The Autophagy Regulatory Molecule CSRP3 Interacts with LC3 and Protects Against Muscular Dystrophy

Genetic background of walking ability and its relationship with leg defects, mortality, and performance traits in turkeys (Meleagris gallopavo)

This study aimed to explore the genetic basis of walking ability and potentially related performance traits in turkey purebred populations. Phenotypic, pedigree, and genomic datasets from 2 turkey lines hatched between 2010 and 2023 were included in the study. Walking ability data, defined based on a scoring system ranging from 1 (worst) to 6 (best), were collected on 192,019 animals of a female line and 235,461 animals of a male line. Genomic information was obtained for 46,427 turkeys (22,302 from a female line and 24,125 from a male line) using a 65K single nucleotide polymorphism (SNP) panel. Variance components and heritability for walking ability were estimated. Furthermore, genetic and phenotypic correlations among walking ability, mortality and disorders, and performance traits were calculated. A genome-wide association study (GWAS) was also conducted to identify SNPs associated with walking ability. Walking ability is moderately heritable (0.23 ± 0.01) in both turkey lines. The genetic correlations between walking ability and the other evaluated traits ranged from -0.02 to -0.78, with leg defects exhibiting the strongest negative correlation with walking ability. In the female line, 31 SNPs were associated with walking ability and overlapped with 116 genes. These positional genes are linked to 6 gene ontology (GO) terms. Notably, genes such as CSRP2, DDX1, RHBDL1, SEZ6L, and CTSK are involved in growth, development, locomotion, and bone disorders. GO terms, including fibronectin binding (GO:0001968), peptide cross-linking (GO:0018149), and catabolic process (GO:0009057), are directly linked with mobility. In the male line, 66 markers associated with walking ability were identified and overlapped with 281 genes. These genes are linked to 12 GO terms. Genes such as RB1CC1, TNNI1, MSTN, FN1, SIK3, PADI2, ERBB4, B3GNT2, and BACE1 are associated with cell growth, myostatin development, and disorders. GO terms in the male line are predominantly related to lipid metabolism. In conclusion, walking ability is moderately heritable in both populations. Furthermore, walking ability can be enhanced through targeted genetic selection, emphasizing its relevance to both animal welfare and productivity.

Transcriptome analysis of mRNA and miRNA in the development of LeiZhou goat muscles

The progression of muscle development is a pivotal aspect of animal ontogenesis, where miRNA and mRNA exert substantial influence as prominent players. It is important to understand the molecular mechanisms involved in skeletal muscle development to enhance the quality and yield of meat produced by Leizhou goats. We employed RNA sequencing (RNA-SEQ) technology to generate miRNA-mRNA profiles in Leizhou goats, capturing their developmental progression at 0, 3, and 6 months of age. A total of 977 mRNAs and 174 miRNAs were found to be differentially expressed based on our analysis. Metabolic pathways, calcium signaling pathways, and amino acid synthesis and metabolism were found to be significantly enriched among the differentially expressed mRNA in the enrichment analysis. Meanwhile, we found that among these differentially expressed mRNA, some may be related to muscle development, such as MYL10, RYR3, and CSRP3. Additionally,, we identified five muscle-specific miRNAs (miR-127-3p, miR-133a-3p, miR-193b-3p, miR-365-3p, and miR-381) that consistently exhibited high expression levels across all three stages. These miRNAs work with their target genes (FHL3, SESN1, PACSIN3, LMCD1) to regulate muscle development. Taken together, our findings suggest that several miRNAs and mRNAs are involved in regulating muscle development and cell growth in goats. By uncovering the molecular mechanisms involved in muscle growth and development, these findings contribute valuable knowledge that can inform breeding strategies aimed at enhancing meat yield and quality in Leizhou goats.

Integrating miRNA and full-length transcriptome profiling to elucidate the mechanism of muscle growth in Muscovy ducks reveals key roles for miR-301a-3p/ANKRD1

BACKGROUND

The popularity of Muscovy ducks is attributed not only to their conformation traits but also to their slightly higher content of breast and leg meat, as well as their stronger-tasting meat compared to that of typical domestic ducks. However, there is a lack of comprehensive systematic research on the development of breast muscle in Muscovy ducks. In addition, since the number of skeletal muscle myofibers is established during the embryonic period, this study conducted a full-length transcriptome sequencing and microRNA sequencing of the breast muscle. Muscovy ducks at four developmental stages, namely Embryonic Day 21 (E21), Embryonic Day 27 (E27), Hatching Day (D0), and Post-hatching Day 7 (D7), were used to isolate total RNA for analysis.

