The Impact of miR-155-5p on Myotube Differentiation: Elucidating Molecular Targets in Skeletal Muscle Disorders

MicroRNAs are small regulatory molecules that control gene expression. An emerging property of muscle miRNAs is the cooperative regulation of transcriptional and epitranscriptional events controlling muscle phenotype. miR-155 has been related to muscular dystrophy and muscle cell atrophy. However, the function of miR-155 and its molecular targets in muscular dystrophies remain poorly understood. Through in silico and in vitro approaches, we identify distinct transcriptional profiles induced by miR-155-5p in muscle cells. The treated myotubes changed the expression of 359 genes (166 upregulated and 193 downregulated). We reanalyzed muscle transcriptomic data from dystrophin-deficient patients and detected overlap with gene expression patterns in miR-155-treated myotubes. Our analysis indicated that miR-155 regulates a set of transcripts, including Aldh1l, Nek2, Bub1b, Ramp3, Slc16a4, Plce1, Dync1i1, and Nr1h3. Enrichment analysis demonstrates 20 targets involved in metabolism, cell cycle regulation, muscle cell maintenance, and the immune system. Moreover, digital cytometry confirmed a significant increase in M2 macrophages, indicating miR-155's effects on immune response in dystrophic muscles. We highlight a critical miR-155 associated with disease-related pathways in skeletal muscle disorders.

Melatonin enhances cell death and suppresses the metastatic capacity of ovarian cancer cells by attenuating the signaling of multiple kinases

BACKGROUND

Ovarian cancer is a highly aggressive disease that is frequently diagnosed in advanced stages. Melatonin, with its numerous antitumor properties, holds great promise in cancer treatment. Herein, we investigated the effects of melatonin on apoptosis, cell migration, and kinase levels in human ovarian carcinoma SKOV-3 cells and determined whether these effects are mediated by the activation of the MT1 receptor.

METHODS

SKOV-3 cells were exposed to different concentrations of melatonin based on the presence of MT1 receptor, and we also performed specific silencing of the melatonin receptor gene MTNR1A.

RESULTS

Our findings revealed that melatonin reduced cell viability as shown by the MTT assay, and flow cytometry analysis showed increased rates of apoptosis and necrosis in all melatonin-treated cells. Melatonin significantly decreased the migratory and invasive capacities of the cells. Propidium iodide labeling indicated that melatonin induced cell cycle arrest by reducing DNA content in the S and G2/M phases in SKOV-3 cells. Additionally, the levels of AKT, ERK1/2, JNK, CREB, p70S6K, STAT3/5, and p38 MAP kinase involved in cell survival, proliferation, motility, and stress responses were depressed by melatonin and further reduced after MT1 knockdown. These molecules were found to be associated with lower overall survival in ovarian cancer patients.

CONCLUSIONS

Melatonin had obvious oncostatic actions on ovarian cancer cells, and MT1 receptor knockdown intensified its antitumor effect. The inhibition of the MT1 receptor resulted in a substantial reduction in the migratory and invasive capacities of the cells, suggesting its potential as a therapeutic target for the treatment of ovarian cancer.

The Transcriptomic Landscape of Age-Induced Changes in Human Visceral Fat and the Predicted Omentum-Liver Connectome in Males

Aging causes alterations in body composition. Specifically, visceral fat mass increases with age and is associated with age-related diseases. The pathogenic potential of visceral fat accumulation has been associated with its anatomical location and metabolic activity. Visceral fat may control systemic metabolism by secreting molecules that act in distal tissues, mainly the liver, through the portal vein. Currently, little is known about age-related changes in visceral fat in humans. Aiming to identify molecular and cellular changes occurring with aging in the visceral fat of humans, we analyzed publicly available transcriptomic data of 355 omentum samples from the Genotype-Tissue Expression portal (GTEx) of 20-79-year-old males and females. We identified the functional enrichment of genes associated with aging, inferred age-related changes in visceral fat cellularity by deconvolution analysis, profiled the senescence-associated secretory phenotype of visceral adipose tissue, and predicted the connectivity of the age-induced visceral fat secretome with the liver. We demonstrate that age induces alterations in visceral fat cellularity, synchronous to changes in metabolic pathways and a shift toward a pro-inflammatory secretory phenotype. Furthermore, our approach identified candidates such as ADIPOQ-ADIPOR1/ADIPOR2, FCN2-LPR1, and TF-TFR2 to mediate visceral fat-liver crosstalk in the context of aging. These findings cast light on how alterations in visceral fat with aging contribute to liver dysfunction and age-related disease etiology.

Transcriptomic insight into the hybridization mechanism of the Tambacu, a hybrid from Colossoma macropomum (Tambaqui) and Piaractus mesopotamicus (Pacu)

Interspecific hybrids are highly complex organisms, especially considering aspects related to the organization of genetic material. The diversity of possibilities created by the genetic combination between different species makes it difficult to establish a large-scale analysis methodology. An example of this complexity is Tambacu, an interspecific hybrid of Colossoma macropomum (Tambaqui) and Piaractus mesopotamicus (Pacu). Either genotype represents an essential role in South American aquaculture. However, despite this importance, the genetic information for these genotypes is still highly scarce in specialized databases. Using RNA-Seq analysis, we characterized the transcriptome of white muscle from Pacu, Tambaqui, and their interspecific hybrid (Tambacu). The sequencing process allowed us to obtain a significant number of reads (approximately 53 billion short reads). A total of annotated contigs were 37,285, 96,738, and 158,709 for Pacu, Tambaqui, and Tambacu. After that, we performed a comparative analysis of the transcriptome of the three genotypes, where we evaluated the differential expression (Tambacu vs Pacu = 11,156, and Tambacu vs Tambaqui = 876) profile of the transcript and the degree of similarity between the nucleotide sequences between the genotypes. We assessed the intensity and pattern of expression across genotypes using differential expression information. Clusterization analysis showed a closer relationship between Tambaqui and Tambacu. Furthermore, digital differential expression analysis selected some target genes related to essential cellular processes to evaluate and validate the expression through the RT-qPCR. The RT-qPCR analysis demonstrated significantly (p < 0.05) elevated expression of the mafbx, foxo1a, and rgcc genes in the hybrid compared to the parents. Likewise, we can observe genes significantly more expressed in Pacu (mtco1 and mylpfa) and mtco2 in Tambaqui. Our results showed that the phenotype presented by Tambacu might be associated with changes in the gene expression profile and not necessarily with an increase in gene variability. Thus, the molecular mechanisms underlying these "hybrid effects" may be related to additive and, in some cases, dominant regulatory interactions between parental alleles that act directly on gene regulation in the hybrid transcripts.

Low muscle mass in lung cancer is associated with an inflammatory and immunosuppressive tumor microenvironment

BACKGROUND

Computed tomographies (CT) are useful for identifying muscle loss in non-small lung cancer (NSCLC) cachectic patients. However, we lack consensus on the best cutoff point for pectoralis muscle loss. We aimed to characterize NSCLC patients based on muscularity, clinical data, and the transcriptional profile from the tumor microenvironment to build a cachexia classification model.

METHODS

We used machine learning to generate a muscle loss prediction model, and the tumor's cellular and transcriptional profile was characterized in patients with low muscularity. First, we measured the pectoralis muscle area (PMA) of 211 treatment-naive NSCLC patients using CT available in The Cancer Imaging Archive. The cutoffs were established using machine learning algorithms (CART and Cutoff Finder) on PMA, clinical, and survival data. We evaluated the prediction model in a validation set (36 NSCLC). Tumor RNA-Seq (GSE103584) was used to profile the transcriptome and cellular composition based on digital cytometry.

RESULTS

CART demonstrated that a lower PMA was associated with a high risk of death (HR = 1.99). Cutoff Finder selected PMA cutoffs separating low-muscularity (LM) patients based on the risk of death (P-value = 0.003; discovery set). The cutoff presented 84% of success in classifying low muscle mass. The high risk of LM patients was also found in the validation set. Tumor RNA-Seq revealed 90 upregulated secretory genes in LM that potentially interact with muscle cell receptors. The LM upregulated genes enriched inflammatory biological processes. Digital cytometry revealed that LM patients presented high proportions of cytotoxic and exhausted CD8+ T cells.

CONCLUSIONS

Our prediction model identified cutoffs that distinguished patients with lower PMA and survival with an inflammatory and immunosuppressive TME enriched with inflammatory factors and CD8+ T cells.

Identification of Novel Genes Associated with Fish Skeletal Muscle Adaptation during Fasting and Refeeding Based on a Meta-Analysis

The regulation of the fish phenotype and muscle growth is influenced by fasting and refeeding periods, which occur in nature and are commonly applied in fish farming. However, the regulators associated with the muscle responses to these manipulations of food availability have not been fully characterized. We aimed to identify novel genes associated with fish skeletal muscle adaptation during fasting and refeeding based on a meta-analysis. Genes related to translational and proliferative machinery were investigated in pacus (Piaractus mesopotamicus) subjected to fasting (four and fifteen days) and refeeding (six hours, three and fifteen days). Our results showed that different fasting and refeeding periods modulate the expression of the genes mtor, rps27a, eef1a2, and cdkn1a. These alterations can indicate the possible protection of the muscle phenotype, in addition to adaptive responses that prioritize energy and substrate savings over cell division, a process regulated by ccnd1. Our study reveals the potential of meta-analysis for the identification of muscle growth regulators and provides new information on muscle responses to fasting and refeeding in fish that are of economic importance to aquaculture.

