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Background The repulsive guidance molecule a (RGMa) is a GPI-anchor axon guidance molecule first found to play important roles during neuronal development. RGMa expression patterns and signaling pathways via Neogenin and/or as BMP coreceptors indicated that this axon guidance molecule could also be working in other processes and diseases, including during myogenesis. Previous works from our research group have consistently shown that RGMa is expressed in skeletal muscle cells and that its overexpression induces both nuclei accretion and hypertrophy in muscle cell lineages. However, the cellular components and molecular mechanisms induced by RGMa during the differentiation of skeletal muscle cells are poorly understood. In this work, the global transcription expression profile of RGMa-treated C2C12 myoblasts during the differentiation stage, obtained by RNA-seq, were reported. Results RGMa treatment could modulate the expression pattern of 2,195 transcripts in C2C12 skeletal muscle, with 943 upregulated and 1,252 downregulated. Among them, RGMa interfered with the expression of several RNA types, including categories related to the regulation of RNA splicing and degradation. The data also suggested that nuclei accretion induced by RGMa could be due to their capacity to induce the expression of transcripts related to ‘adherens junsctions’ and ‘extracellular-cell adhesion’, while RGMa effects on muscle hypertrophy might be due to (i) the activation of the mTOR-Akt independent axis and (ii) the regulation of the expression of transcripts related to atrophy. Finally, RGMa induced the expression of transcripts that encode skeletal muscle structural proteins, especially from sarcolemma and also those associated with striated muscle cell differentiation. Conclusions These results provide comprehensive knowledge of skeletal muscle transcript changes and pathways in response to RGMa.

Electrospinning emerged as a promising technique to produce scaffolds for cultivated meat in function of its simplicity, versatility, cost-effectiveness, and scalability. Cellulose acetate (CA) is a biocompatible and low-cost material that support cell adhesion and proliferation. Here we investigated CA nanofibers, associated or not with a bioactive annatto extract (CA@A), a food-dye, as potential scaffolds for cultivated meat and muscle tissue engineering. The obtained CA nanofibers were evaluated concerning its physicochemical, morphological, mechanical and biological traits. UV-vis spectroscopy and contact angle measurements confirmed the annatto extract incorporation into the CA nanofibers and the surface wettability of both scaffolds, respectively. SEM images revealed that the scaffolds are porous, containing fibers with no specific alignment. Compared with the pure CA nanofibers, CA@A nanofibers showed increased fiber diameter (420 ± 212 nm vs. 284 ± 130 nm). Mechanical properties revealed that the annatto extract induces a reduction of the stiffness of the scaffold. Molecular analyses revealed that while CA scaffold favored C2C12 myoblast differentiation, the annatto-loaded CA scaffold favored a proliferative state of these cells. These results suggest that the combination of cellulose acetate fibers loaded with annatto extract may be an interesting economical alternative for support long-term muscle cells culture with potential application as scaffold for cultivated meat and muscle tissue engineering.

Limnoperna fortunei, the golden mussel, is a bivalve mollusk considered an invader in South America. This species is responsible for ecological and economic damages due to its voluminous fouling capability. Chemical biocides such as MXD-100™ and sodium dichloroisocyanurate (NaDCC) are often used to control L. fortunei infestations in hydraulic systems. Thus, we proposed to investigate the effects of different periods (24, 48 and 72 h) of exposure to MXD-100™ (0.56 mg L−1) and NaDCC (1.5 mg L−1) on the gills of L. fortunei through morphological and molecular analyses. NaDCC promoted progressive morphological changes during the analyzed periods and only an upregulation of SOD and HSP70 expression during the first 24 h of exposure. MXD-100™ led to severe morphological changes from the first period of exposure, in addition to an upregulation of SOD, CAT, HSP70 and CYP expression during the first 24 h. In contrast, MXD-100™ led to a downregulation of CAT transcription between 24 and 48 h. In static conditions, NaDCC causes lethal damage after 72 h of exposure, and that exposure needs to be continuous to achieve the control of the species. Meanwhile, the MXD-100™ treatment presented several effects during the first 24 h, showing acute toxicity in a shorter period of time.