RESULTS

A total of 68,161 genes and 472 mature microRNAs were identified. In order to uncover deeper insights into the regulation of mRNA by miRNAs, we conducted an integration of the differentially expressed miRNAs (known as DEMs) with the differentially expressed genes (referred to as DEGs) across various developmental stages. This integration allowed us to make predictions regarding the interactions between miRNAs and mRNA. Through this analysis, we identified a total of 274 DEGs that may serve as potential targets for the 68 DEMs. In the predicted miRNA‒mRNA interaction networks, let-7b, miR-133a-3p, miR-301a-3p, and miR-338-3p were the hub miRNAs. In addition, multiple DEMs also showed predicted target relationships with the DEGs associated with skeletal system development. These identified DEGs and DEMs as well as their predicted interaction networks involved in the regulation of energy homeostasis and muscle development were most likely to play critical roles in facilitating the embryo-to-hatchling transition. A candidate miRNA, miR-301a-3p, exhibited increased expression during the differentiation of satellite cells and was downregulated in the breast muscle tissues of Muscovy ducks at E21 compared to E27. A dual-luciferase reporter assay suggested that the ANKRD1 gene, which encodes a transcription factor, is a direct target of miR-301a-3p.

CONCLUSIONS

miR-301a-3p suppressed the posttranscriptional activity of ANKRD1, which is an activator of satellite cell proliferation, as determined with gain- and loss-of-function experiments. miR-301a-3p functions as an inducer of myogenesis by targeting the ANKRD1 gene in Muscovy ducks. These results provide novel insights into the early developmental process of black Muscovy breast muscles and will improve understanding of the underlying molecular mechanisms.

A novel gene-trap line reveals the dynamic patterns and essential roles of cysteine and glycine-rich protein 3 in zebrafish heart development and regeneration

Mutations in cysteine and glycine-rich protein 3 (CSRP3)/muscle LIM protein (MLP), a key regulator of striated muscle function, have been linked to hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) in patients. However, the roles of CSRP3 in heart development and regeneration are not completely understood. In this study, we characterized a novel zebrafish gene-trap line, gSAIzGFFM218A, which harbors an insertion in the csrp3 genomic locus, heterozygous fish served as a csrp3 expression reporter line and homozygous fish served as a csrp3 mutant line. We discovered that csrp3 is specifically expressed in larval ventricular cardiomyocytes (CMs) and that csrp3 deficiency leads to excessive trabeculation, a common feature of CSRP3-related HCM and DCM. We further revealed that csrp3 expression increased in response to different cardiac injuries and was regulated by several signaling pathways vital for heart regeneration. Csrp3 deficiency impeded zebrafish heart regeneration by impairing CM dedifferentiation, hindering sarcomere reassembly, and reducing CM proliferation while aggravating apoptosis. Csrp3 overexpression promoted CM proliferation after injury and ameliorated the impairment of ventricle regeneration caused by pharmacological inhibition of multiple signaling pathways. Our study highlights the critical role of Csrp3 in both zebrafish heart development and regeneration, and provides a valuable animal model for further functional exploration that will shed light on the molecular pathogenesis of CSRP3-related human cardiac diseases.

Betaine attenuates age-related suppression in autophagy via Mettl21c/p97/VCP axis to delay muscle loss

Age-related impairment of autophagy accelerates muscle loss and lead to sarcopenia. Betaine can delay muscle loss as a dietary methyl donor via increasing S-adenosyl-L-methionine (SAM, a crucial metabolite for autophagy regulation) in methionion cycle. However, whether betaine can regulate autophagy level to attenuate degeneration in aging muscle remains unclear. Herein, male C57BL/6J young mice (YOU, 2-month-old), old mice (OLD, 15-month-old), and 2%-betaine-treated old mice (BET, 15-month-old) were employed and raised for 12 weeks. All mice underwent body composition examination and grip strength test before being sacrificed. Betaine alleviated age-related decline in muscle mass and strength. Meanwhile, betaine preserved the expression autophagy markers (Atg5, Atg7, LC3-II, and Beclin1) both at transcriptional and translational level during the aging process. RNA-sequencing results generated from mice gastrocnemius muscle found Mettl21c, a SAM-dependent autophagy-regulating methyltransferase, was significantly higher expressed in BET and YOU group. Results were further validated by qPCR and western bloting. In vitro, C2C12 cells with or without Mettl21c RNA interference were treated different concentration of betaine (0 mM, 10 mM) under methionine-starved condition. Compared with control group, betaine upregulated autophagy markers expression and autophagy flux. By increasing the SAM level, betaine facilitated trimethylation of p97 (Mettl21c downstream effector) into valosin-containing protein (VCP). Increased VCP promoted autophagic turnover of cellular components, ATP production, and cell differentiation. Knock-down of Metthl21c dismissed improvements mentioned above. Collectively, betaine could enhance aged skeletal muscle autophagy level via Mettl21c/p97/VCP axis to delay muscle loss.

High-intensity interval training alleviates exhaustive exercise-induced HSP70-assisted selective autophagy in skeletal muscle

This study was designed to probe the effect of chaperone-assisted selective autophagy (CASA) on the maintenance of proteostasis during exhaustive exercise and uncover the alteration of CASA in muscle fibers with pre-high-intensity interval training (HIIT) intervention-induced muscle adaptation in response to exhaustive exercise. Rats were randomly divided into a control group; an exhaustive exercise group; and an HIIT + exhaustive exercise group. Results show myofibril damage and BiP levels were increased after exhaustive exercise, and the levels of the HSP70, BAG3, ubiquitin, autophagy-related proteins, and their interactions were increased. HIIT intervention before exhaustive exercise could decrease myofibril injury and BiP levels, accompanied by down-regulation of HSP70/BAG3 complex and selective autophagy. In conclusion, exhaustive exercise promotes CASA to clear protein aggregation for keeping proteostasis in muscle fibers; pre-HIIT intervention improves myofibril injury and unfold protein response caused by exhaustive exercise, which might contribute to inhibit the augmentation of CASA.