Single-cell and bulk RNA sequencing reveal ligands and receptors associated with worse overall survival in serous ovarian cancer

Background

Serous ovarian carcinoma is the most frequent histological subgroup of ovarian cancer and the leading cause of death among gynecologic tumors. The tumor microenvironment and cancer-associated fibroblasts (CAFs) have a critical role in the origin and progression of cancer. We comprehensively characterized the crosstalk between CAFs and ovarian cancer cells from malignant fluids to identify specific ligands and receptors mediating intercellular communications and disrupted pathways related to prognosis and therapy response.

Methods

Malignant fluids of serous ovarian cancer, including tumor-derived organoids, CAFs-enriched (eCAFs), and malignant effusion cells (no cultured) paired with normal ovarian tissues, were explored by RNA-sequencing. These data were integrated with single-cell RNA-sequencing data of ascites from ovarian cancer patients. The most relevant ligand and receptor interactions were used to identify differentially expressed genes with prognostic values in ovarian cancer.

Results

CAF ligands and epithelial cancer cell receptors were enriched for PI3K-AKT, focal adhesion, and epithelial-mesenchymal transition signaling pathways. Collagens, MIF, MDK, APP, and laminin were detected as the most significant signaling, and the top ligand-receptor interactions THBS2/THBS3 (CAFs)—CD47 (cancer cells), MDK (CAFs)—NCL/SDC2/SDC4 (cancer cells) as potential therapeutic targets. Interestingly, 34 genes encoding receptors and ligands of the PI3K pathway were associated with the outcome, response to treatment, and overall survival in ovarian cancer. Up-regulated genes from this list consistently predicted a worse overall survival (hazard ratio > 1.0 and log-rank P < 0.05) in two independent validation cohorts.

Conclusions

This study describes critical signaling pathways, ligands, and receptors involved in the communication between CAFs and cancer cells that have prognostic and therapeutic significance in ovarian cancer.

Fibronectin Modulates the Expression of miRNAs in Prostate Cancer Cell Lines

Prostate cancer (PCa) is a significant cause of cancer-related deaths among men and companion animals, such as dogs. However, despite its high mortality and incidence rates, the molecular mechanisms underlying this disease remain to be fully elucidated. Among the many factors involved in prostate carcinogenesis, the extracellular matrix (ECM) plays a crucial role. This ECM in the prostate is composed mainly of collagen fibers, reticular fibers, elastic fibers, proteoglycans and glycoproteins, such as fibronectin. Fibronectin is a glycoprotein whose dysregulation has been implicated in the development of multiple types of cancer, and it has been associated with cell migration, invasion, and metastasis. Furthermore, our research group has previously shown that fibronectin induces transcriptional changes by modulating the expression of protein coding genes in LNCaP cells. However, potential changes at the post-transcriptional level are still not well understood. This study investigated the impact of exposure to fibronectin on the expression of a key class of regulatory RNAs, the microRNAs (miRNAs), in prostate cancer cell lines LNCaP and PC-3. Five mammalian miRNAs (miR-21, miR-29b, miR-125b, miR-221, and miR-222) were differentially expressed after fibronectin exposure in prostate cell lines. The expression profile of hundreds of mRNAs predicted to be targeted by these miRNAs was analyzed using publicly available RNA-Sequencing data (GSE64025, GSE68645, GSE29155). Also, protein-protein interaction networks and enrichment analysis were performed to gain insights into miRNA biological functions. Altogether, these functional analyzes revealed that fibronectin exposure impacts the expression of miRNAs potentially involved in PCa causing changes in critical signaling pathways such as PI3K-AKT, and response to cell division, death, proliferation, and migration. The relationship here demonstrated between fibronectin exposure and altered miRNA expression improves the comprehension of PCa in both men and other animals, such as dogs, which naturally develop prostate cancer.

Prediction of Non-canonical Routes for SARS-CoV-2 Infection in Human Placenta Cells

The SARS-CoV-2 is the causative agent of the COVID-19 pandemic. The data available about COVID-19 during pregnancy have demonstrated placental infection; however, the mechanisms associated with intrauterine transmission of SARS-CoV-2 is still debated. Intriguingly, while canonical SARS-CoV-2 cell entry mediators are expressed at low levels in placental cells, the receptors for viruses that cause congenital infections such as the cytomegalovirus and Zika virus are highly expressed in these cells. Here we analyzed the transcriptional profile (microarray and single-cell RNA-Seq) of proteins potentially interacting with coronaviruses to identify non- canonical mediators of SARS-CoV-2 infection and replication in the placenta. Despite low levels of the canonical cell entry mediators ACE2 and TMPRSS2, we show that cells of the syncytiotrophoblast, villous cytotrophoblast, and extravillous trophoblast co-express high levels of the potential non-canonical cell-entry mediators DPP4 and CTSL. We also found changes in the expression of DAAM1 and PAICS genes during pregnancy, which are translated into proteins also predicted to interact with coronaviruses proteins. These results provide new insight into the interaction between SARS-CoV-2 and host proteins that may act as non-canonical routes for SARS-CoV-2 infection and replication in the placenta cells.

Multidimensional Single-Nuclei RNA-Seq Reconstruction of Adipose Tissue Reveals Adipocyte Plasticity Underlying Thermogenic Response

Adipose tissue has been classified based on its morphology and function as white, brown, or beige/brite. It plays an essential role as a regulator of systemic metabolism through paracrine and endocrine signals. Recently, multiple adipocyte subtypes have been revealed using RNA sequencing technology, going beyond simply defined morphology but also by their cellular origin, adaptation to metabolic stress, and plasticity. Here, we performed an in-depth analysis of publicly available single-nuclei RNAseq from adipose tissue and utilized a workflow template to characterize adipocyte plasticity, heterogeneity, and secretome profiles. The reanalyzed dataset led to the identification of different subtypes of adipocytes including three subpopulations of thermogenic adipocytes, and provided a characterization of distinct transcriptional profiles along the adipocyte trajectory under thermogenic challenges. This study provides a useful resource for further investigations regarding mechanisms related to adipocyte plasticity and trans-differentiation.

Drug Repositioning Based on the Reversal of Gene Expression Signatures Identifies TOP2A as a Therapeutic Target for Rectal Cancer

Rectal cancer is a common disease with high mortality rates and limited therapeutic options. Here we combined the gene expression signatures of rectal cancer patients with the reverse drug-induced gene-expression profiles to identify drug repositioning candidates for cancer therapy. Among the predicted repurposable drugs, topoisomerase II inhibitors (doxorubicin, teniposide, idarubicin, mitoxantrone, and epirubicin) presented a high potential to reverse rectal cancer gene expression signatures. We showed that these drugs effectively reduced the growth of colorectal cancer cell lines closely representing rectal cancer signatures. We also found a clear correlation between topoisomerase 2A (TOP2A) gene copy number or expression levels with the sensitivity to topoisomerase II inhibitors. Furthermore, CRISPR-Cas9 and shRNA screenings confirmed that loss-of-function of the TOP2A has the highest efficacy in reducing cellular proliferation. Finally, we observed significant TOP2A copy number gains and increased expression in independent cohorts of rectal cancer patients. These findings can be translated into clinical practice to evaluate TOP2A status for targeted and personalized therapies based on topoisomerase II inhibitors in rectal cancer patients.

MiR-125a-3p and MiR-320b Differentially Expressed in Patients with Chronic Myeloid Leukemia Treated with Allogeneic Hematopoietic Stem Cell Transplantation and Imatinib Mesylate

Chronic myeloid leukemia (CML), a hematopoietic neoplasm arising from the fusion of BCR (breakpoint cluster region) gene on chromosome 22 to the ABL (Abelson leukemia virus) gene on chromosome 9 (BCR-ABL1 oncogene), originates from a small population of leukemic stem cells with extensive capacity for self-renewal and an inflammatory microenvironment. Currently, CML treatment is based on tyrosine kinase inhibitors (TKIs). However, allogeneic hematopoietic stem cell transplantation (HSCT-allo) is currently the only effective treatment of CML. The difficulty of finding a compatible donor and high rates of morbidity and mortality limit transplantation treatment. Despite the safety and efficacy of TKIs, patients can develop resistance. Thus, microRNAs (miRNAs) play a prominent role as biomarkers and post-transcriptional regulators of gene expression. The aim of this study was to analyze the miRNA profile in CML patients who achieved cytogenetic remission after treatment with both HSCT-allo and TKI. Expression analyses of the 758 miRNAs were performed using reverse transcription quantitative polymerase chain reaction (RT-qPCR). Bioinformatics tools were used for data analysis. We detected miRNA profiles using their possible target genes and target pathways. MiR-125a-3p stood out among the downregulated miRNAs, showing an interaction network with 52 target genes. MiR-320b was the only upregulated miRNA, with an interaction network of 26 genes. The results are expected to aid future studies of miRNAs, residual leukemic cells, and prognosis in CML.

Preventive training does not interfere with mRNA-encoding myosin and collagen expression during pulmonary arterial hypertension

To gain insight on the impact of preventive exercise during pulmonary arterial hypertension (PAH), we evaluated the gene expression of myosins and gene-encoding proteins associated with the extracellular matrix remodeling of right hypertrophied ventricles. We used 32 male Wistar rats, separated in four groups: Sedentary Control (S, n = 8); Control with Training (T, n = 8); Sedentary with Pulmonary Arterial Hypertension (SPAH, n = 8); and Pulmonary Arterial Hypertension with Training (TPAH, n = 8). All rats underwent a two-week adaptation period; T and TPAH group rats then proceeded to an eight-week training period on a treadmill. At the beginning of the 11th week, S and T groups received an intraperitoneal injection of saline, and SPAH and TPAH groups received an injection of monocrotaline (60 mg/kg). Rats in the T and TPAH groups then continued with the training protocol until the 13th week. We assessed exercise capacity, echocardiography analysis, Fulton's index, cross-sectional areas of cardiomyocytes, collagen content and types, and fractal dimension (FD). Transcript abundance of myosins and extracellular matrix genes were estimated through reverse transcription-quantitative PCR (RT-qPCR). When compared to the SPAH group, the TPAH group showed increases in functional capacity and pulmonary artery acceleration time/pulmonary ejection time ratio and decreases in Fulton's index and cross-sectional areas of myocyte cells. However, preventive exercise did not induce alterations in col1a1 and myh7 gene expression. Our findings demonstrate that preventive exercise improved functional capacity, reduced cardiac hypertrophy, and attenuated PH development without interfering in mRNA-encoding myosin and collagen expression during PAH.

