0.0198 for CSA of slow muscle fibres, p = 0.0213 for CSA of fast muscle fibres, p = 0.011 for percentage of slow-fast muscle fibres, p = 0.0141 for Atrogin 1 expression and p = 0.005 for MuRF1 expression). The results suggest that hucMSC-derived exosomes ameliorate diabetes-associated muscle atrophy by enhancing SIRT1/FoxO1/3a-mediated mitochondrial function and that Apt conjugation strengthens the effects of MSC-EXOs on muscle atrophy. These findings demonstrate the therapeutic potential of muscle-targeted MSC-EXOs for the treatment of muscle atrophy.

Respiratory Muscle Injury Following Acute Monocled Cobra (Naja kaouthia) Envenoming: Histopathological Study in Rat Diaphragm

Clinical symptoms of monocled cobra (Naja kaouthia) envenoming include the paralysis of extraocular muscles, local tissue necrosis and death through respiratory failure. These neurotoxic outcomes are mainly due to the inhibitory action of postsynaptic neurotoxins to nicotinic acetylcholine receptors. However, injuries involving respiratory muscles have rarely been investigated. In this study, we determined the effect of N. kaouthia envenoming on morphological changes in the rat diaphragm. The efficacy of cobra monovalent antivenom in neutralising the histopathological effects of N. kaouthia venom was also evaluated. The intramuscular (i.m.) administration of N. kaouthia venom (2 mg/kg) caused skeletal muscle fibre atrophy and ruptures of myofibrils shown via a light microscope study. Transmission electron microscopy (TEM) revealed the zig-zagging of the Z-band, mitochondrial damages and degeneration of the synaptic fold of the neuromuscular junction following experimental cobra envenoming for 4 h. Intravenous administration of cobra antivenom at manufacturer-recommended doses diminished histopathological changes in the diaphragm following the administration of cobra venom. The expression of NF-kB and MuRF1 in the experimentally N. kaouthia-envenomed diaphragm indicated inflammation and tissue atrophy in the immunofluorescence analysis, respectively. In this study, we found that there were respiratory muscle injuries following N. kaouthia envenoming. The early administration of monovalent N. kaouthia antivenom is capable of neutralising neurotoxic outcomes following cobra envenoming.

Distinct Impact of Doxorubicin on Skeletal Muscle and Fat Metabolism in Mice: Without Dexrazoxane Effect

The chemotherapeutic agent doxorubicin (DOX) leads to the loss of skeletal muscle and adipose tissue mass, contributing to cancer cachexia. Experimental research on the molecular mechanisms of long-term DOX treatment is modest, and its effect on both skeletal muscle and adipose tissue has not been studied in an integrative manner. Dexrazoxane (DEXRA) is used to prevent DOX-induced cancer-therapy-related cardiovascular dysfunction (CTRCD), but its impact on skeletal muscle and adipose tissue remains elusive. Therefore, this study aimed to investigate the long-term effects of DOX on adipose tissue and skeletal muscle metabolism, and evaluate whether DEXRA can mitigate these effects. To this end, 10-week-old male C57BL6/J mice (n = 32) were divided into four groups: (1) DOX, (2) DOX-DEXRA combined, (3) DEXRA and (4) control. DOX (4 mg/kg weekly) and DEXRA (40 mg/kg weekly) were administered intraperitoneally over 6 weeks. Indirect calorimetry was used to assess metabolic parameters, followed by a molecular analysis and histological evaluation of skeletal muscle and adipose tissue. DOX treatment led to significant white adipose tissue (WAT) loss (74%) and moderate skeletal muscle loss (Gastrocnemius (GAS): 10%), along with decreased basal activity (53%) and energy expenditure (27%). A trend toward a reduced type IIa fiber cross-sectional area and a fast-to-slow fiber type switch in the Soleus muscle was observed. The WAT of DOX-treated mice displayed reduced Pparg (p &lt; 0.0001), Cd36 (p &lt; 0.0001) and Glut4 (p &lt; 0.05) mRNA expression—markers of fat and glucose metabolism—compared to controls. In contrast, the GAS of DOX-treated mice showed increased Cd36 (p &lt; 0.05) and Glut4 (p &lt; 0.01), together with elevated Pdk4 (p &lt; 0.001) mRNA expression—suggesting reduced carbohydrate oxidation—compared to controls. Additionally, DOX increased Murf1 (p &lt; 0.05) and Atrogin1 (p &lt; 0.05) mRNA expression—markers of protein degradation—compared to controls. In both the WAT and GAS of DOX-treated mice, Ppard mRNA expression remained unchanged. Overall, DEXRA failed to prevent these DOX-induced changes. Collectively, our results suggest that DOX induced varying degrees of wasting in adipose tissue and skeletal muscle, driven by distinct mechanisms. While DEXRA protected against DOX-induced CTRCD, it did not counteract its adverse effects on skeletal muscle and adipose tissue.

Role of PI3 Kinases in Cell Signaling and Soleus Muscle Atrophy During Three Days of Unloading.