Native lamin A/C proteomes and novel partners from heart and skeletal muscle in a mouse chronic inflammation model of human frailty

Clinical frailty affects ∼10% of people over age 65 and is studied in a chronically inflamed (Interleukin-10 knockout; "IL10-KO") mouse model. Frailty phenotypes overlap the spectrum of diseases ("laminopathies") caused by mutations in LMNA. LMNA encodes nuclear intermediate filament proteins lamin A and lamin C ("lamin A/C"), important for tissue-specific signaling, metabolism and chromatin regulation. We hypothesized that wildtype lamin A/C associations with tissue-specific partners are perturbed by chronic inflammation, potentially contributing to dysfunction in frailty. To test this idea we immunoprecipitated native lamin A/C and associated proteins from skeletal muscle, hearts and brains of old (21-22 months) IL10-KO versus control C57Bl/6 female mice, and labeled with Tandem Mass Tags for identification and quantitation by mass spectrometry. We identified 502 candidate lamin-binding proteins from skeletal muscle, and 340 from heart, including 62 proteins identified in both tissues. Candidates included frailty phenotype-relevant proteins Perm1 and Fam210a, and nuclear membrane protein Tmem38a, required for muscle-specific genome organization. These and most other candidates were unaffected by IL10-KO, but still important as potential lamin A/C-binding proteins in native heart or muscle. A subset of candidates (21 in skeletal muscle, 30 in heart) showed significantly different lamin A/C-association in an IL10-KO tissue (p < 0.05), including AldoA and Gins3 affected in heart, and Lmcd1 and Fabp4 affected in skeletal muscle. To screen for binding, eleven candidates plus prelamin A and emerin controls were arrayed as synthetic 20-mer peptides (7-residue stagger) and incubated with recombinant purified lamin A "tail" residues 385-646 under relatively stringent conditions. We detected strong lamin A binding to peptides solvent exposed in Lmcd1, AldoA, Perm1, and Tmem38a, and plausible binding to Csrp3 (muscle LIM protein). These results validated both proteomes as sources for native lamin A/C-binding proteins in heart and muscle, identified four candidate genes for Emery-Dreifuss muscular dystrophy (CSRP3, LMCD1, ALDOA, and PERM1), support a lamin A-interactive molecular role for Tmem38A, and supported the hypothesis that lamin A/C interactions with at least two partners (AldoA in heart, transcription factor Lmcd1 in muscle) are altered in the IL10-KO model of frailty.

Transcriptome analysis of the gene expression of M. iliotibialis lateralis affected by dietary methionine restriction

Introduction: Methionine (Met) is an important amino acid related to the development of skeletal muscle. This study investigated the effects of dietary Met restriction on the gene expression of M. iliotibialis lateralis. Methods: A total of 84 day-old broiler chicks (Zhuanghe Dagu) with a similar initial body weight (207.62 ± 8.54 g) were used in this study. All birds were divided into two groups (CON; L-Met) based on the initial body weight. Each group consisted of six replicates with seven birds per replicate. The experimental period was 63 days (phase 1, days 1-21; phase 2, days 22-63). According to the nutritional requirements of Zhuanghe Dagu chickens, we provided a basal diet (0.39% Met levels during phase 1 and 0.35% Met levels during phase 2, as-fed basis) to the birds in the CON group, while we provided a Met-restricted diet (0.31% Met levels during phase 1 and 0.28% Met levels during phase 2, as-fed basis) to the birds in the L-Met group. The growth performance of broiler chicks and their M. iliotibialis lateralis development parameters were measured on days 21 and 63. Results and Discussion: In this study, dietary Met restriction did not affect the growth performance of broiler chicks but hindered the development of M. iliotibialis lateralis at both sampling timepoints. On the final day, three birds selected from each group (three from CON and three from L-Met) were used to obtain M. iliotibialis lateralis samples from leg muscle for further transcriptome analysis. Transcriptome analysis revealed that dietary Met restriction significantly upregulated 247 differentially expressed genes (DEGs) and downregulated 173 DEGs. Additionally, DEGs were mainly enriched in 10 pathways. Among DEGs, we observed that dietary Met restriction downregulated the expression of CSRP3, KY, FHL1, LMCD1, and MYOZ2 in M. iliotibialis lateralis. Therefore, we considered that dietary Met restriction had negative effects on the development of M. iliotibialis lateralis, and CSRP3, KY, FHL1, LMCD1, and MYOZ2 may serve as potential functional genes involved in this process.