An insight on the impact of teleost whole genome duplication on the regulation of the molecular networks controlling skeletal muscle growth

Fish muscle growth is a complex process regulated by multiple pathways, resulting on the net accumulation of proteins and the activation of myogenic progenitor cells. Around 350–320 million years ago, teleost fish went through a specific whole genome duplication (WGD) that expanded the existent gene repertoire. Duplicated genes can be retained by different molecular mechanisms such as subfunctionalization, neofunctionalization or redundancy, each one with different functional implications. While the great majority of ohnolog genes have been identified in the teleost genomes, the effect of gene duplication in the fish physiology is still not well characterized. In the present study we studied the effect of WGD on the transcription of the duplicated components controlling muscle growth. We compared the expression of lineage-specific ohnologs related to myogenesis and protein balance in the fast-skeletal muscle of pacus (Piaractus mesopotamicus—Ostariophysi) and Nile tilapias (Oreochromis niloticus—Acanthopterygii) fasted for 4 days and refed for 3 days. We studied the expression of 20 ohnologs and found that in the great majority of cases, duplicated genes had similar expression profiles in response to fasting and refeeding, indicating that their functions during growth have been conserved during the period after the WGD. Our results suggest that redundancy might play a more important role in the retention of ohnologs of regulatory pathways than initially thought. Also, comparison to non-duplicated orthologs showed that it might not be uncommon for the duplicated genes to gain or loss new regulatory elements simultaneously. Overall, several of duplicated ohnologs have similar transcription profiles in response to pro-growth signals suggesting that evolution tends to conserve ohnolog regulation during muscle development and that in the majority of ohnologs related to muscle growth their functions might be very similar.

TLR4 deficiency upregulates TLR9 expression and enhances irinotecan-related intestinal mucositis and late-onset diarrhoea

BACKGROUND AND PURPOSE

Severe diarrhoea, a common gastrointestinal manifestation of anticancer treatment with irinotecan, might involve single nucleotide polymorphisms (SNPs) of toll-like receptors (TLRs), described as critical bacterial sensors in the gut. Here, colorectal cancer patients carrying missense TLR4 A896G (rs4986790) or C1,196T (rs4986791) SNPs and Tlr4 knockout (Tlr4-/-) mice were given irinotecan to investigate the severity of the induced diarrhoea.

EXPERIMENTAL APPROACH

Forty-six patients treated with irinotecan-based regimens had diarrhoea severity analysed according to TLR4 genotypes. In the experimental setting, wild-type (WT) or Tlr4-/- mice were given irinotecan (45 or 75 mg·kg^-1 , i.p.) or saline (3 ml·kg^-1 ). Diarrhoea severity was evaluated by measuring intestinal injury and inflammatory markers expression after animals were killed.

KEY RESULTS

All patients with TLR4 SNPs chemotherapy-treated presented diarrhoea, whereas gastrointestinal toxicity was observed in 50% of the wild homozygous individuals. Mice injected with irinotecan presented systemic bacterial translocation and increased TLR4 immunostaining in the intestine. In line with the clinical findings, Tlr4 gene deficiency enhanced irinotecan-related diarrhoea and TLR9 expression in mice. An increased myeloperoxidase activity and Il-18 expression along with IL-10 decreased production in Tlr4-/- mice also indicated an intensified intestinal damage and inflammatory response.

CONCLUSION AND IMPLICATIONS

TLR4 deficiency upregulates TLR9 expression and enhances intestinal damage and the severity of late-onset diarrhoea during irinotecan-based treatment. Identifying patients genetically predisposed to chemotherapy-associated diarrhoea is a strategy toward precision medicine.

Maternal protein restriction changes structural and metabolic gene expression in the skeletal muscle of aging offspring rats

Maternal protein restriction affects postnatal skeletal muscle physiology with impacts that last through senility. To investigate the morphological and molecular characteristics of skeletal muscle in aging rats subjected to maternal protein restriction, we used aged male rats (540 days old) born of dams fed a protein restricted diet (6% protein) during pregnancy and lactation. Using morphological, immunohistochemical and molecular analyses, we evaluated the soleus (SOL) and extensor digitorum longus (EDL) muscles, muscle fiber cross-sectional area (CSA) (n=8), muscle fiber frequency (n=5) and the gene expression (n=8) of the oxidative markers (succinate dehydrogenase-Sdha and citrate synthase-CS) and the glycolytic marker (lactate dehydrogenase-Ldha). Global transcriptome analysis (n=3) was also performed to identify differentially regulated genes, followed by gene expression validation (n=8). The oxidative SOL muscle displayed a decrease in muscle fiber CSA (*p<0.05) and in the expression of oxidative metabolism marker Sdha (***p<0.001), upregulation of the anabolic Igf-1 (**p<0.01), structural Chad (**p<0.01), and Fmod (*p<0.05) genes, and downregulation of the Hspb7 (**p<0.01) gene. The glycolytic EDL muscle exhibited decreased IIA (*p<0.05) and increased IIB (*p<0.05) fiber frequency, and no changes in muscle fiber CSA or in the expression of oxidative metabolism genes. In contrast, the gene expression of Chad (**p<0.01) was upregulated and the Myog (**p<0.01) gene was downregulated. Collectively, our morphological, immunohistochemical and molecular analyses showed that maternal protein restriction induced changes in the expression of metabolic, anabolic, myogenic, and structural genes, mainly in the oxidative SOL muscle, in aged offspring rats.

Long-term persistence of supernumerary B chromosomes in multiple species of Astyanax fish

BACKGROUND

Eukaryote genomes frequently harbor supernumerary B chromosomes in addition to the "standard" A chromosome set. B chromosomes are thought to arise as byproducts of genome rearrangements and have mostly been considered intraspecific oddities. However, their evolutionary transcendence beyond species level has remained untested.

RESULTS

Here we reveal that the large metacentric B chromosomes reported in several fish species of the genus Astyanax arose in a common ancestor at least 4 million years ago. We generated transcriptomes of A. scabripinnis and A. paranae 0B and 1B individuals and used these assemblies as a reference for mapping all gDNA and RNA libraries to quantify coverage differences between B-lacking and B-carrying genomes. We show that the B chromosomes of A. scabripinnis and A. paranae share 19 protein-coding genes, of which 14 and 11 were also present in the B chromosomes of A. bockmanni and A. fasciatus, respectively. Our search for B-specific single-nucleotide polymorphisms (SNPs) identified the presence of B-derived transcripts in B-carrying ovaries, 80% of which belonged to nobox, a gene involved in oogenesis regulation. Importantly, the B chromosome nobox paralog is expressed > 30× more than the A chromosome paralog. This indicates that the normal regulation of this gene is altered in B-carrying females, which could potentially facilitate B inheritance at higher rates than Mendelian law prediction.

CONCLUSIONS

Taken together, our results demonstrate the long-term survival of B chromosomes despite their lack of regular pairing and segregation during meiosis and that they can endure episodes of population divergence leading to species formation.

Ascorbic Acid Supplementation Improves Skeletal Muscle Growth in Pacu (Piaractus mesopotamicus) Juveniles: In Vivo and In Vitro Studies

In fish, fasting leads to loss of muscle mass. This condition triggers oxidative stress, and therefore, antioxidants can be an alternative to muscle recovery. We investigated the effects of antioxidant ascorbic acid (AA) on the morphology, antioxidant enzyme activity, and gene expression in the skeletal muscle of pacu (Piaractus mesopotamicus) following fasting, using in vitro and in vivo strategies. Isolated muscle cells of the pacu were subjected to 72 h of nutrient restriction, followed by 24 h of incubation with nutrients or nutrients and AA (200 µM). Fish were fasted for 15 days, followed by 6 h and 15 and 30 days of refeeding with 100, 200, and 400 mg/kg of AA supplementation. AA addition increased cell diameter and the expression of anabolic and cell proliferation genes in vitro. In vivo, 400 mg/kg of AA increased anabolic and proliferative genes expression at 6 h of refeeding, the fiber diameter and the expression of genes related to cell proliferation at 15 days, and the expression of catabolic and oxidative metabolism genes at 30 days. Catalase activity remained low in the higher supplementation group. In conclusion, AA directly affected the isolated muscle cells, and the higher AA supplementation positively influenced muscle growth after fasting.

Prediction of SARS-CoV Interaction with Host Proteins during Lung Aging Reveals a Potential Role for TRIB3 in COVID-19

COVID-19 is prevalent in the elderly. Old individuals are more likely to develop pneumonia and respiratory failure due to alveolar damage, suggesting that lung senescence may increase the susceptibility to SARS-CoV-2 infection and replication. Considering that human coronavirus (HCoVs; SARS-CoV-2 and SARS-CoV) require host cellular factors for infection and replication, we analyzed Genotype-Tissue Expression (GTEx) data to test whether lung aging is associated with transcriptional changes in human protein-coding genes that potentially interact with these viruses. We found decreased expression of the gene tribbles homolog 3 (TRIB3) during aging in male individuals, and its protein was predicted to interact with HCoVs nucleocapsid protein and RNA-dependent RNA polymerase. Using publicly available lung single-cell data, we found TRIB3 expressed mainly in alveolar epithelial cells that express SARS-CoV-2 receptor ACE2. Functional enrichment analysis of age-related genes, in common with SARS-CoV-induced perturbations, revealed genes associated with the mitotic cell cycle and surfactant metabolism. Given that TRIB3 was previously reported to decrease virus infection and replication, the decreased expression of TRIB3 in aged lungs may help explain why older male patients are related to more severe cases of the COVID-19. Thus, drugs that stimulate TRIB3 expression should be evaluated as a potential therapy for the disease.