During skeletal muscle unloading, phosphoinositide 3-kinase (PI3K), and especially PI3K gamma (PI3Kγ), can be activated by changes in membrane potential. Activated IP3 can increase the ability of Ca2+ to enter the nucleus through IP3 receptors. This may contribute to the activation of transcription factors that initiate muscle atrophy processes. LY294002 inhibitor was used to study the role of PI3K in the ATP-dependent regulation of skeletal muscle signaling during three days of unloading. Inhibition of PI3K during soleus muscle unloading slows down the atrophic processes and prevents the accumulation of ATP and the expression of the E3 ubiquitin ligase MuRF1 and ubiquitin. It also prevents the increase in the expression of IP3 receptors and regulates the activity of Ca2+-dependent signaling pathways by reducing the mRNA expression of the Ca2+-dependent marker calcineurin (CaN) and decreasing the phosphorylation of CaMKII. It also affects the regulation of markers of anabolic signaling in unloaded muscles: IRS1 and 4E-BP. PI3K is an important mediator of skeletal muscle atrophy during unloading. Developing strategies for the localized skeletal muscle release of PI3K inhibitors might be one of the future treatments for inactivity and disease-induced muscle atrophy.

3-(4-Hydroxy-3-methoxyphenyl) propionic acid mitigates dexamethasone-induced muscle atrophy by attenuating Atrogin-1 and MuRF-1 expression in mouse C2C12 skeletal myotubes

3-(4-Hydroxy-3-methoxyphenyl) propionic acid is an in vivo metabolite of 4-hydroxy-3-methoxycinnamic acid which is abundantly found in coffee bean, rice bran, fruits, and vegetables. Previous studies reported that polyphenols and their metabolites exhibit positive effects on muscle health. Thus, the effect of 3-(4-hydroxy-3-methoxyphenyl) propionic acid on muscle atrophy induced by dexamethasone was investigated using mouse C2C12 skeletal myotubes. Dexamethasone treatment (10 ‍μM) reduced the diameter and myosin heavy chain protein expression in C2C12 myotubes; it also increased muscle atrophy-associated ubiquitin ligases, such as muscle atrophy F-box protein 1/Atrogin-1 and muscle ring finger protein-1, along with their upstream regulator Krüppel-like factor 15. Dexamethasone dephosphorylated FoxO3a transcription factor and increased total FoxO3a expression. Interestingly, 10 ‍μM 3-(4-hydroxy-3-methoxyphenyl) propionic acid treatment significantly attenuated dexamethasone-induced reduction in myotube thickness and muscle protein degradation and suppressed muscle atrophy-associated ubiquitin ligases. 3-(4-Hydroxy-3-methoxyphenyl) propionic acid also prevented dexamethasone-induced Krüppel-like factor 15 and FoxO3a expression. In conclusion, these results suggest that in vivo metabolite of polyphenols per se could be the real origin of the anti-muscular atrophy activity, as 3-(4-hydroxy-3-methoxyphenyl) propionic acid ameliorated glucocorticoid-induced muscle atrophy by suppressing Atrogin-1 and MuRF-1.

Prevention of Muscle Atrophy by Low-Molecular-Weight Fraction from Hirsutella sinensis Mycelium.

Muscle atrophy, an age-related condition, presents a growing healthcare concern within the context of global population aging. While studies have investigated Hirsutella sinensis for its potential antifatigue properties, reports on its active components remain limited. This study evaluated the efficacy of H. sinensis mycelium extract on muscle health, utilizing a 1:1 water-ethanol preparation administered to C57BL/6 mice exhibiting acute hind leg atrophy. The results indicated no adverse effects, with significant improvements in muscle endurance and soleus muscle mass observed over a 14-day period. To further elucidate the mechanisms and effects of H. sinensis mycelium on dexamethasone-induced muscle atrophy, the water extract was fractionated into components of <3.5 kDa, 3.5-10 kDa, and >10 kDa using dialysis membranes. The investigation utilized a C2C12 cell atrophy model, induced by dexamethasone, to analyze the expression of relevant genes via qPCR. The results demonstrated that the <3.5 kDa and >10 kDa fractions significantly upregulated the expression of Myh2 and Myh7 genes while simultaneously downregulating the expression of MuRF-1 and Atrogin-1. It is noteworthy that the <3.5 kDa fraction exclusively enhanced MYHC protein expression and suppressed AMPK expression, as confirmed by Western blot analysis. This comprehensive pilot study suggests that the low-molecular-weight fraction of H. sinensis mycelium exhibits considerable potential for muscle mass preservation and atrophy mitigation. As a result, it offers a promising direction for the development of supplements aimed at addressing fatigue and preventing muscle atrophy.