The Repulsive Guidance Molecule a (RGMa) is a multifunctional GPI-anchored protein localized in the sarcolemma and sarcoplasm of the adult skeletal muscle cell. Our research group showed that RGMa overexpression can promote myoblast fusion and induce hypertrophic muscle fibers during in vitro differentiation. Here, we report that RGMa is expressed in primary skeletal muscle cells cultured in vitro, showing a nuclear localization, revealed by immunostaining with an antibody targeting its C-terminal region (C-RGMa). While RGMa was detected in the nuclei, its canonical receptor, Neogenin, was predominantly found in the perinuclear region. Nuclear RGMa was absent in Neogenin-knockdown cells, suggesting that Neogenin mediates its nuclear transport. Functional assays suggested that RGMa promotes primary skeletal muscle cell viability and proliferation and supports their myogenic commitment. These findings reveal a previously unrecognized nuclear function of RGMa–Neogenin signaling and provide new insights into the regulation of skeletal muscle cell behavior in vitro.

Ovarian puncture has been widely used in assisted reproduction, but there are still gaps about its effects on ovarian morphophysiology, as well as the relationship between inflammation caused by this procedure and the follicular growth and fertility. The aim of this study was to investigate the effects of ovarian puncture on folliculogenesis and fertility. Mice ( n  = 24) were divided into two groups: (1) SHAM—both ovaries were exposed and repositioned and (2) Punctured—ovaries were exposed, punctured, and repositioned. After 96 h of surgery, ovaries were collected for morphofunctional analysis. New females were used for the superovulation ( n  = 10) and fertility assays ( n  = 10). Increased volumetric density of inflammatory cells— p  = 0.0005, p  = 0.0013; hemorrhagic foci— p  < 0.0001; and inflammatory exudate— p  < 0.0001 could be noticed on the punctured group, compared to SHAM. The percentage of primordial follicles was lower on the punctured ovaries ( p  = 0.00294). Ovarian puncture has also induced an increase in the proliferation of granulosa cells of primary ( p  = 0.0321) and antral follicles ( p  = 0.0395), and an increased apoptotic index of antral follicles ( p  = 0.0100). There was no influence on expression of some genes related to inflammation, collagen deposition and folliculogenesis progression. The reproductive aspects (oocyte retrieval and number of fetuses per female) were not altered ( p  > 0.05). Taken together, our findings strongly suggest that ovarian puncture results in a local inflammation that affects follicular growth and atresia. However, it does not affect female fertility, which strengthens the safety of this procedure.

Among the invasive species known to occur in South America is the bivalve mollusc Limnoperna fortunei, whose presence is linked to several environmental and economic problems. Early detection and mitigation actions are needed to limit its impact in the remaining L. fortunei-free areas. PCR-based molecular methods have become the gold standard methodology for L. fortunei detection. However, PCR-based methods require complex logistics from field sampling to laboratory processing. Thus, the use of methods that can be directly applied in the field can speed up the detection process. This work aimed to establish, for the first time, the loop-mediated isothermal amplification (LAMP) method for the detection of L. fortunei, with perspectives for in situ application. A set of primers designed for LAMP was tested for amplification of DNA from L. fortunei adult tissues and environmental samples containing bivalve larvae. The test showed a limit of detection as low as 0.01 ng of DNA obtained from adult tissue samples and a minimum reaction time of 60 min. The set of primers used seems to be specific for L. fortunei, since there was no cross-amplification with other bivalve or invasive molluscs that co-occur with the golden mussel in the same environment. The LAMP technique also proved to be efficient in amplifying DNA derived from L. fortunei larvae, demonstrating it to be a robust method regarding potential environmental reaction inhibitors. Although the results obtained here were acquired under controlled laboratory conditions, the LAMP method is a promising tool to integrate L. fortunei invasion monitoring protocols.

Neurodegenerative disorders, including traumatic injuries to the central nervous system (CNS) and neurodegenerative diseases, are characterized by early axonal damage, which does not regenerate in the adult mammalian CNS, leading to permanent neurological deficits. One of the primary causes of the loss of regenerative ability is thought to be a developmental decline in neurons’ intrinsic capability for axon growth. Different molecules are involved in the developmental loss of the ability for axon regeneration, including many transcription factors. However, the function of microRNAs (miRNAs), which are also modulators of gene expression, in axon re-growth is still unclear. Among the various miRNAs recently identified with roles in the CNS, miR-17, which is highly expressed during early development, emerges as a promising target to promote axon regeneration. Here, we used adeno-associated viral (AAV) vectors to overexpress miR-17 (AAV.miR-17) in primary cortical neurons and evaluate its effects on neurite and axon regeneration in vitro. Although AAV.miR-17 had no significant effect on neurite outgrowth and arborization, it significantly enhances neurite regeneration after scratch lesion and axon regeneration after axotomy of neurons cultured in microfluidic chambers. Target prediction and functional annotation analyses suggest that miR-17 regulates gene expression associated with autophagy and cell metabolism. Our findings suggest that miR-17 promotes regenerative response and thus could mitigate neurodegenerative effects.