Transcriptome of Two Canine Prostate Cancer Cells Treated With Toceranib Phosphate Reveals Distinct Antitumor Profiles Associated With the PDGFR Pathway

Canine prostate cancer (PC) presents a poor antitumor response, usually late diagnosis and prognosis. Toceranib phosphate (TP) is a nonspecific inhibitor of receptor tyrosine kinases (RTKs), including vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR), and c-KIT. This study aimed to evaluate VEGFR2, PDGFR-β, and c-KIT protein expression in two established canine PC cell lines (PC1 and PC2) and the transcriptome profile of the cells after treatment with TP. Immunofluorescence (IF) analysis revealed VEGFR2 and PDGFR-β protein expression and the absence of c-KIT protein expression in both cell lines. After TP treatment, only the viability of PC1 cells decreased in a dose-dependent manner. Transcriptome and enrichment analyses of treated PC1 cells revealed 181 upregulated genes, which were related to decreased angiogenesis and cell proliferation. In addition, we found upregulated PDGFR-A, PDGFR-β, and PDGF-D expression in PC1 cells, and the upregulation of PDGFR-β was also observed in treated PC1 cells by qPCR. PC2 cells had fewer protein-protein interactions (PPIs), with 18 upregulated and 22 downregulated genes; the upregulated genes were involved in the regulation of parallel pathways and mechanisms related to proliferation, which could be associated with the resistance observed after treatment. The canine PC1 cell line but not the PC2 cell line showed decreased viability after treatment with TP, although both cell lines expressed PDGFR and VEGFR receptors. Further studies could explain the mechanism of resistance in PC2 cells and provide a basis for personalized treatment for dogs with PC.

A meta-analysis of microRNA networks regulated by melatonin in cancer: Portrait of potential candidates for breast cancer treatment

Melatonin is a ubiquitous molecule with a broad spectrum of functions including widespread anti-cancer activities. Identifying how melatonin intervenes in complex molecular signaling at the gene level is essential to guide proper therapies. Using meta-analysis approach, herein we examined the role of melatonin in regulating the expression of 46 microRNAs (miRNAs) and their target genes in breast, oral, gastric, colorectal, and prostate cancers, and glioblastoma. The deregulated miRNA-associated target genes revealed their involvement in the regulation of cellular proliferation, differentiation, apoptosis, senescence, and autophagy. Melatonin changes the expression of miRNA-associated genes in breast, gastric, and oral cancers. These genes are associated with cellular senescence, the hedgehog signaling pathway, cell proliferation, p53 signaling, and the hippo signaling pathway. Conversely, colorectal and prostate cancers as well as glioblastoma and oral carcinoma present a clear pattern of less pronounced changes in the expression of miRNA-associated genes. Most notably, colorectal cancer displayed a unique molecular change in response to melatonin. Considering breast cancer network complexity, we compared the genes found during the meta-analysis with RNA-Seq data from breast cancer-bearing mice treated with melatonin. Mechanistically, melatonin upregulated genes associated with immune responses and apoptotic processes, whereas it downregulated genes involved in cellular aggressiveness/metastasis (eg, mitosis, telomerase activity, and angiogenesis). We further characterized the expression profile of our gene subsets with human breast cancer and found eight upregulated genes and 16 downregulated genes that were appositively correlated with melatonin. Our results pose a multi-dimension network of tumor-associated genes regulated by miRNAs potentially targeted by melatonin.

Identification of potential molecular pathways involved in prostate carcinogenesis in offspring exposed to maternal malnutrition

The developmental origins of health and disease concept links adult diseases with early-life exposure to inappropriate environmental conditions. Intrauterine and postnatal malnutrition may lead to an increased incidence of type 2 diabetes, obesity, and cardiovascular diseases. Maternal malnutrition (MM) has also been associated with prostate carcinogenesis. However, the molecular mechanisms associated with this condition remain poorly understood. Using a proteomic analysis, we demonstrated that MM changed the levels of proteins associated with growth factors, estrogen signaling, detoxification, and energy metabolism in the prostate of both young and old rats. These animals also showed increased levels of molecular markers of endoplasmic reticulum function and histones. We further performed an in silico analysis that identified commonly deregulated proteins in the ventral prostate of old rats submitted to MM with a mouse model and patients with prostate cancer. In conclusion, our results demonstrated that estrogenic signaling pathways, endoplasmic reticulum functions, energy metabolism, and molecular sensors of protein folding and Ca2+ homeostasis, besides histone, and RAS-GTPase family appear to be involved in this process. Knowledge of these factors may raise discussions regarding the role of maternal dietary intervention as a public policy for the lifelong prevention of chronic diseases.

Comparison of microRNA Expression Profile in Chronic Myeloid Leukemia Patients Newly Diagnosed and Treated by Allogeneic Hematopoietic Stem Cell Transplantation

Chronic myeloid leukemia (CML) results from a translocation between chromosomes 9 and 22, which generates the Philadelphia chromosome. This forms BCR/ABL1, an active tyrosine kinase protein that promotes cell growth and replication. Despite great progress in CML treatment in the form of tyrosine kinase inhibitors, allogeneic-hematopoietic stem cell transplantation (allo-HSCT) is currently used as an important treatment alternative for patients resistant to these inhibitors. Studies have shown that unregulated expression of microRNAs, which act as oncogenes or tumor suppressors, is associated with human cancers. This contributes to tumor formation and development by stimulating proliferation, angiogenesis, and invasion. Research has demonstrated the potential of microRNAs as biomarkers for cancer diagnosis, prognosis, and therapeutic targets. In the present study, we compared the circulating microRNA expression profiles of 14 newly diagnosed patients with chronic phase-CML and 14 Philadelphia chromosome-negative patients after allo-HSCT. For each patient, we tested 758 microRNAs by reverse transcription quantitative polymerase chain reaction (RT-qPCR) analysis. The global expression profile of microRNAs revealed 16 upregulated and 30 downregulated microRNAs. Target genes were analyzed, and key pathways were extracted and compared. Bioinformatics tools were used to analyze data. Among the downregulated miRNA target genes, some genes related to cell proliferation pathways were identified. These results reveal the comprehensive microRNA profile of CML patients and the main pathways related to the target genes of these miRNAs in cytogenetic remission after allo-HSCT. These results provide new resources for exploring stem cell transplantation-based CML treatment strategies.

Partial luteolysis during early diestrus in cattle downregulates VEGFA expression and reduces large luteal cell and corpus luteum sizes and plasma progesterone concentration

Our objectives were to investigate potential changes in the size of steroidogenic large luteal cells (LLC) during partial luteolysis induced by a sub-dose of cloprostenol in early diestrus and to determine transcriptional variations in genes involved in corpus luteum (CL) functions. Cows were subjected to an Ovsynch protocol, with the time of the second GnRH treatment defined as Day 0 (D0). On D6, cows were randomly allocated into three treatments: Control (2 mL saline, im; n = 10), 2XPGF (two doses of 500 μg of cloprostenol, im, 2 h apart; n = 8) or 1/6PGF (single dose of 83.3 μg of cloprostenol, im; n = 10). Before treatments and every 8 h during the 48-h experimental period, blood samples were collected and CL volumes measured. Furthermore, two CL biopsies were obtained at 24 and 40 h post-treatment. The 1/6PGF treatment caused partial luteolysis, characterized by sudden decreases in plasma progesterone (P₄) concentrations, luteal volume and LLC size, followed by increases (to pretreatment values) in P₄ and luteal volume at 24 and 40 h post-treatment, respectively. However, at the end of the study, P4, luteal volume and LLC size were all significantly smaller than in Control cows. Temporally associated with these phenotypes, there was a lower mRNA abundance of VEGFA at 24 and 40 h, and ABCA1 at 24 h (P < 0.05). In conclusion, a sudden reduction in CL size during partial luteolysis induced by a sub-dose of PGF_2α analog on day 6 of the estrous cycle was attributed to a reduction in LLC size, although these changes did not account for the entire phenomenon. In addition to its involvement in reducing CL size, decreased VEGFA mRNA abundance impaired CL development, resulting in a smaller luteal gland and lower plasma P₄ concentrations compared to Control cows.

Effect of the Photo-initiator System Contained in Universal Adhesives on Radicular Dentin Bonding

CLINICAL RELEVANCE

The photo-initiator system based on an advanced polymerization system may be an alternative that can be used to overcome the disadvantages of radicular dentin, especially for the apical third.

SUMMARY

Objectives: The purpose of this study was to evaluate the effects of universal adhesives with different photo-initiator systems applied in etch-and-rinse (ER) and self-etch (SE) modes on dentin interaction (push-out bond strength [PBS], nanoleakage [NL], and degree of conversion [DC] within the hybrid layer) in the different root thirds after fiber post cementation.Methods and Materials: Roots of endodontically prepared human premolars were randomly divided into six groups according to one of three adhesive systems (Scotchbond Universal [SBU], Ambar Universal [AMB], and Ambar Universal APS [AMB-APS]) and two adhesive strategies (ER and SE) for each system. Posts were cemented, and PBS was tested at 0.5 mm/min. The NL was evaluated by scanning electron microscopy. DC was measured using micro-Raman spectroscopy. The data were analyzed by three-way analysis of variance and Tukey tests (α=0.05).Results: AMB-APS showed similar performance in all root thirds (p>0.05) and higher values of DC, especially in the apical third (p<0.0001). AMB and SBU showed the lowest values in the apical third (p<0.0001).Conclusions: The APS photo-initiator system contained in universal adhesives is a feasible alternative for improving radicular bonding procedure.