Entacapone alleviates muscle atrophy by modulating oxidative stress, proteolysis, and lipid aggregation in multiple mice models

BackgroundSkeletal muscle atrophy significantly affects quality of life and has socio-economic and health implications. This study evaluates the effects of entacapone (ENT) on skeletal muscle atrophy linked with oxidative stress and proteolysis.MethodsC2C12 cells were treated with dexamethasone (Dex) to simulate muscle atrophy. Four murine models were employed: diaphragm atrophy from mechanical ventilation, Dex-induced atrophy, lipopolysaccharide (LPS)-induced atrophy, and hyperlipidemia-induced atrophy. Each model utilized entacapone (10 mg/kg), with sample sizes: Control (9), MV (11), MV + ENT (5) for diaphragm atrophy; Control (4), Dex (4), Dex + ENT (5) for Dex model; Control (4), LPS (4), LPS + ENT (5) for LPS model; and similar for hyperlipidemia. Measurements included muscle strength, myofiber cross-sectional area (CSA), proteolysis, oxidative stress markers [uperoxide dismutase 1 (SOD1), uperoxide dismutase 2 (SOD2), 4-hydroxynonenal (4-HNE)], and lipid levels.ResultsOur findings confirm Dex-induced muscle atrophy, evidenced by increased expression of muscle atrophy-associated proteins, including Atrogin-1 and Murf-1, along with decreased diameter of C2C12 myotubes. Atrogin-1 levels rose by 660.6% (p &amp;lt; 0.05) in the Dex group compared to control, while entacapone reduced Atrogin-1 by 84.4% (p &amp;lt; 0.05). Similarly, Murf-1 levels increased by 365% (p &amp;lt; 0.05) in the Dex group and were decreased by 89.5% (p &amp;lt; 0.05) with entacapone. Dexamethasone exposure induces oxidative stress, evidenced by the upregulation of oxidative stress-related proteins Sod1, Sod2, and 4-HNE. Entacapone significantly reduced the levels of these oxidative stress markers, enhancing GSH-PX content by 385.6% (p &amp;lt; 0.05) compared to the Dex-treated group. Additionally, ENT effectively reduced the Dex-induced increase in MDA content by 63.98% (p &amp;lt; 0.05). Furthermore, entacapone effectively prevents the decline in diaphragm muscle strength and myofiber CSA in mice. It also mitigates diaphragm oxidative stress and protein hydrolysis. Additionally, entacapone exhibits the ability to attenuate lipid accumulation in the gastrocnemius muscle of hyperlipidemic mice and alleviate the reduction in muscle fiber CSA.ConclusionOur findings suggest that entacapone is a promising therapeutic candidate for muscle atrophy, functioning through the reduction of oxidative stress, proteolysis, and lipid aggregation. Future research should explore the underlying mechanisms and potential clinical applications of entacapone in muscle-wasting conditions.

Aerobic plus resistance exercise attenuates skeletal muscle atrophy induced by dexamethasone through the HDAC4/FoxO3a pathway.

This study aimed to investigate the underlying mechanisms by which physical exercise mitigates muscle atrophy induced by Dexamethasone (Dex). A muscle atrophy model was established in the mouse C2C12 cell line and 8-week-old mice treated with Dex, with subsequent verification of phenotype and atrogene expression. The potential benefits of combined aerobic and resistance exercise in mitigating muscle atrophy were then examined. To elucidate the involvement of Histone deacetylase 4 (HDAC4) in the protective effects of exercise against muscle loss, a combination of RT-PCR, Western blotting, immunoprecipitation, and immunofluorescence staining techniques were employed. The upregulation of HDAC4 was observed following Dex-induced muscle atrophy in vitro and in vivo. Inhibition of HDAC4 in C2C12 cells resulted in an increase in myotube diameter and fusion index, along with a decrease in the expression of Atrogin-1 and MuRF1. Treatment with Tasquinimod, an HDAC4 inhibitor, effectively prevented muscle wasting and dysfunction in mice induced by Dex. After a 6-week exercise intervention, the Dex-Exercise group exhibited significant improvements in body fat level, hyperinsulinemia, muscle mass and function in comparison to the Dex-Sedentary group. Mechanistically, we discovered that HDAC4 bound to and deacetylated Forkhead box protein O 3a (FoxO3a) within the nucleus, leading to decreased phosphorylation of FoxO3a at Ser 253. This interaction subsequently facilitated the expression of downstream atrogene Atrogin-1 and MuRF1, resulting in muscle atrophy. Conversely, exercise was found to potentially mitigate muscle atrophy by inhibiting the HDAC4/FoxO3a pathway. These findings suggest that HDAC4 may be a potential therapeutic target for exercise to combat Dex-induced muscle atrophy.

Melatonin attenuates sepsis-induced muscle atrophy by regulating the PI3K/Akt signaling pathway