Towards the Identification of Biomarkers for Muscle Function Improvement in Myotonic Dystrophy Type 1

BACKGROUND

Myotonic dystrophy type 1 (DM1) is the most common muscular dystrophy in adults. In DM1 patients, skeletal muscle is severely impaired, even atrophied and patients experience a progressive decrease in maximum strength. Strength training for these individuals can improve their muscle function and mass, however, the biological processes involved in these improvements remain unknown.

OBJECTIVE

This exploratory study aims at identifying the proteomic biomarkers and variables associated with the muscle proteome changes induced by training in DM1 individuals.

METHODS

An ion library was developed from liquid chromatography-tandem mass spectrometry proteomic analyses of Vastus Lateralis muscle biopsies collected in 11 individuals with DM1 pre-and post-training.

RESULTS

The proteomic analysis showed that the levels of 44 proteins were significantly modulated. A literature review (PubMed, UniProt, PANTHER, REACTOME) classified these proteins into biological sub-classes linked to training-induced response, including immunity, energy metabolism, apoptosis, insulin signaling, myogenesis and muscle contraction. Linear models identified key variables explaining the proteome modulation, including atrophy and hypertrophy factors. Finally, six proteins of interest involved in myogenesis, muscle contraction and insulin signaling were identified: calpain-3 (CAN3; Muscle development, positive regulation of satellite cell activation), 14-3-3 protein epsilon (1433E; Insulin/Insulin-like growth factor, PI3K/Akt signaling), myosin-binding protein H (MYBPH; Regulation of striated muscle contraction), four and a half LIM domains protein 3 (FHL3; Muscle organ development), filamin-C (FLNC; Muscle fiber development) and Cysteine and glycine-rich protein 3 (CSRP3).

CONCLUSION

These findings may lead to the identification for DM1 individuals of novel muscle biomarkers for clinical improvement induced by rehabilitation, which could eventually be used in combination with a targeted pharmaceutical approach to improving muscle function, but further studies are needed to confirm those results.

Intra-Amniotic Administration-An Emerging Method to Investigate Necrotizing Enterocolitis, In Vivo (Gallus gallus)

Necrotizing enterocolitis (NEC) is a severe gastrointestinal disease in premature infants and a leading cause of death in neonates (1-7% in the US). NEC is caused by opportunistic bacteria, which cause gut dysbiosis and inflammation and ultimately result in intestinal necrosis. Previous studies have utilized the rodent and pig models to mimic NEC, whereas the current study uses the in vivo (Gallus gallus) intra-amniotic administration approach to investigate NEC. On incubation day 17, broiler chicken (Gallus gallus) viable embryos were injected intra-amniotically with 1 mL dextran sodium sulfate (DSS) in H₂O. Four treatment groups (0.1%, 0.25%, 0.5%, and 0.75% DSS) and two controls (H₂O/non-injected controls) were administered. We observed a significant increase in intestinal permeability and negative intestinal morphological changes, specifically, decreased villus surface area and goblet cell diameter in the 0.50% and 0.75% DSS groups. Furthermore, there was a significant increase in pathogenic bacterial (E. coli spp. and Klebsiella spp.) abundances in the 0.75% DSS group compared to the control groups, demonstrating cecal microbiota dysbiosis. These results demonstrate significant physiopathology of NEC and negative bacterial-host interactions within a premature gastrointestinal system. Our present study demonstrates a novel model of NEC through intra-amniotic administration to study the effects of NEC on intestinal functionality, morphology, and gut microbiota in vivo.

Profiling and Functional Analysis of mRNAs during Skeletal Muscle Differentiation in Goats

Skeletal myogenesis is a complicated biological event that involves a succession of tightly controlled gene expressions. In order to identify novel regulators of this process, we performed mRNA-Seq studies of goat skeletal muscle satellite cells (MuSCs) cultured under proliferation (GM) and differentiation (DM1/DM5) conditions. A total of 19,871 goat genes were expressed during these stages, 198 of which represented novel transcripts. Notably, in pairwise comparisons at the different stages, 2551 differentially expressed genes (DEGs) were identified (p < 0.05), including 1560 in GM vs. DM1, 1597 in GM vs. DM5, and 959 in DM1 vs. DM5 DEGs. The time-series expression profile analysis clustered the DEGs into eight gene groups, three of which had significantly upregulated and downregulated patterns (p < 0.05). Functional enrichment analysis showed that DEGs were enriched for essential biological processes such as muscle structure development, muscle contraction, muscle cell development, striated muscle cell differentiation, and myofibril assembly, and were involved in pathways such as the MAPK, Wnt and PPAR signaling pathways. Moreover, the expression of eight DEGs (MYL2, DES, MYOG, FAP, PLK2, ADAM, WWC1, and PRDX1) was validated. These findings offer novel insights into the transcriptional regulation of skeletal myogenesis in goats.