Elevated Glucose Levels Favor SARS-CoV-2 Infection and Monocyte Response through a HIF-1α/Glycolysis-Dependent Axis

COVID-19 can result in severe lung injury. It remained to be determined why diabetic individuals with uncontrolled glucose levels are more prone to develop the severe form of COVID-19. The molecular mechanism underlying SARS-CoV-2 infection and what determines the onset of the cytokine storm found in severe COVID-19 patients are unknown. Monocytes and macrophages are the most enriched immune cell types in the lungs of COVID-19 patients and appear to have a central role in the pathogenicity of the disease. These cells adapt their metabolism upon infection and become highly glycolytic, which facilitates SARS-CoV-2 replication. The infection triggers mitochondrial ROS production, which induces stabilization of hypoxia-inducible factor-1α (HIF-1α) and consequently promotes glycolysis. HIF-1α-induced changes in monocyte metabolism by SARS-CoV-2 infection directly inhibit T cell response and reduce epithelial cell survival. Targeting HIF-1ɑ may have great therapeutic potential for the development of novel drugs to treat COVID-19.

The expression landscape of cachexia-inducing factors in human cancers

BACKGROUND

Cachexia is a multifactorial syndrome highly associated with specific tumour types, but the causes of variation in cachexia prevalence and severity are unknown. While circulating plasma mediators (soluble cachectic factors) derived from tumours have been implicated with the pathogenesis of the syndrome, these associations were generally based on plasma concentration rather than tissue-specific gene expression levels. Here, we hypothesized that tumour gene expression profiling of cachexia-inducing factors (CIFs) in human cancers with different prevalence of cachexia could reveal potential cancer-specific cachexia mediators and biomarkers of clinical outcome.

METHODS

First, we combined uniformly processed RNA sequencing data from The Cancer Genome Atlas and Genotype-Tissue Expression databases to characterize the expression profile of secretome genes in 12 cancer types (4651 samples) compared with their matched normal tissues (2737 samples). We systematically investigated the transcriptomic data to assess the tumour expression profile of 25 known CIFs and their predictive values for patient survival. We used the Xena Functional Genomics tool to analyse the gene expression of CIFs according to neoplastic cellularity in pancreatic adenocarcinoma, which is known to present the highest prevalence of cachexia.

RESULTS

A comprehensive characterization of the expression profiling of secreted genes in different human cancers revealed pathways and mediators with a potential role in cachexia within the tumour microenvironment. Cytokine-related and chemokine-related pathways were enriched in tumour types frequently associated with the syndrome. CIFs presented a tumour-specific expression profile, in which the number of upregulated genes was correlated with the cachexia prevalence (r2 : 0.80; P value: 0.002) and weight loss (r2 : 0.81; P value: 0.002). The distinct gene expression profile, according to tumour type, was significantly associated with prognosis (P value ≤ 1.96 E-06). In pancreatic adenocarcinoma, the upregulated CIF genes were associated with tumours presenting low neoplastic cellularity and high leucocyte fraction and not with tumour grade.

CONCLUSIONS

Our results present a biological dimension of tumour-secreted elements that are potentially useful to explain why specific cancer types are more likely to develop cachexia. The tumour-specific profile of CIFs may help the future development of better targeted therapies to treat cancer types highly associated with the syndrome.

MicroRNA-mRNA Co-sequencing Identifies Transcriptional and Post-transcriptional Regulatory Networks Underlying Muscle Wasting in Cancer Cachexia

Cancer cachexia is a metabolic syndrome with alterations in gene regulatory networks that consequently lead to skeletal muscle wasting. Integrating microRNAs-mRNAs omics profiles offers an opportunity to understand transcriptional and post-transcriptional regulatory networks underlying muscle wasting. Here, we used RNA sequencing to simultaneously integrate and explore microRNAs and mRNAs expression profiles in the tibialis anterior (TA) muscles of the Lewis Lung Carcinoma (LLC) model of cancer cachexia. We found 1,008 mRNAs and 18 microRNAs differentially expressed in cachectic mice compared with controls. Although our transcriptomic analysis demonstrated a high heterogeneity in mRNA profiles of cachectic mice, we identified a reduced number of differentially expressed genes that were uniformly regulated within cachectic muscles. This set of uniformly regulated genes is associated with the extracellular matrix (ECM), proteolysis, and inflammatory response. We also used transcriptomic data to perform enrichment analysis of transcriptional factor binding sites in promoter sequences, which revealed activation of the atrophy-related transcription factors NF-κB, Stat3, AP-1, and FoxO. Furthermore, the integration of mRNA and microRNA expression profiles identified post-transcriptional regulation by microRNAs of genes involved in ECM organization, cell migration, transcription factors binding, ion transport, and the FoxO signaling pathway. Our integrative analysis of microRNA-mRNA co-profiles comprehensively characterized regulatory relationships of molecular pathways and revealed microRNAs targeting ECM-associated genes in cancer cachexia.

Short communication: Heat stress does not affect induced luteolysis in Holstein cows

Heat stress (HS) has deleterious effects on bovine reproduction, including prolongation of the luteal phase in Holstein cows, perhaps due to compromised luteolysis. The objective was to characterize effects of HS on luteolytic responses of nonlactating Holstein cows given 25 or 12.5 mg of PGF_2α on d 7 of the estrous cycle. Cows were randomly distributed into 2 environments: thermoneutral (n = 12; 25°C) or HS (n = 12; 36°C). In each environment, cows were treated with 2 mL of saline, 25 or 12.5 mg of PGF_2α (n = 4 cows per group). The HS environment induced a significant increase in rectal temperature and respiratory rate compared with the thermoneutral environment. Heat stress did not have significant effects on luteolytic responses or circulating progesterone concentrations. Rapid and complete luteolysis occurred in all cows given 25 mg of PGF_2α and in 4 of 8 cows given 12.5 mg; the other 4 cows given 12.5 mg had partial luteolysis, with circulating progesterone concentrations initially suppressed, but subsequently rebounding. Therefore, we conclude that HS does not change corpus luteum sensitivity to PGF_2α.

An Integrated Meta-Analysis of Secretome and Proteome Identify Potential Biomarkers of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is extremely aggressive, has an unfavorable prognosis, and there are no biomarkers for early detection of the disease or identification of individuals at high risk for morbidity or mortality. The cellular and molecular complexity of PDAC leads to inconsistences in clinical validations of many proteins that have been evaluated as prognostic biomarkers of the disease. The tumor secretome, a potential source of biomarkers in PDAC, plays a crucial role in cell proliferation and metastasis, as well as in resistance to treatments, which together contribute to a worse clinical outcome. The massive amount of proteomic data from pancreatic cancer that has been generated from previous studies can be integrated and explored to uncover secreted proteins relevant to the diagnosis and prognosis of the disease. The present study aimed to perform an integrated meta-analysis of PDAC proteome and secretome public data to identify potential biomarkers of the disease. Our meta-analysis combined mass spectrometry data obtained from two systematic reviews of the pancreatic cancer literature, which independently selected 20 studies of the secretome and 35 of the proteome. Next, we predicted the secreted proteins using seven in silico tools or databases, which identified 39 secreted proteins shared between the secretome and proteome data. Notably, the expression of 31 genes of these secretome-related proteins was upregulated in PDAC samples from The Cancer Genome Atlas (TCGA) when compared to control samples from TCGA and The Genotype-Tissue Expression (GTEx). The prognostic value of these 39 secreted proteins in predicting survival outcome was confirmed using gene expression data from four PDAC datasets (validation set). The gene expression of these secreted proteins was able to distinguish high- and low-survival patients in nine additional tumor types from TCGA, demonstrating that deregulation of these secreted proteins may also contribute to the prognosis in multiple cancers types. Finally, we compared the prognostic value of the identified secreted proteins in PDAC biomarkers studies from the literature. This analysis revealed that our gene signature performed equally well or better than the signatures from these previous studies. In conclusion, our integrated meta-analysis of PDAC proteome and secretome identified 39 secreted proteins as potential biomarkers, and the tumor gene expression profile of these proteins in patients with PDAC is associated with worse overall survival.

Increased DSG2 plasmatic levels identified by transcriptomic-based secretome analysis is a potential prognostic biomarker in laryngeal carcinoma

OBJECTIVES

The tumor secretome deconvolution is a promising strategy to identify diagnostic and prognostic biomarkers. Here, transcriptomic-based secretome analysis was performed aiming to discover laryngeal squamous cell carcinomas (LSCC) biomarkers from potentially secreted proteins (PSPs).

MATERIAL AND METHODS

The tumor expression profile (35 LSCC biopsies compared with surrounding normal tissues - SN) revealed 589 overexpressed genes. This gene list was used for secretome analysis based on laryngeal tumors and related secretome databases.

RESULTS

Forty-nine (Laryngeal tumor secretome database) and 50 (Human Protein Atlas and Cancer Secretome Database) PSPs presented an association with worse overall survival. Specifically, DSG2 overexpression was strongly correlated with poor survival and distant metastasis. DSG2 increased expression was confirmed in the LSCC dataset (LSCC = 111; SN = 12) from TCGA. A significant association between shorter survival and DSG2 overexpression was also detected. In an independent cohort of cases, we analyzed and confirmed high protein levels of DSG2 in plasma from LSCC patients.