BackgroundIn intensive care units, sepsis-related muscle atrophy is a severe complication of numerous diseases, yet the underlying mechanism and potential therapeutic options remain elusive. Recent research has identified melatonin as a promising candidate for attenuating organ dysfunction triggered by sepsis. MethodsWe used in vitro and in vivo models to simulate sepsis, C2C12 myotubes were treated with LPS, and the mice underwent cecal ligation and puncture (CLP) surgery. Following a pretreatment regimen involving melatonin and the AKT inhibitor MK-2206 2HCl, we analyzed changes in p-Akt and MuRF1 protein levels, fiber cross-sectional areas, and myotube diameters. The analyses included RNA sequencing, Western blotting, qRT–PCR, and immunofluorescence staining. ResultsActivation of the PI3K/Akt pathway in skeletal muscle occurred 24 h post-CLP surgery in mice. This was accompanied by upregulated MuRF1 expression and reduced muscle fiber cross-sectional area, which culminated in muscle atrophy. However, these detrimental effects were attenuated when the mice were pretreated with melatonin via intraperitoneal injection for seven consecutive days. Similarly, LPS treatment of C2C12 myotubes activated the PI3K/Akt pathway, elevated MuRF1 expression, and markedly reduced myotube diameter after 48 h, leading to muscle atrophy. Pretreatment of C2C12 myotubes with melatonin 24 h in advance mitigated these adverse effects. However, cotreatment of C2C12 myotubes with melatonin and MK-2206 2HCl attenuated the beneficial effects of melatonin. ConclusionMelatonin can attenuate sepsis-induced muscle atrophy by regulating the PI3K/Akt pathway.

Tetrandrine induces muscle atrophy involving ROS-mediated inhibition of Akt and FoxO3

Tetrandrine (Tet), a well-known drug of calcium channel blocker, has been broadly applied for anti-inflammatory and anti-fibrogenetic therapy. However, due to the functional diversity of ubiquitous calcium channels, potential side-effects may be expected. Our previous report revealed an inhibitory effect of Tet on myogenesis of skeletal muscle. Here, we found that Tet induced protein degradation resulting in the myofibril atrophy. Upon administration with a relative high dose (40 mg/kg) of Tet for 28 days, the mice displayed significantly reduced muscle mass, strength force, and myosin heavy chain (MyHC) protein levels. The MyHC reduction was further detected in C2C12 myotubes after treating with Tet. Interestingly, the expression of Atrogin-1 and Murf-1, the skeletal muscle specific E3 ligases of protein ubiquitin–proteasome system (UPS), was accordingly up-regulated, and the reduced MyHC was significantly mitigated by MG132, a 26S proteasome inhibitor, indicating a key role of UPS in the protein degradation of muscle cells. Further study showed that Tet induced autophagy also participated in the protein degradation. Mechanistically, Tet treatment caused ROS production in myotubes that in turn targeted on FoxO3/AKT signaling, resulting in the activation of UPS and autophagy processes that were involved in the protein degradation. Our study reveals a potential side-effect of Tet on skeletal muscle atrophy, particularly when the drug dose is relatively high.

Treatment with tofacitinib attenuates muscle loss through myogenin activation in the collagen-induced arthritis

BackgroundSarcopenia is a muscle disease characterized by reduction of muscle strength and muscle mass. In RA, 25.9 to 43.3% of the patients present sarcopenia. The loss of muscle mass observed in RA patients occurs either by activation of catabolic pathways or by inhibition of anabolic pathways. Despite having a list of drugs capable of treating RA inflammation, their effect on muscle is unclear. Our objective was to evaluate the tofacitinib effect on the muscle mass of collagen-induced arthritis (CIA) mice.MethodsCIA was induced in male DBA/1J mice by subcutaneous injection of Type 2 Collagen plus Freund Adjuvant. Animals were randomized into 3 groups: CIA + tofacitinib; CIA + vehicle; and healthy controls. Treatment was administered twice a day, between days 18 and 45 after induction. Clinical score, edema, and body weight were evaluated during the experimental period. After euthanasia, tibiotarsal joints were collected for assessment of disease histopathological score, and tibialis anterior (TA) and gastrocnemius (GA) muscles were weighed to assess muscle mass. Muscle atrophy was evaluated by measurement of TA myofiber cross-sectional area (CSA). Protein expression was evaluated by western blot using GA homogenates. Serum inflammatory markers were evaluated by ELISA. Statistical analysis included ANOVA followed by Tukey’s or with Kruskal-Wallis. The statistical difference was assumed for p < 0.05.ResultsTofacitinib treatment decreased arthritis severity by reducing clinical score, and hind paw edema in comparison with the vehicle group. Tofacitinib showed weight gain, higher TA and GA weights, and increased CSA compared to the vehicle group. On day 45, Tofacitinib presented increased muscle strength compared to the vehicle group, however, no difference was found in muscle fatigue. Pax7 expression was unchanged, while MyoD expression showed an increasing trend, and myogenin expression was significantly increased in Tofacitinib compared to vehicle and control groups. The treatment didn’t modify Murf-1 expression. Tofacitinib mice showed decreased serum levels of TNF and increased IL-6 serum levels.ConclusionTofacitinib attenuated muscle loss in arthritic mice, increased muscle weight and muscle CSA. Activation of satellite cell regeneration, based on the increased expression of myogenin, is a potential mechanism involved in tofacitinib action against muscle loss.

Amelioration of Cancer Cachexia by Dalbergia odorifera Extract Through AKT Signaling Pathway Regulation.