Differential Effects of 25-Hydroxyvitamin D3 versus 1α 25-Dihydroxyvitamin D3 on Adipose Tissue Browning in CKD-Associated Cachexia

Patients with chronic kidney disease (CKD) often have low serum concentrations of 25(OH)D3 and 1,25(OH)2D3. We investigated the differential effects of 25(OH)D3 versus 1,25(OH)2D3 repletion in mice with surgically induced CKD. Intraperitoneal supplementation of 25(OH)D3 (75 μg/kg/day) or 1,25(OH)2D3 (60 ng/kg/day) for 6 weeks normalized serum 25(OH)D3 or 1,25(OH)2D3 concentrations in CKD mice, respectively. Repletion of 25(OH)D3 normalized appetite, significantly improved weight gain, increased fat and lean mass content and in vivo muscle function, as well as attenuated elevated resting metabolic rate relative to repletion of 1,25(OH)2D3 in CKD mice. Repletion of 25(OH)D3 in CKD mice attenuated adipose tissue browning as well as ameliorated perturbations of energy homeostasis in adipose tissue and skeletal muscle, whereas repletion of 1,25(OH)2D3 did not. Significant improvement of muscle fiber size and normalization of fat infiltration of gastrocnemius was apparent with repletion of 25(OH)D3 but not with 1,25(OH)2D3 in CKD mice. This was accompanied by attenuation of the aberrant gene expression of muscle mass regulatory signaling, molecular pathways related to muscle fibrosis as well as muscle expression profile associated with skeletal muscle wasting in CKD mice. Our findings provide evidence that repletion of 25(OH)D3 exerts metabolic advantages over repletion of 1,25(OH)2D3 by attenuating adipose tissue browning and muscle wasting in CKD mice.

Targeting interleukin-1 for reversing fat browning and muscle wasting in infantile nephropathic cystinosis

BACKGROUND

Ctns-/- mice, a mouse model of infantile nephropathic cystinosis, exhibit hypermetabolism with adipose tissue browning and profound muscle wasting. Inflammatory cytokines such as interleukin (IL)-1 trigger inflammatory cascades and may be an important cause for cachexia. We employed genetic and pharmacological approaches to investigate the effects of IL-1 blockade in Ctns-/- mice.

METHODS

We generated Ctns-/- Il1β-/- mice, and we treated Ctns-/- and wild-type control mice with IL-1 receptor antagonist, anakinra (2.5 mg/kg/day, IP) or saline as vehicle for 6 weeks. In each of these mouse lines, we characterized the cachexia phenotype consisting of anorexia, loss of weight, fat mass and lean mass, elevation of metabolic rate, and reduced in vivo muscle function (rotarod activity and grip strength). We quantitated energy homeostasis by measuring the protein content of uncoupling proteins (UCPs) and adenosine triphosphate in adipose tissue and skeletal muscle. We measured skeletal muscle fiber area and intramuscular fatty infiltration. We also studied expression of molecules regulating adipose tissue browning and muscle mass metabolism. Finally, we evaluated the impact of anakinra on the muscle transcriptome in Ctns-/- mice.

RESULTS

Skeletal muscle expression of IL-1β was significantly elevated in Ctns-/- mice relative to wild-type control mice. Cachexia was completely normalized in Ctns-/- Il1β-/- mice relative to Ctns-/- mice. We showed that anakinra attenuated the cachexia phenotype in Ctns-/- mice. Anakinra normalized UCPs and adenosine triphosphate content of adipose tissue and muscle in Ctns-/- mice. Anakinra attenuated aberrant expression of beige adipose cell biomarkers (UCP-1, CD137, Tmem26, and Tbx1) and molecules implicated in adipocyte tissue browning (Cox2/Pgf2α, Tlr2, Myd88, and Traf6) in inguinal white adipose tissue in Ctns-/- mice. Moreover, anakinra normalized gastrocnemius weight and fiber size and attenuated muscle fat infiltration in Ctns-/- mice. This was accompanied by correction of the increased muscle wasting signalling pathways (increased protein content of ERK1/2, JNK, p38 MAPK, and nuclear factor-κB p65 and mRNA expression of Atrogin-1 and Myostatin) and the decreased myogenesis process (decreased mRNA expression of MyoD and Myogenin) in the gastrocnemius muscle of Ctns-/- mice. Previously, we identified the top 20 differentially expressed skeletal muscle genes in Ctns-/- mice by RNAseq. Aberrant expression of these 20 genes have been implicated in muscle wasting, increased energy expenditure, and lipolysis. We showed that anakinra attenuated 12 of those top 20 differentially expressed muscle genes in Ctns-/- mice.

CONCLUSIONS

Anakinra may provide a targeted novel therapy for patients with infantile nephropathic cystinosis.

CSRP3, p.Arg122*, is responsible for hypertrophic cardiomyopathy in a Chinese family

BACKGROUND

Hypertrophic cardiomyopathy (HCM) is a hereditary disease manifested by a thickened ventricular wall. Cysteine and glycine-rich protein 3 (CSRP3), the gene encoding muscle LIM protein, is important for initiating hypertrophic gene expression. The mutation of CSRP3 causes dilated cardiomyopathy or HCM.

METHODS

In the present study, we enrolled a Chinese family with HCM across three generations. Whole-exome sequencing (WES) was performed in the proband to detect the candidate genes of the family. Sanger sequencing was performed for mutational analysis and confirmation of cosegregation.