CONCLUSION

A set of PSPs including the circulating DSG2, were associated with shorter overall survival in LSCC. DSG2 overexpression was also correlated with distant metastasis. The high plasmatic protein levels of DSG2 suggest its potential to be tested in liquid biopsies and applied as prognostic biomarker of LSCC.

Prolonged fasting followed by refeeding modifies proteome profile and parvalbumin expression in the fast-twitch muscle of pacu (Piaractus mesopotamicus)

Here, we analyzed the fast-twitch muscle of juvenile Piaractus mesopotamicus (pacu) submitted to prolonged fasting (30d) and refeeding (6h, 24h, 48h and 30d). We measured the relative rate of weight and length increase (RRI_length and RRI_weight), performed shotgun proteomic analysis and did Western blotting for PVALB after 30d of fasting and 30d of refeeding. We assessed the gene expression of igf-1, mafbx and pvalb after 30d of fasting and after 6h, 24h, 48h and 30d of refeeding. We performed a bioinformatic analysis to predict miRNAs that possibly control parvalbumin expression. After fasting, RRI_length, RRI_weight and igf-1 expression decreased, while the mafbx expression increased, which suggest that prolonged fasting caused muscle atrophy. After 6h and 24h of refeeding, mafbx was not changed and igf-1 was downregulated, while after 48h of refeeding mafbx was downregulated and igf-1 was not changed. After 30d of refeeding, RRI_length and RRI_weight were increased and igf-1 and mafbx expression were not changed. Proteomic analysis identified 99 proteins after 30d of fasting and 71 proteins after 30d of refeeding, of which 23 and 17, respectively, were differentially expressed. Most of these differentially expressed proteins were related to cytoskeleton, muscle contraction, and metabolism. Among these, parvalbumin (PVALB) was selected for further validation. The analysis showed that pvalb mRNA was downregulated after 6h and 24h of refeeding, but was not changed after 30d of fasting or 48h and 30d of refeeding. The Western blotting confirmed that PVALB protein was downregulated after 30d of fasting and 30d of refeeding. The downregulation of the protein and the unchanged expression of the mRNA after 30d of fasting and 30d of refeeding suggest a post-transcriptional regulation of PVALB. Our miRNA analysis predicted 444 unique miRNAs that may target pvalb. In conclusion, muscle atrophy and partial compensatory growth caused by prolonged fasting followed by refeeding affected the muscle proteome and PVALB expression.

Tumor Transcriptome Reveals High Expression of IL-8 in Non-Small Cell Lung Cancer Patients with Low Pectoralis Muscle Area and Reduced Survival

Cachexia is a syndrome characterized by an ongoing loss of skeletal muscle mass associated with poor patient prognosis in non-small cell lung cancer (NSCLC). However, prognostic cachexia biomarkers in NSCLC are unknown. Here, we analyzed computed tomography (CT) images and tumor transcriptome data to identify potentially secreted cachexia biomarkers (PSCB) in NSCLC patients with low-muscularity. We integrated radiomics features (pectoralis muscle, sternum, and tenth thoracic (T10) vertebra) from CT of 89 NSCLC patients, which allowed us to identify an index for screening muscularity. Next, a tumor transcriptomic-based secretome analysis from these patients (discovery set) was evaluated to identify potential cachexia biomarkers in patients with low-muscularity. The prognostic value of these biomarkers for predicting recurrence and survival outcome was confirmed using expression data from eight lung cancer datasets (validation set). Finally, C2C12 myoblasts differentiated into myotubes were used to evaluate the ability of the selected biomarker, interleukin (IL)-8, in inducing muscle cell atrophy. We identified 75 over-expressed transcripts in patients with low-muscularity, which included IL-6, CSF3, and IL-8. Also, we identified NCAM1, CNTN1, SCG2, CADM1, IL-8, NPTX1, and APOD as PSCB in the tumor secretome. These PSCB were capable of distinguishing worse and better prognosis (recurrence and survival) in NSCLC patients. IL-8 was confirmed as a predictor of worse prognosis in all validation sets. In vitro assays revealed that IL-8 promoted C2C12 myotube atrophy. Tumors from low-muscularity patients presented a set of upregulated genes encoding for secreted proteins, including pro-inflammatory cytokines that predict worse overall survival in NSCLC. Among these upregulated genes, IL-8 expression in NSCLC tissues was associated with worse prognosis, and the recombinant IL-8 was capable of triggering atrophy in C2C12 myotubes.

Locally advanced rectal cancer transcriptomic-based secretome analysis reveals novel biomarkers useful to identify patients according to neoadjuvant chemoradiotherapy response

Most patients with locally advanced rectal cancer (LARC) present incomplete pathological response (pIR) to neoadjuvant chemoradiotherapy (nCRT). Despite the efforts to predict treatment response using tumor-molecular features, as differentially expressed genes, no molecule has proved to be a strong biomarker. The tumor secretome analysis is a promising strategy for biomarkers identification, which can be assessed using transcriptomic data. We performed transcriptomic-based secretome analysis to select potentially secreted proteins using an in silico approach. The tumor expression profile of 28 LARC biopsies collected before nCRT was compared with normal rectal tissues (NT). The expression profile showed no significant differences between complete (pCR) and incomplete responders to nCRT. Genes with increased expression (pCR = 106 and pIR = 357) were used for secretome analysis based on public databases (Vesiclepedia, Human Cancer Secretome, and Plasma Proteome). Seventeen potentially secreted candidates (pCR = 1, pIR = 13 and 3 in both groups) were further investigated in two independent datasets (TCGA and GSE68204) confirming their over-expression in LARC and association with nCRT response (GSE68204). The expression of circulating amphiregulin and cMET proteins was confirmed in serum from 14 LARC patients. Future studies in liquid biopsies could confirm the utility of these proteins for personalized treatment in LARC patients.

The combination of resveratrol and exercise enhances muscle growth characteristics in pacu (Piaractus mesopotamicus)

Pacu is a tropical fish with important value to aquaculture. During cellular metabolism, reactive oxygen species (ROS) are produced, which can influence muscle growth. Resveratrol is an effective antioxidant that scavenges ROS and can modulate physical performance preventing oxidative stress. We investigated the effects of resveratrol and exercise on pacu muscle growth characteristics. Four groups were used: fish fed with control diet /without exercise (C); fish fed with control diet/subjected to exercise (CE); fish fed resveratrol-supplemented diet/without exercise (R); and fish fed resveratrol-supplemented diet/subjected to exercise (RE). At 30 days, the RE group presented a significant increase in body weight, fewer muscle fibers in the 20-40 μm and more fibers in the >60 μm diameter class compared to the C group. At day 7, catalase activity decreased in CE and RE groups. Superoxide dismutase activity decreased only in the CE group. Myod and mtor gene expression was higher in R and RE and igf-1 was up-regulated in the RE group. Murf1a level decreased in CE, R, and RE, while sdha expression was higher in the RE group. We suggest that resveratrol in combination with exercise was beneficial for muscle growth and metabolism, increasing the expression levels of genes related to muscle anabolism and oxidative metabolism, besides the decrease of catabolic gene expression. Notably, all of these changes occurred together with muscle hypertrophy and increased body weight. Our results show a positive application for resveratrol in association with exercise as a strategy to improve the growth performance of juvenile pacus.

The Pathway to Cancer Cachexia: MicroRNA-Regulated Networks in Muscle Wasting Based on Integrative Meta-Analysis

Cancer cachexia is a multifactorial syndrome that leads to significant weight loss. Cachexia affects 50%-80% of cancer patients, depending on the tumor type, and is associated with 20%-40% of cancer patient deaths. Besides the efforts to identify molecular mechanisms of skeletal muscle atrophy-a key feature in cancer cachexia-no effective therapy for the syndrome is currently available. MicroRNAs are regulators of gene expression, with therapeutic potential in several muscle wasting disorders. We performed a meta-analysis of previously published gene expression data to reveal new potential microRNA-mRNA networks associated with muscle atrophy in cancer cachexia. We retrieved 52 differentially expressed genes in nine studies of muscle tissue from patients and rodent models of cancer cachexia. Next, we predicted microRNAs targeting these differentially expressed genes. We also include global microRNA expression data surveyed in atrophying skeletal muscles from previous studies as background information. We identified deregulated genes involved in the regulation of apoptosis, muscle hypertrophy, catabolism, and acute phase response. We further predicted new microRNA-mRNA interactions, such as miR-27a/Foxo1, miR-27a/Mef2c, miR-27b/Cxcl12, miR-27b/Mef2c, miR-140/Cxcl12, miR-199a/Cav1, and miR-199a/Junb, which may contribute to muscle wasting in cancer cachexia. Finally, we found drugs targeting MSTN, CXCL12, and CAMK2B, which may be considered for the development of novel therapeutic strategies for cancer cachexia. Our study has broadened the knowledge of microRNA-regulated networks that are likely associated with muscle atrophy in cancer cachexia, pointing to their involvement as potential targets for novel therapeutic strategies.