Background/Objectives: Cancer cachexia is a multifactorial syndrome characterized by the progressive loss of skeletal muscle mass and adipose tissue. Dalbergia odorifer is widely used in traditional medicine in Korea and China to treat various diseases. However, its exact role and underlying mechanism in regulating cancer cachexia have not been elucidated yet. This research was conducted to investigate the effect of D. odorifer extract (DOE) in preventing the development of cancer-induced cachexia symptoms and figure out the relevant mechanisms. Methods: A cancer cachexia model was established in Balb/c mice using the CT26 colon carcinoma cell line. To evaluate the anti-cachexia effect of Dalbergia odorifer extract (DOE), CT26-bearing mice were orally administered with DOE at concentrations of 50 and 100 mg/kg BW for 14 days. C2C12 myotubes and 3T3L1 adipocytes were treated with 80% CT26 conditioned medium, DOE, and wortmannin, a particular AKT inhibitor to determine the influence of DOE in the AKT signaling pathway. Mice body weight, food intake, myofiber cross-sectional area, adipocyte size, myotube diameter, lipid accumulation, and relevant gene expression were analyzed. Results: The oral administration of DOE at doses of 50 and 100 mg/kg body weight to CT26 tumor-bearing mice resulted in a significant reduction in body weight loss, an increase in food intake, and a decrease in serum glycerol levels. Furthermore, DOE treatment led to an increase in muscle mass, larger muscle fiber diameter, and elevated expression levels of MyH2 and Igf1, while simultaneously reducing the expression of Atrogin1 and MuRF1. DOE also attenuated adipose tissue wasting, as evidenced by increased epididymal fat mass, enlarged adipocyte size, and upregulated Pparγ expression, alongside a reduction in Ucp1 and IL6 levels. In cachectic C2C12 myotubes and 3T3-L1 adipocytes induced by the CT26 conditioned medium, DOE significantly inhibited muscle wasting and lipolysis by activating the AKT signaling pathway. The treatment of wortmannin, a specific AKT inhibitor, effectively neutralized DOE's impact on the AKT pathway, myotube diameter, and lipid accumulation. Conclusions: DOE ameliorates cancer cachexia through the expression of genes involved in protein synthesis and lipogenesis, while suppressing those related to protein degradation, suggesting its potential as a plant-derived therapeutic agent in combating cancer cachexia.

HouShiHeiSan attenuates sarcopenia in middle cerebral artery occlusion (MCAO) rats

Ethnopharmacological relevancePhysical therapy is the main clinical treatment for limb symptoms after ischemic stroke, and there is a lack of reliable drug intervention programs. HouShiHeiSan (HS)comes from “Synopsis of the Golden Chamber”, where it is recorded: “seauelae of wind stroke and heaviness of limbs”, indicating this formulae is a promising opion for clinical practice. Aim of the studyThe aim of this study is to explore the therapeutic effect of HS on sarcopenia after ischemic stroke (ISS) by using the middle cerebral artery occlusion (MCAO) rats. Materials and methodsAfter 7 days of adaptive feeding Sprague-Dawley (SD) rats were randomly divided into sham and MCAO surgery groups. After MCAO operation, the agreement of the models was evaluated with a laser speckle instrument, and then, treatment groups were administered HS and related solvent. During the 7 days treatment period, the Zea-Longa score was used to assess the neural function, the treadmill for exercise capacity and traction instrument for grip strength. Besides, the physiological electrical signal system was used to record muscular electrical signals, while the muscle thickness was measured by ultrasound. After data acquisition on the 7th day after MCAO operation, the soleus muscle was dissected, and the indexes of length, weight of whole muscle tissue and cross-sectional area of muscular cells by H&E were recorded. Subsequently, mechanistic indicators were examined. MuRF1 and MAFbx expression was detected by immunohistochemistry (IHC). Furthermore, the expression level of more related indicators of muscular differentiation and cellular proterin balance, including mTOR, p-mTOR, AKT, p-AKT, p70s6k, p-p70s6, FOXO1, p-FOXO1, MyoD1, Myostatin, MuRF1 and MAFbx, were tested via Western blot. ResultsHS improved motor performance and promoted muscle regeneration in MCAO rats. In terms of motor ability, HS mixed with alcohol significantly improved the neurological function damage, reduce the weight loss, increase the running distance per unit time and increase the grip strength. The postoperative muscle electrical signal intensity increased, and muscle thickness, weight, and length were maintained. The HS with alcohol group significantly maintained the cross-sectional size of muscle cells and reduced the number of MyoD1 and myostatin-positive cells in the muscle tissue. It simultaneously promoted the expression of p-mTOR, p-AKT, p-p70s6k, and MyoD1 to promote the synthesis of muscle proteins and inhibited the expression of p-FOXO1, myostatin, MAFbx, and MuRF1 to reduce muscle protein degradation. ConclusionHS can enhance muscle protein synthesis and decrease protein breakdown by activating the AKT/mTOR/FOXO1 pathway, thereby preserving muscle health and enhancing motor performance following stroke in rats.

Alterations in FoxO3a, NF-κB, and MuRF1 Expression in the Soleus Muscle of Male Rats Following High-Intensity Interval Training and Detraining.