RESULTS

Through histopathological and imaging examinations, an obvious left ventricular hypertrophy was found in the proband. After WES data filtering, bioinformatic prediction and co-segregation analysis, a nonsense mutation (NM_003476.5:c.364C>T; NP_003467.1:p.Arg122*) of CSRP3 was identified in this family. This variant was predicted to be disease-causing and resulted in a truncated protein.

CONCLUSIONS

This is the first HCM family case of CSRP3 (p.Arg122*) variation in Asia. The finding here not only contributes to the genetic diagnosis and counseling of the family, but also provides a new case with detailed phenotypes that may be caused by the CSRP3 variant.

A Leptin Receptor Antagonist Attenuates Adipose Tissue Browning and Muscle Wasting in Infantile Nephropathic Cystinosis-Associated Cachexia

Mice lacking the functional cystinosin gene (Ctns-/-), a model of infantile nephropathic cystinosis (INC), exhibit the cachexia phenotype with adipose tissue browning and muscle wasting. Elevated leptin signaling is an important cause of chronic kidney disease-associated cachexia. The pegylated leptin receptor antagonist (PLA) binds to but does not activate the leptin receptor. We tested the efficacy of this PLA in Ctns-/- mice. We treated 12-month-old Ctns-/- mice and control mice with PLA (7 mg/kg/day, IP) or saline as a vehicle for 28 days. PLA normalized food intake and weight gain, increased fat and lean mass, decreased metabolic rate and improved muscle function. It also attenuated perturbations of energy homeostasis in adipose tissue and muscle in Ctns-/- mice. PLA attenuated adipose tissue browning in Ctns-/- mice. PLA increased gastrocnemius weight and fiber size as well as attenuated muscle fat infiltration in Ctns-/- mice. This was accompanied by correcting the increased expression of muscle wasting signaling while promoting the decreased expression of myogenesis in gastrocnemius of Ctns-/- mice. PLA attenuated aberrant expressed muscle genes that have been associated with muscle atrophy, increased energy expenditure and lipolysis in Ctns-/- mice. Leptin antagonism may represent a viable therapeutic strategy for adipose tissue browning and muscle wasting in INC.

The role of IL-1 in adipose browning and muscle wasting in CKD-associated cachexia

Cytokines such as IL-6, TNF-α and IL-1β trigger inflammatory cascades which may play a role in the pathogenesis of chronic kidney disease (CKD)-associated cachexia. CKD was induced by 5/6 nephrectomy in mice. We studied energy homeostasis in Il1β-/-/CKD, Il6-/-/CKD and Tnfα-/-/CKD mice and compared with wild type (WT)/CKD controls. Parameters of cachexia phenotype were completely normalized in Il1β-/-/CKD mice but were only partially rescued in Il6-/-/CKD and Tnfα-/-/CKD mice. We tested the effects of anakinra, an IL-1 receptor antagonist, on CKD-associated cachexia. WT/CKD mice were treated with anakinra (2.5 mg/kg/day, IP) or saline for 6 weeks and compared with WT/Sham controls. Anakinra normalized food intake and weight gain, fat and lean mass content, metabolic rate and muscle function, and also attenuated molecular perturbations of energy homeostasis in adipose tissue and muscle in WT/CKD mice. Anakinra decreased serum and muscle expression of IL-6, TNF-α and IL-1β in WT/CKD mice. Anakinra attenuated browning of white adipose tissue in WT/CKD mice. Moreover, anakinra normalized gastrocnemius weight and fiber size as well as attenuated muscle fat infiltration in WT/CKD mice. This was accompanied by correcting the increased muscle wasting signaling pathways while promoting the decreased myogenesis process in gastrocnemius of WT/CKD mice. We performed qPCR analysis for the top 20 differentially expressed muscle genes previously identified via RNAseq analysis in WT/CKD mice versus controls. Importantly, 17 differentially expressed muscle genes were attenuated in anakinra treated WT/CKD mice. In conclusion, IL-1 receptor antagonism may represent a novel targeted treatment for adipose tissue browning and muscle wasting in CKD.

Characterization and Comparative Transcriptomic Analysis of Skeletal Muscle in Pekin Duck at Different Growth Stages Using RNA-Seq

Simple Summary

Skeletal muscle is an important tissue and its development is strictly regulated by genes. In this study, in order to understand the muscle-related gene expression in Pekin duck, RNA-seq was performed to analyze and compare skeletal muscle at different growth stages. Alternative splicing, single nucleotide polymorphisms and insertion–deletions were detected, and 299 novel genes were discovered. MYL4, IGF2BP1, CSRP3, SPP1, KLHL31, LAMB2, LAMA2, ITGB1 and OPN played crucial roles in skeletal muscle development. Oxidative phosphorylation, ECM-receptor interaction, focal adhesion, carbon metabolism, and biosynthesis of amino acids participated in the regulation of skeletal muscle development in Pekin duck. This study provides an important reference for revealing the developmental mechanisms of pectoral and leg muscles in duck.