Osteoglycin post-transcriptional regulation by miR-155 induces cellular architecture changes in H9c2 cardiomyoblasts

Several studies have demonstrated dysregulated cardiac microRNAs (miRNAs) following cardiac stress and development of cardiac hypertrophy and failure. miRNAs are also differentially expressed in the inflammation that occurs in heart failure and, among these inflammatory-related miRNAs, the miR-155 has been implicated in the regulation of cardiac hypertrophy. Despite these data showing the role of miRNA-155 in cardiomyocyte hypertrophy under a hypertrophic stimulus, it is also important to understand the endogenous regulation of this miRNA without a hypertrophic stimulus to fully appreciate its function in this cell type. The first aim of the present study was to determine whether, without a hypertrophic stimulus, miR-155 overexpression induces H9c2 cardiac cells hypertrophy in vitro. The second objective was to determine whether osteoglycin (Ogn), a key regulator of heart mass in rats, mice, and humans, is post-transcriptionally regulated by miR-155 with a potential role in inducing H9c2 cells hypertrophy. Here, we show that, without a hypertrophic stimulus, miR-155 significantly repressed Ogn protein levels, but induce neither alteration in morphological phenotype nor in the expression of the molecular markers that fully characterize pathological hypertrophy of H9c2 cells. However, most importantly, Ogn silencing in H9c2 cells mimicked the effects of miR-155 overexpression in inducing cellular architecture changes that were characterized by a transition of the cell shape from fusiform to rounded. This is a new role of the post-transcriptional regulation of Ogn by miR-155 in the maintenance of the cardiac cell morphology in physiological and pathological conditions.

Can the antral follicular count modulate the gene expression of bovine oviducts in Aberdeen Angus and Nelore heifers?

The number of visible ovarian antral follicles (antral follicle count—AFC) is repeatable in bovine individuals, but highly variable between animals, and with differences between Bos taurus and Bos indicus breeds. Several studies have tried to determine the correlation between AFC and increased fertility in cattle. While the impacts of AFC on embryo production, hormonal levels, and pregnancy rates have been described, the molecular effects of AFC on bovine oviducts have not yet been investigated. Here, the aim was to investigate the impact of breeds, such as Aberdeen Angus and Nelore heifer with high or low AFC, on abundance of transcripts and protein related to oviductal transport, sperm reservoir formation, monospermy control, and gamete interaction in the oviducts. In summary, the ovulation side was the major factor that affected transcript abundance on bovine oviducts. However, a discreet effect among AFC and cattle breeds was also observed. Based on this, we concluded and reinforced here that differential microenvironments between ipsilateral and contralateral oviducts have a major effect on modulating the transcripts related to oviductal transport, sperm reservoir formation, monospermy control, and gamete interaction. However, we cannot exclude that there is minimal effect of AFC or breed on regulation of some genes (such as AGTR1, ACE1, FUCA1, and VEGFA) in bovine oviducts.

Fractal dimension analysis reveals skeletal muscle disorganization in mdx mice

Duchenne Muscular Dystrophy (DMD) is characterized by muscle extracellular matrix disorganization due to the increased collagen deposition leading to fibrosis that significantly exacerbates disease progression. Fractal dimension analysis is a method that quantifies tissue/cellular disorganization and characterizes complex structures. The first objective of the present study was use fractal analysis to evaluate extracellular matrix disorganization in mdx mice soleus muscle. Next, we mimic a hyper-proliferation of fibrogenic cells by co-culturing NIH3T3 fibroblasts and C2C12 myoblasts to test whether fibroblasts induce disorganization in myoblast arrangement. Here, we show mdx presented high skeletal muscle disorganization as revealed by fractal analysis. Similarly, this method revealed that myoblasts co-cultured with fibroblast also presented cellular arrangement disorganization. We also reanalyzed skeletal muscle microarrays transcriptomic data from mdx and DMD patients that revealed transcripts related to extracellular matrix organization. This analysis also identified Osteoglycin, which was validated as a potential regulator of ECM organization in mdx dystrophic muscles. Our results demonstrate that fractal dimension is useful tool for the analysis of skeletal muscle disorganization in DMD and also reveal a fibroblast-myoblast cross-talk that contributes to "in vitro" myoblast disarrangement.

Osteoglycin inhibition by microRNA miR-155 impairs myogenesis

Skeletal myogenesis is a regulated process in which mononucleated cells, the myoblasts, undergo proliferation and differentiation. Upon differentiation, the cells align with each other, and subsequently fuse to form terminally differentiated multinucleated myotubes. Previous reports have identified the protein osteoglycin (Ogn) as an important component of the skeletal muscle secretome, which is expressed differentially during muscle development. However, the posttranscriptional regulation of Ogn by microRNAs during myogenesis is unknown. Bioinformatic analysis showed that miR-155 potentially targeted the Ogn transcript at the 3´-untranslated region (3´ UTR). In this study, we tested the hypothesis that miR-155 inhibits the expression of the Ogn to regulate skeletal myogenesis. C2C12 myoblast cells were cultured and miR-155 overexpression or Ogn knockdown was induced by transfection with miR-155 mimic, siRNA-Ogn, and negative controls with lipofectamine for 15 hours. Near confluence (80–90%), myoblasts were induced to differentiate myotubes in a differentiation medium. Luciferase assay was used to confirm the interaction between miR-155 and Ogn 3’UTR. RT-qPCR and Western blot analyses were used to confirm that the differential expression of miR-155 correlates with the differential expression of myogenic molecular markers (Myh2, MyoD, and MyoG) and inhibits Ogn protein and gene expression in myoblasts and myotubes. Myoblast migration and proliferation were assessed using Wound Healing and MTT assays. Our results show that miR-155 interacts with the 3’UTR Ogn region and decrease the levels of Ogn in myotubes. The overexpression of miR-155 increased MyoG expression, decreased myoblasts wound closure rate, and decreased Myh2 expression in myotubes. Moreover, Ogn knockdown reduced the expression levels of MyoD, MyoG, and Myh2 in myotubes. These results reveal a novel pathway in which miR-155 inhibits Ogn expression to regulate proliferation and differentiation of C2C12 myoblast cells.

Neuromuscular junctions (NMJs): ultrastructural analysis and nicotinic acetylcholine receptor (nAChR) subunit mRNA expression in offspring subjected to protein restriction throughout pregnancy

Protein restriction during gestation can alter the skeletal muscle phenotype of offspring; however, little is known with regard to whether this also affects the neuromuscular junction (NMJ), as muscle phenotype maintenance depends upon NMJ functional integrity. This study aimed to evaluate the effects of a low protein (6%) intake by dams throughout gestation on male offspring NMJ morphology and nicotinic acetylcholine receptor (nAChR) α1, γ and ε subunit expression in the soleus (SOL) and extensor digitorum longus (EDL) muscles. Four groups of male Wistar offspring rats were studied. The offspring of dams fed low-protein (6% protein, LP) and normal protein (17% protein, NP) diets were evaluated at 30 and 120 days of age, and the SOL and EDL muscles were collected for analysis. Morphological studies using transmission electron microscopy revealed that only SOL NMJs were affected in 30-day-old offspring in the LP group compared with the NP group. SOL NMJs exhibited fewer synaptic folds, the postsynaptic membranes were smooth and myelin figures were also frequently observed in the terminal axons. With regard to the expression of mRNAs encoding nAChR subunits, only 30-day-old LP offspring EDL muscles exhibited reduced α, γ and ε subunit expression compared with the NP group. In conclusion, our results demonstrate that a low-protein diet (6%) imposed throughout pregnancy impairs the expression of mRNAs encoding the nAChR α, γ and ε subunits in EDL NMJs and promotes morphological changes in SOL NMJs of 30-day-old offspring, indicating specific differences among muscle types following long-term maternal protein restriction.

Food restriction increase the expression of mTORC1 complex genes in the skeletal muscle of juvenile pacu (Piaractus mesopotamicus)

Skeletal muscle is capable of phenotypic adaptation to environmental factors, such as nutrient availability, by altering the balance between muscle catabolism and anabolism that in turn coordinates muscle growth. Small noncoding RNAs, known as microRNAs (miRNAs), repress the expression of target mRNAs, and many studies have demonstrated that miRNAs regulate the mRNAs of catabolic and anabolic genes. We evaluated muscle morphology, gene expression of components involved in catabolism, anabolism and energetic metabolism and miRNAs expression in both the fast and slow muscle of juvenile pacu (Piaractus mesopotamicus) during food restriction and refeeding. Our analysis revealed that short periods of food restriction followed by refeeding predominantly affected fast muscle, with changes in muscle fiber diameter and miRNAs expression. There was an increase in the mRNA levels of catabolic pathways components (FBXO25, ATG12, BCL2) and energetic metabolism-related genes (PGC1α and SDHA), together with a decrease in PPARβ/δ mRNA levels. Interestingly, an increase in mRNA levels of anabolic genes (PI3K and mTORC1 complex: mTOR, mLST8 and RAPTOR) was also observed during food restriction. After refeeding, muscle morphology showed similar patterns of the control group; the majority of genes were slightly up- or down-regulated in fast and slow muscle, respectively; the levels of all miRNAs increased in fast muscle and some of them decreased in slow muscle. Our findings demonstrated that a short period of food restriction in juvenile pacu had a considerable impact on fast muscle, increasing the expression of anabolic (PI3K and mTORC1 complex: mTOR, mLST8 and RAPTOR) and energetic metabolism genes. The miRNAs (miR-1, miR-206, miR-199 and miR-23a) were more expressed during refeeding and while their target genes (IGF-1, mTOR, PGC1α and MAFbx), presented a decreased expression. The alterations in mTORC1 complex observed during fasting may have influenced the rates of protein synthesis by using amino acids from protein degradation as an alternative mechanism to preserve muscle phenotype and metabolic demand maintenance.