Activation of the transcription factors FoxO3a and NF-κB is necessary for muscle atrophy, which occurs during cancer cachexia and detraining. It is not known how high-intensity interval training (HIIT) and detraining affect activation of these pathways. Two-month-old male Sprague-Dawley rats were assigned to sedentary control (SC) (n = 6) and HIIT (HIIT) (n = 18) groups. The HIIT group was divided into three subgroups: HIIT (n = 6), HIIT + 7-day detraining (n = 6), and HIIT + 14-day detraining (n = 6). The expression of FoxO3a, NF-κB, MuRF1, and PGC-1α in the soleus muscle was examined by RT-PCR using CYBR Green. The 2-Ct, Livak method was used to calculate the changes in data expression. The soleus muscle mass increased after HIIT (35.10%) and decreased after 7- and 14-day of detraining (15 and 21%, respectively). The mRNA expression levels of NF-κB, MuRF1, and PGC1α in the soleus muscle were upregulated, and FoxO3a levels were significantly lower in the HIIT group compare to the SC group (p = 0.001). Taken together, the activity of the FoxO3a/MuRF1 pathway, but not NF-κB /MuRF1, can promote atrophy due to detraining, and MuRF1 is not always a good marker of atrophy.

Fu-Zheng-Li-Fei Recipe (FZLFR) in the treatment of cancer cachexia: Exploration of the efficacy and molecular mechanism based on chemical characterization, experimental research and network pharmacology

Ethnopharmacological relevanceFZLFR was derived from a classic traditional Chinese medicine recipe, the Shiquan-Dabu decoction. FZLFR is commonly used in clinical practice to address muscle loss and associated cancer cachexia. However, the mechanism of by which FZLFR acts in cancer cachexia remains unclear. AimThis study aimed to assess the effects and explore the potential mechanism of action of FZLFR in treating cancer cachexia. MethodsCancer cachexia was induced by inoculating Lewis lung carcinoma cells into the right flank of male C57BL/6 mice. The efficacy of FZLFR was evaluated by comparing changes in body weight, tumor mass, food intake, survival time, weight, and cross-sectional area of the gastrocnemius and anterior tibial muscles. Moreover, inflammatory cytokines, such as TNF-α and IL-6, were detected by ELISA. The chemical components of FZLFR were analyzed using ultra-performance liquid chromatography-coupled with time-of-flight mass spectrometry. Network pharmacology analysis was performed to screen the core targets and potential pathways involved in FZLFR treatment of cancer cachexia. Molecular docking was used to analyze the binding ability of the core targets and key compounds. The expression levels of core targets and targets correlated with skeletal muscle atrophy were also assessed using western blotting. ResultsFZLFR enhanced the food intake and survival rate of mice with cancer cachexia. It also alleviated tumor-induced body weight loss, tumor growth, and muscle fiber atrophy in these mice. Additionally, it improved the weight and cross-sectional area of the gastrocnemius and anterior tibial muscles. FZLFR down-regulated the serum levels of TNF-α and IL-6. UPLC-ESI-Q-TOF-MS analysis identified 184 compounds in FZLFR. Network pharmacology analysis predicted that TNF signaling pathway, ErbB signaling pathway and VEGF signaling pathway might be essential in FZLFR action. Molecular docking showed that kaempferol, upafolin, apigenin, and luteolin might play key roles in FZLFR treatment. Moreover, FZLFR decreased MAFBx1, MURF1, NF-κB, TWEAK, MAPK8, and EGFR expression levels. FZLFR enhanced the expression of VEGFA and ESR1, as demonstrated by western blotting. ConclusionsFZLFR increased food intake and alleviated muscle atrophy in mice with cancer cachexia. The potential pharmacological mechanisms underlying its anticachexia effects include reducing inflammation, enhancing muscle vascular growth, inhibiting tumor angiogenesis, and modulating estrogen receptors.

Changes in Skeletal Muscle Atrophy over Time in a Rat Model of Adenine-Induced Chronic Kidney Disease

This study evaluated changes over time in skeletal muscle atrophy, expressions of skeletal muscle anabolic and catabolic genes, and mitochondrial activity by skeletal muscle type in an adenine-induced chronic kidney disease (CKD) model. A CKD model was successfully established by feeding male Wistar rats a 0.75% adenine diet for 4 weeks starting at 8 weeks of age. Control and CKD groups were sacrificed at 12 and 20 weeks of age. The back muscles were analyzed histologically, and succinate dehydrogenase (SDH) staining was performed to evaluate mitochondrial activity. Gene expressions of myogenic determination gene number 1 and myogenin as indicators of muscle anabolism, atrogin-1 and muscle RING-finger protein-1 (MuRF1) as indicators of muscle catabolism, and peroxisome proliferator-activated receptor-γ coactivator-1-α as a marker of mitochondrial biogenesis were assessed. Type I and type II muscle cross-sectional areas (CSAs) were decreased at 12 weeks, but type I muscle CSA was recovered at 20 weeks. SDH staining was lower in CKD than in control rats at 12 weeks, but no significant difference was observed at 20 weeks. Increased expressions of myogenin, atrogin-1, and MuRF-1 were observed only at 12 weeks, but no differences were observed at 20 weeks. The adenine-induced CKD rat model appears to show changes in muscle atrophy over time.