Abstract

Skeletal muscle, accounting for approximately 50% of body weight, is the largest and most important tissue. In this study, the gene expression profiles and pathways in skeletal muscle of Pekin duck were investigated and compared at embryonic day 17, 21, and 27 and postnatally at 6 months of age. An average of 49,555,936 reads in each sample was obtained from the transcriptome libraries. Over 70.0% of alternative splicing (AS) in each sample was mainly alternative 5′ first exon (transcription start site)—the first exon splicing (TSS) and alternative 3′ last exon (transcription terminal site)—the last exon splicing (TTS), indicating that TSS and TTS were the most common AS event in Pekin ducks, and these AS events were closely related to the regulation of muscle development at different growth stages. The results provided a valuable genomic resource for selective breeding and functional studies of genes. A total of 299 novel genes with ≥2 exons were obtained. There were 294 to 2806 differentially expressed genes (DEGs) in each pairwise comparison of Pekin duck. Notably, 90 DEGs in breast muscle and 9 DEGs in leg muscle were co-expressed at all developmental points. DEGs were validated by qPCR analysis, which confirmed the tendency of the expression. DEGs related to muscle development were involved in biological processes such as “endodermal cell differentiation”, “muscle cell cellular homeostasis”, “skeletal muscle tissue growth” and “skeletal muscle cell differentiation”, and were involved in pathways such as oxidative phosphorylation, ECM-receptor (extracellular matrix receptor) interaction, focal adhesion, carbon metabolism, and biosynthesis of amino acids. Some DEGs, including MYL4, IGF2BP1, CSRP3, SPP1 and KLHL31, as well as LAMB2, LAMA2, ITGB1 and OPN, played crucial roles in muscle growth and development. This study provides valuable information about the expression profile of mRNAs and pathways from duck skeletal muscle at different growth stages, and further functional study of these mRNAs and pathways could provide new ideas for studying the molecular networks of growth and development in duck skeletal muscle.

An Analysis of Differentially Expressed Coding and Long Non-Coding RNAs in Multiple Models of Skeletal Muscle Atrophy

The loss of skeletal muscle mass (muscle atrophy or wasting) caused by aging, diseases, and injury decreases quality of life, survival rates, and healthy life expectancy in humans. Although long non-coding RNAs (lncRNAs) have been implicated in skeletal muscle formation and differentiation, their precise roles in muscle atrophy remain unclear. In this study, we used RNA-sequencing (RNA-Seq) to examine changes in the expression of lncRNAs in four muscle atrophy conditions (denervation, casting, fasting, and cancer cachexia) in mice. We successfully identified 33 annotated lncRNAs and 18 novel lncRNAs with common expression changes in all four muscle atrophy conditions. Furthermore, an analysis of lncRNA–mRNA correlations revealed that several lncRNAs affected small molecule biosynthetic processes during muscle atrophy. These results provide novel insights into the lncRNA-mediated regulatory mechanism underlying muscle atrophy and may be useful for the identification of promising therapeutic targets.

Identification of transcriptomic characteristics during nasal capsular contracture progression using RNA deep sequencing

Nasal capsular contracture is a prevalent complication commonly observed after rhinoplasty. However, the mechanism underlying the pathogenesis of nasal capsular contracture is largely unclear compared to that of breast capsular contracture. This study aimed to identify the key genes implicated in nasal capsular contracture progression using RNA deep sequencing (RNA-seq). Biopsy samples were taken from Grade II to Grade IV nasal fibrous capsular tissues. The former is regarded as the relatively normal tissues and thus was set as control group, while the latter was treated as pathological group. Results from RNA-seq underwent GO enrichment and KEGG pathway analysis and subsequent verification by quantitative reverse transcriptase polymerase chain reaction and western blot assays. RNA-seq analysis showed that 3149 genes were up-regulated and 3131 genes in pathological groups compared with controls. The top 30 up-regulated genes included many chemokines (e.g., CCL18, CCL13, CCL17 and CCL8), matrix metallopeptidases (e.g., MMP9 and MMP12) and integrin proteins (e.g., ITGAM and ITGB2). GO enrichment analysis demonstrated that the up-regulated genes affected various immune functions, including immune system process, cell activation, leukocyte activation, defence response and positive regulation of immune. The down-regulated gene primary influenced muscle development and functions as well as metabolic processes. In summary, this study reveal that abnormal changes of immune functions, muscle develop and metabolic processes are probably implicated in the pathogenesis of nasal capsular contracture.

Transcriptomics analysis for the identification of potential age-related genes and cells associated with three major urogenital cancers

Age is one of the most important risk factors of the occurrence for tumor patients. The majority of patients with urogenital cancers are the elderly, whose clinical characteristics are greatly affected by age and ageing. Our study aimed to explore age-related genes, cells, and biological changes in three common urogenital cancers via integrative bioinformatics analysis. First, mRNA (count format) and clinical data for bladder cancer, prostate cancer and renal cell carcinoma were downloaded from the Cancer Genome Atlas (TCGA). Through the comparison of clinicopathological characteristics, genes expression and cells infiltration between the old group and the young group, it was found that the clinical characteristics, genes and cells in the tumor microenvironment of different ages were quite different. And 4 key cells, 14 hub genes and some potential pathways were identified and considered as important factors. More importantly, we analyzed the differential landscape of the genes and cells from different perspectives, and confirmed its importance. In conclusion, we identified genes and cell types associated with age-related changes in the tumour microenvironment in urogenital cancer patients. These genes and cell types may play a critical role in the age-associated differences in clinicopathological characteristics among urogenital cancers, thus providing a link between ageing and cancer occurrence. The findings of this study may pave the way for the development of age-tailored approaches to treat cancer and other age-related diseases.