Training improves the oxidative phenotype of muscle during the transition from cardiac hypertrophy to heart failure without altering MyoD and myogenin

NEW FINDINGS

What is the central question of this study? We investigated the effects of physical training on phenotypic (fibre-type content) and myogenic features (MyoD and myogenin expression) in skeletal muscle during the transition from cardiac hypertrophy to heart failure. What is the main finding and its importance? We provide new insight into skeletal muscle adaptations by showing that physical training increases the type I fibre content during the transition from cardiac hypertrophy to heart failure, without altering MyoD and myogenin expression. These results have important clinical implications for patients with heart failure, because this population has reduced muscle oxidative capacity. The purpose of this study was to investigate the effects of physical training (PT) on phenotypic features (fibre-type content) and myogenic regulatory factors (MyoD and myogenin) in rat skeletal muscle during the transition from cardiac hypertrophy to heart failure. We used the model of ascending aortic stenosis (AS) to induce heart failure in male Wistar rats. Sham-operated animals were used as age-matched controls. At 18 weeks after surgery, rats with ventricular dysfunction were randomized into the following four groups: sham-operated, untrained (Sham-U; n = 8); sham-operated, trained (Sham-T; n = 6); aortic stenosis, untrained (AS-U; n = 6); and aortic stenosis, trained (AS-T; n = 8). The AS-T and Sham-T groups were submitted to a 10 week aerobic PT programme, while the AS-U and Sham-U groups remained untrained for the same period of time. After the PT programme, the animals were killed and the soleus muscles collected for phenotypic and molecular analyses. Physical training promoted type IIa-to-I fibre conversion in the trained groups (Sham-T and AS-T) compared with the untrained groups (Sham-U and AS-U). No significant (P > 0.05) differences were found in type I or IIa fibre content in the AS-U group compared with the Sham-U group. Additionally, there were no significant (P > 0.05) differences in the myogenic regulatory factors MyoD and myogenin (gene and protein) expression between the groups. Therefore, our results indicate that PT may be a suitable strategy to improve the oxidative phenotype in skeletal muscle during the transition from cardiac hypertrophy to heart failure, without altering MyoD and myogenin.

Preventive aerobic training exerts a cardioprotective effect on rats treated with monocrotaline

Pulmonary arterial hypertension (PAH) is a chronic disease which causes overload to the right ventricle. The effect of preventive training on cardiac remodelling in this condition is still unknown. This study aimed to evaluate the influence of preventive training on hypertrophy, heart function and gene expression of calcium transport proteins in rats with monocrotaline-induced PAH. Thirty-two male Wistar rats were randomly divided into four groups: S, sedentary control; T, trained control; SM, sedentary monocrotaline; and TM, trained monocrotaline. The preventive training protocol was performed on a treadmill for 13 weeks, five times/week. The first two weeks were adopted for adaptation to training with gradual increases in speed/time. The speed of the physical training from the third to tenth weeks was gradually increased from 0.9 to 1.1 km/h for 60 min. Next, monocrotaline was applied (60 mg/kg) to induce PAH and lactate threshold analysis performed to determine the training speeds. The training speed of the TM group in the following two weeks was 0.8 km/h for 60 min and the T = 0.9 km/h for 60 min; in the final two weeks, both groups trained at the same speed and duration 0.9 km/h, 60 min. Cardiac function was assessed through echocardiography, ventricular hypertrophy through histomorphometric analysis and gene expression through RT-qPCR. Right cardiac function assessed through the peak flow velocity was SM = 75.5 cm/s vs. TM = 92.0 cm/s (P = 0.001), and ventricular hypertrophy was SM = 106.4 μm² vs. TM = 77.7 μm² (P = 0.004). There was a decrease in the gene expression of ryanodine S = 1.12 au vs. SM = 0.60 au (P = 0.02) without alterations due to training. Thus, we conclude that prior physical training exerts a cardioprotective effect on the right ventricle in the monocrotaline rat model.

Fractal Dimension in Quantifying Experimental-Pulmonary-Hypertension-Induced Cardiac Dysfunction in Rats

BACKGROUND

Right-sided heart failure has high morbidity and mortality, and may be caused by pulmonary arterial hypertension. Fractal dimension is a differentiated and innovative method used in histological evaluations that allows the characterization of irregular and complex structures and the quantification of structural tissue changes.

OBJECTIVE

To assess the use of fractal dimension in cardiomyocytes of rats with monocrotaline-induced pulmonary arterial hypertension, in addition to providing histological and functional analysis.

METHODS

Male Wistar rats were divided into 2 groups: control (C; n = 8) and monocrotaline-induced pulmonary arterial hypertension (M; n = 8). Five weeks after pulmonary arterial hypertension induction with monocrotaline, echocardiography was performed and the animals were euthanized. The heart was dissected, the ventricles weighed to assess anatomical parameters, and histological slides were prepared and stained with hematoxylin/eosin for fractal dimension analysis, performed using box-counting method. Data normality was tested (Shapiro-Wilk test), and the groups were compared with non-paired Student t test or Mann Whitney test (p < 0.05).

RESULTS

Higher fractal dimension values were observed in group M as compared to group C (1.39 ± 0.05 vs. 1.37 ± 0.04; p < 0.05). Echocardiography showed lower pulmonary artery flow velocity, pulmonary acceleration time and ejection time values in group M, suggesting function worsening in those animals.

CONCLUSION

The changes observed confirm pulmonary-arterial-hypertension-induced cardiac dysfunction, and point to fractal dimension as an effective method to evaluate cardiac morphological changes induced by ventricular dysfunction.

β-ionone modulates the expression of miRNAs and genes involved in the metastatic phenotype of microdissected persistent preneoplastic lesions in rats submitted to hepatocarcinogenesis

MicroRNAs (miRNAs) are post-transcriptional gene expression regulators which expression is frequently altered in hepatocellular carcinoma (HCC). β-ionone (βI) is noted for its ability to inhibit persistent preneoplastic lesions (pPNLs) in liver rats. We evaluated the expression of miRNAs involved in carcinogenesis and possible targets modulated by βI, in pPNLs and surrounding of microdissected tissues. Rats subjected to resistant hepatocyte model were treated during promotion stage with βI (16 mg/100 g body weight) or corn oil (CO; 0.25 mL/100 g body weight; controls). Five animals receive no treatment (NT). In CO group, 38 and 29 miRNAs showed reduced expression relative to NT (P < 0.05) in pPNLs and surrounding, respectively. No miRNAs showed increased expression in surrounding of the CO compared to NT group; however, 30 miRNAs showed increased expression (P ≤ 0.05) in pPNLs of the CO group. There was no difference between βI and CO groups (P > 0.05) in the expression of miRNAs in surrounding. In pPNLs βI increased expression of miR-122 and miR-34a (P ≤ 0.05) and reduced of Igf2 (P ≤ 0.05), target of the latter, compared to CO. Additionally, βI decreased the expression of miR-181c and its target Gdf2 (P ≤ 0.05). βI reduced the expression of miR-181b and miR-708 (P ≤ 0.05) and increased the expression of their respective target mRNAs Timp3 and Mtss1 (P ≤ 0.05), relative to CO group. Modulation of miRNAs target genes by βI was confirmed in vitro. βI is a promising chemopreventive agent in the initial stages of hepatocarcinogenesis, as it modulates the expression of the miRNAs and target genes that can alter the metastatic phenotype of HCC. © 2016 Wiley Periodicals, Inc.

Differential microRNA Expression in Fast- and Slow-Twitch Skeletal Muscle of Piaractus mesopotamicus during Growth

Pacu (Piaractus mesopotamicus) is a Brazilian fish with a high economic value in pisciculture due to its rusticity and fast growth. Postnatal growth of skeletal muscle in fish occurs by hyperplasia and/or hypertrophy, processes that are dependent on the proliferation and differentiation of myoblasts. A class of small noncoding RNAs, known as microRNAs (miRNAs), represses the expression of target mRNAs, and many studies have demonstrated that miR-1, miR-133, miR-206 and miR-499 regulate different processes in skeletal muscle through the mRNA silencing of hdac4 (histone deacetylase 4), srf (serum response factor), pax7 (paired box 7) and sox6 ((sex determining region Y)-box 6), respectively. The aim of our work was to evaluate the expression of these miRNAs and their putative target mRNAs in fast- and slow-twitch skeletal muscle of pacu during growth. We used pacus in three different development stages: larval (aged 30 days), juvenile (aged 90 days and 150 days) and adult (aged 2 years). To complement our study, we also performed a pacu myoblast cell culture, which allowed us to investigate miRNA expression in the progression from myoblast proliferation to differentiation. Our results revealed an inverse correlation between the expression of the miRNAs and their target mRNAs, and there was evidence that miR-1 and miR-206 may regulate the differentiation of myoblasts, whereas miR-133 may regulate the proliferation of these cells. miR-499 was highly expressed in slow-twitch muscle, which suggests its involvement in the specification of the slow phenotype in muscle fibers. The expression of these miRNAs exhibited variations between different development stages and between distinct muscle twitch phenotypes. This work provides the first identification of miRNA expression profiles in pacu skeletal muscle and suggests an important role of these molecules in muscle growth and in the maintenance of the muscle phenotype.

Hyperproliferative action of bovine papillomavirus: genetic and histopathological aspects

The bovine papillomavirus (BPV) causes papillomas that regress spontaneously, but can also progress to malignancy. This study evaluated the role of BPV in oncogenesis. Twenty-four samples from uninfected calves and the papillomas of BPV infected cattle were subjected to molecular diagnosis, as well as histopathological and immunohistochemical analyses. The comet assay (CA) was used to evaluate the clastogenic potential of BPV. The results confirmed the presence of BPV-2, 3, 5, and 9 in infected samples. Histopathological analysis revealed acanthosis, koilocytosis, hypergranulosis, hyperkeratosis, and transformed fibroblasts.E7 and L1 BPV proteins were detected in the epithelium, as well as in the connective tissues, indicating productive infection at different sites. CA results showed that BPV-2, 5, and 9 exhibit the same level of clastogenicity. These findings support the oncogenic action of BPV in establishing a favorable microenvironment for oncogenesis.