Although originally discovered inducing important biological functions in the nervous system, repulsive guidance molecule a (RGMa) has now been identified as a player in many other processes and diseases, including in myogenesis. RGMa is known to be expressed in skeletal muscle cells, from somites to the adult. Functional in vitro studies have revealed that RGMa overexpression could promote skeletal muscle cell hypertrophy and hyperplasia, as higher efficiency in cell fusion was observed. Here, we extend the potential role of RGMa during C2C12 cell differentiation in vitro. Our results showed that RGMa administrated as a recombinant protein during late stages of C2C12 myogenic differentiation could induce myoblast cell fusion and the downregulation of different myogenic markers, while its administration at early stages induced the expression of myogenic markers with no detectable morphological effects. We also found that RGMa effects on skeletal muscle hyperplasia are performed via neogenin receptor, possibly as part of a complex with other proteins. Additionally, we observed that RGMa-neogenin is not playing a role as an inhibitor of the BMP signalling in skeletal muscle cells. This work contributes to placing RGMa as a component of the mechanisms that determine skeletal cell fusion via neogenin receptor.

Limnoperna fortunei, known as the golden mussel, is an invasive bivalve in South America responsible for economic damages in hydroelectric plants due to its ability to attach and grow on the walls of water pipes and tubes. Chemical compounds are often used to control golden mussel infestations in water systems. Here, we investigated the effects of two biocides—MXD-100 ™ and sodium dichloroisocyanurate (NaDCC)—through the assessment of morphological and gene-expression alterations in the gills. Both biocides were able to modulate the expression of defensive genes and morphological changes. Yet, it seems that NaDCC needs continuous exposure to control golden mussel infestation, whereas MXD-100™ can inflict severe damage to the mussels in as little as 24 h. Our results can be used to enhance control strategies for managing mussel growth in water systems, simultaneously reducing the environmental impact associated with costly and harmful chemical releases. Limnoperna fortunei, the golden mussel, is a bivalve mollusk considered an invader in South America. This species is responsible for ecological and economic damages due to its voluminous fouling capability. Chemical biocides such as MXD-100™ and sodium dichloroisocyanurate (NaDCC) are often used to control L. fortunei infestations in hydraulic systems. Thus, we proposed to investigate the effects of different periods (24, 48 and 72 h) of exposure to MXD-100™ (0.56 mg L[sup.−1]) and NaDCC (1.5 mg L[sup.−1]) on the gills of L. fortunei through morphological and molecular analyses. NaDCC promoted progressive morphological changes during the analyzed periods and only an upregulation of SOD and HSP70 expression during the first 24 h of exposure. MXD-100™ led to severe morphological changes from the first period of exposure, in addition to an upregulation of SOD, CAT, HSP70 and CYP expression during the first 24 h. In contrast, MXD-100™ led to a downregulation of CAT transcription between 24 and 48 h. In static conditions, NaDCC causes lethal damage after 72 h of exposure, and that exposure needs to be continuous to achieve the control of the species. Meanwhile, the MXD-100™ treatment presented several effects during the first 24 h, showing acute toxicity in a shorter period of time.

Abstract The presence of follicles and the corpus luteum (CL) in the ovarian surface plays a key role in determining the morphological and molecular fate of the female reproductive tract. However, the specific response of the isthmus epithelium to these ovarian structures remains poorly understood. This study hypothesizes that distinct ovarian structures differentially affect both the cellular aggregate-forming capacity of oviductal isthmus cells and the expression of ESR1, ESR2, and PGR genes. Reproductive tracts were categorized into three groups: ovaries with ≤5 mm follicles (small follicles group; SF); ovaries with follicles between 8-10 mm (large follicles group; LF); and ovaries containing active corpus luteum (CL Group). Isthmus cells from the three groups were cultivated to form cellular aggregates (oviductal explants) during 24 h. Moreover, the expression levels of ESR1, ESR2, and PGR genes were analyzed in the isthmus cells of the experimental groups. The isthmus cells of LF group showed an increased number of cellular aggregates than SF and CL group. Additionally, the SF group presented more aggregates than the CL group. Gene expression analysis revealed that ESR1 expression was higher in the SF group than in the LF group. Moreover, PGR expression was greater in the CL than in the SF group, as well as in the LF than in the SF group. In conclusion, ovarian structures impact the cellular aggregate formation capacity and the gene expression of ovarian steroid receptors in isthmus cells.