Master Regulators of Muscle Atrophy: Role of Costamere Components

The loss of muscle mass and force characterizes muscle atrophy in several different conditions, which share the expression of atrogenes and the activation of their transcriptional regulators. However, attempts to antagonize muscle atrophy development in different experimental contexts by targeting contributors to the atrogene pathway showed partial effects in most cases. Other master regulators might independently contribute to muscle atrophy, as suggested by our recent evidence about the co-requirement of the muscle-specific chaperone protein melusin to inhibit unloading muscle atrophy development. Furthermore, melusin and other muscle mass regulators, such as nNOS, belong to costameres, the macromolecular complexes that connect sarcolemma to myofibrils and to the extracellular matrix, in correspondence with specific sarcomeric sites. Costameres sense a mechanical load and transduce it both as lateral force and biochemical signals. Recent evidence further broadens this classic view, by revealing the crucial participation of costameres in a sarcolemmal “signaling hub” integrating mechanical and humoral stimuli, where mechanical signals are coupled with insulin and/or insulin-like growth factor stimulation to regulate muscle mass. Therefore, this review aims to enucleate available evidence concerning the early involvement of costamere components and additional putative master regulators in the development of major types of muscle atrophy.

Prospect of early vascular tone and satellite cell modulations on white striping muscle myopathy

Polyphasic myodegeneration potentially causes severe physiological and metabolic disorders in the breast muscle of fast-growing broiler chickens. To date, the etiology of recent muscle myopathies, such as the white striping (WS) phenotype, is still unknown. White striping–affected breast meats compromise the water holding capacity and predispose muscle to poor vascular tone, leading to the deterioration of meat qualities. Herein, this review article provides insight on the complexities around chicken breast myopathies: (i) the etiologies of WS occurrence in chicken; (ii) the metabolic changes that occur in WS defect in pectoralis major; and (iii) the interactions between breast muscle physiology and vascular tone. It also addressed the effects of nutritional supplements on muscle myopathies on chicken breast meats. Moreover, the review explored breast muscle biology focusing on the early preparation of satellite and vascular cells in fast-growth chicken breeds. Transcriptomics and histological analyses revealed poor vascularity in breast muscle of fast growth chickens. Thus, we suggest in ovo feeding of nutrients promoting vascularization and satellite cells replenishment as a potential strategy to enhance endothelium-derived nitric oxide availability to promote vascularization in the pectoralis major muscle region.

Isoquercitrin Delays Denervated Soleus Muscle Atrophy by Inhibiting Oxidative Stress and Inflammation

Although denervated muscle atrophy is common, the underlying molecular mechanism remains unelucidated. We have previously found that oxidative stress and inflammatory response may be early events that trigger denervated muscle atrophy. Isoquercitrin is a biologically active flavonoid with antioxidative and anti-inflammatory properties. The present study investigated the effect of isoquercitrin on denervated soleus muscle atrophy and its possible molecular mechanisms. We found that isoquercitrin was effective in alleviating soleus muscle mass loss following denervation in a dose-dependent manner. Isoquercitrin demonstrated the optimal protective effect at 20 mg/kg/d, which was the dose used in subsequent experiments. To further explore the protective effect of isoquercitrin on denervated soleus muscle atrophy, we analyzed muscle proteolysis via the ubiquitin-proteasome pathway, mitophagy, and muscle fiber type conversion. Isoquercitrin significantly inhibited the denervation-induced overexpression of two muscle-specific ubiquitin ligases—muscle RING finger 1 (MuRF1) and muscle atrophy F-box (MAFbx), and reduced the degradation of myosin heavy chains (MyHCs) in the target muscle. Following isoquercitrin treatment, mitochondrial vacuolation and autophagy were inhibited, as evidenced by reduced level of autophagy-related proteins (ATG7, BNIP3, LC3B, and PINK1); slow-to-fast fiber type conversion in the target muscle was delayed via triggering expression of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α); and the production of reactive oxygen species (ROS) in the target muscle was reduced, which might be associated with the upregulation of antioxidant factors (SOD1, SOD2, NRF2, NQO1, and HO1) and the downregulation of ROS production-related factors (Nox2, Nox4, and DUOX1). Furthermore, isoquercitrin treatment reduced the levels of inflammatory factors—interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α)—in the target muscle and inactivated the JAK/STAT3 signaling pathway. Overall, isoquercitrin may alleviate soleus muscle atrophy and mitophagy and reverse the slow-to-fast fiber type conversion following denervation via inhibition of oxidative stress and inflammatory response. Our study findings enrich the knowledge regarding the molecular regulatory mechanisms of denervated muscle atrophy and provide a scientific basis for isoquercitrin as a protective drug for the prevention and treatment of denervated muscle atrophy.