Effect of different doses of whey proteins on muscle strength, body composition and gene expression of mTOR and MuRF-1 in trained Wistar rats

Introduction: The combination of resistance training (RT) and whey protein supplementation (WPS) is widely practiced by both athletes and recreational exercisers to promote muscle growth and increase strength. Objectiveː This study examined the effect of different doses of whey proteins on muscle strength, body composition and gene expression of mTOR and MuRF-1 in trained Wistar rats. Methodsː 80 male Wistar rats were divided into 8-groups (n=10): sedentary control (C), RT-control (TC), groups consuming whey protein at varying doses (W2, W4, and W6; respectively 2/4/6g/kg/day), and groups consuming whey protein at varying doses combined to RT (TW2, TW4, and TW6; respectively 2/4/6g/kg/day). The RT program was conducted for 12 weeks, three days a week, with the training intensity increasing from 50 to 100% of the rats' body weight. The rats receiving the whey supplement via the gavage method based on their body weight. Resultsː Muscle strength significantly increased in all trained groups (p&lt;0.0001), with a more significant increase in the groups RT and WPS combined. In addition, the expression of mTOR was higher in the RT groups compared to the sedentary groups (p&lt;0.01), but supplementation did not yield significant differences. WPS decreased MuRF-1 expression (p&lt;0.01) independently of RT. Conclusionː In conclusion, RT combined with WPS for 12 weeks improved muscle strength. Furthermore, mTOR expression increased in trained rats, but not in sedentary rats who used different doses of WPS. However, WPS at any dose reduced MuRF-1 expression, independently of RT. Higher WPS doses did not enhance observed gains compared to a lower dose. Keywords: whey protein, body composition, resistance training, mTOR, MuRF-1.

6979 Effect of Orchiectomy on Muscle Growth and Differentiation Factors in Male Mice With Kidney Disease

Abstract Disclosure: O. Marks: None. J. Bruno: None. D. Wu: None. A. Patwardhan: None. Y. Komaru: None. G. Ling: None. E. Kefalogianni: None. R. Aurora: None. S.S. Dhindsa: None. A. Herrlich: None. Background: Sarcopenia and frailty are major clinical concerns in participants with chronic kidney disease (CKD). In males, an additional factor contributes to the development of sarcopenia. Around half of the men with CKD have subnormal serum testosterone (T) concentrations. The mechanisms that underlie the effect of low T concentrations on muscle growth in CKD are not known. In this study, we performed orchiectomy in male mice with kidney disease and evaluated the expression and protein content of the following muscle growth and differentiation factors. Methods: Forty mice were divided into 4 groups: 1) renal injury, induced by ischemia-induced reperfusion (IRI, N=11) at 2 months of age; 2) orchidectomy (ORX), performed 4 weeks after IRI (IRI + ORX, N=9); 3) sham-IRI and ORX (sham-ORX, N=8); and 4) sham-sham surgery (N=12). The mice were sacrificed when they were ∼7 months old (mean age 206±13 days). Gastrocnemius and levator ani muscles were harvested to measure expression by RT-qPCR of muscle catabolism markers (Atrogin-1 and ubiquitin ligase MuRF1), muscle growth inhibitors, myostatin and myogenic regulatory factor (Mrf4), fibroblast growth factor-2 (FGF2, a stimulator of satellite stem cells) and its receptor FGFR2, androgen receptor (AR) and IGF-1. Results: The mean BUN (blood urea nitrogen) at the time of sacrifice was higher in the IRI/ORX (32±4 mg/dl) and IRI/Sham (26±5 mg/dl) groups as compared to sham-sham (21±5 mg/dl, p&amp;lt;0.05 for both). There was a significant reduction (p&amp;lt;0.05) in the expression of myostatin (by 41%), Mrf4 (29%), atrogin-1 (51%) and MuRF1 (32%) in gastrocnemius muscle from the ORX-IRI and ORX-sham groups, while there was no difference in FGF2 and FGFR2, as compared to sham-sham group. Data from levator ani muscle (the most androgen sensitive muscle in mammals) showed increases in AR (64%) and Atrogin-1 (66%); and decreases in IGF-1 (88%) and myostatin (86%) in ORX-IRI and ORX-sham groups. Consistent with the mRNA expression, we found a drastic decline in protein content of myostatin in gastrocnemius (85%) in ORX-IRI and ORX-sham groups as compared to sham-sham (p=0.04). Conclusions: These data show that ORX in mice with renal injury is associated with changes in muscle growth and differentiation factors. Myostatin was the most affected gene, with 41-86% decline in mRNA and protein. These data are informative for attempts to develop treatments for sarcopenia in patients with kidney disease. Limitations: Our experimental model differs in some respects from hypogonadal men with CKD. ORX results in complete elimination of T, and thus much lower T concentrations than in men with kidney disease. There is a recovery of kidney function after IRI. We sacrificed the mice 5 months after renal injury was inflicted. Hence, the effect of IRI on muscle growth genes may have been different immediately following IRI. Thus, the impact of ORX was more apparent than of IRI in our study. Presentation: 6/1/2024

6979 Effect of Orchiectomy on Muscle Growth and Differentiation Factors in Male Mice With Kidney Disease

Abstract Disclosure: O. Marks: None. J. Bruno: None. D. Wu: None. A. Patwardhan: None. Y. Komaru: None. G. Ling: None. E. Kefalogianni: None. R. Aurora: None. S.S. Dhindsa: None. A. Herrlich: None. Background: Sarcopenia and frailty are major clinical concerns in participants with chronic kidney disease (CKD). In males, an additional factor contributes to the development of sarcopenia. Around half of the men with CKD have subnormal serum testosterone (T) concentrations. The mechanisms that underlie the effect of low T concentrations on muscle growth in CKD are not known. In this study, we performed orchiectomy in male mice with kidney disease and evaluated the expression and protein content of the following muscle growth and differentiation factors. Methods: Forty mice were divided into 4 groups: 1) renal injury, induced by ischemia-induced reperfusion (IRI, N=11) at 2 months of age; 2) orchidectomy (ORX), performed 4 weeks after IRI (IRI + ORX, N=9); 3) sham-IRI and ORX (sham-ORX, N=8); and 4) sham-sham surgery (N=12). The mice were sacrificed when they were ∼7 months old (mean age 206±13 days). Gastrocnemius and levator ani muscles were harvested to measure expression by RT-qPCR of muscle catabolism markers (Atrogin-1 and ubiquitin ligase MuRF1), muscle growth inhibitors, myostatin and myogenic regulatory factor (Mrf4), fibroblast growth factor-2 (FGF2, a stimulator of satellite stem cells) and its receptor FGFR2, androgen receptor (AR) and IGF-1. Results: The mean BUN (blood urea nitrogen) at the time of sacrifice was higher in the IRI/ORX (32±4 mg/dl) and IRI/Sham (26±5 mg/dl) groups as compared to sham-sham (21±5 mg/dl, p&amp;lt;0.05 for both). There was a significant reduction (p&amp;lt;0.05) in the expression of myostatin (by 41%), Mrf4 (29%), atrogin-1 (51%) and MuRF1 (32%) in gastrocnemius muscle from the ORX-IRI and ORX-sham groups, while there was no difference in FGF2 and FGFR2, as compared to sham-sham group. Data from levator ani muscle (the most androgen sensitive muscle in mammals) showed increases in AR (64%) and Atrogin-1 (66%); and decreases in IGF-1 (88%) and myostatin (86%) in ORX-IRI and ORX-sham groups. Consistent with the mRNA expression, we found a drastic decline in protein content of myostatin in gastrocnemius (85%) in ORX-IRI and ORX-sham groups as compared to sham-sham (p=0.04). Conclusions: These data show that ORX in mice with renal injury is associated with changes in muscle growth and differentiation factors. Myostatin was the most affected gene, with 41-86% decline in mRNA and protein. These data are informative for attempts to develop treatments for sarcopenia in patients with kidney disease. Limitations: Our experimental model differs in some respects from hypogonadal men with CKD. ORX results in complete elimination of T, and thus much lower T concentrations than in men with kidney disease. There is a recovery of kidney function after IRI. We sacrificed the mice 5 months after renal injury was inflicted. Hence, the effect of IRI on muscle growth genes may have been different immediately following IRI. Thus, the impact of ORX was more apparent than of IRI in our study. Presentation: 6/1/2024

Exploring the Therapeutic Potential of Green Tea (Camellia sinensis L.) in Anti-Aging: A Comprehensive Review of Mechanisms and Findings.

Green tea (GT) is rich in Phyto-active compounds such as epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), epicatechin (EC), catechin, and tannic acid, which exhibit synergistic effects when combined. Preclinical studies demonstrate that GT and its compounds can reduce reactive oxygen species (ROS), enhance antioxidant capacity, and alleviate aging-related issues such as memory impairments, cognitive decline, and shortened lifespan. Clinical trials corroborate the efficacy of topical GT formulations in improving skin tone, texture, and elasticity and reducing wrinkles. The present manuscript summarizes the recent update on the anti-aging potential of GT and its possible mechanisms. The literature survey suggested that GT consumption is linked to improved cognition, reduced depression levels, and activation of pathways in model organisms like C. elegans. Additionally, tea polyphenols enhance fibroblast mitophagy, boost hippocampal synaptic plasticity in rodents, and mitigate age-related cognitive decline. Moreover, EGCG exhibits anti-aging properties by reducing TNF-induced MMP-1 expression, suppressing ERK signaling, and inhibiting MEK and Src phosphorylation in human dermal fibroblasts. In the context of skin permeation and deposition, optimized transpersonal formulation (TF) incorporating EGCG and hyaluronic acid (HA) demonstrated significantly increased skin permeation and deposition of EGCG compared to plain EGCG. Furthermore, EGCG protects cardiomyocytes via the PPARγ pathway and combats age-related muscle loss through miRNA-486-5p regulation, AKT activation, and FoxO1a-mediated expression of MuRF1 and Atrogin-1. In conclusion, the regular consumption of GT holds promise for promoting physical and mental health, delaying brain and skin aging, and improving overall health by enhancing total antioxidant capacity.