Senegalese sole (Solea senegalensis) is a species with a high commercial value that exhibits a reproductive dysfunction in males born and raised in captivity (F1) that hinders their sustainable culture. The present study evaluates the sperm quality and dopaminergic pathway of males born in the wild environment and of F1 males. Traditional sperm analyses were performed, finding only significant differences in curvilinear velocity (VCL) and no significant differences in viability and total motility. No differences in global sperm methylation were observed either in spermatozoa or brain between the two groups (F1 and wild-born males). However, our results point to a different sperm molecular signature between wild fish and fish born in captivity, specifically the differential expression in miR-let7-d and miR-200a-5p between these two groups. miR-let7-d has been correlated with spermatogenesis and sex preferences, whereas the miR-200 family is implied in target innervation of dopaminergic neurons in zebrafish. When we analysed the dopaminergic pathway, no differences were found in terms of different mRNA expression of dopaminergic markers. However, some differences were detected in terms of tyrosine hydroxylase protein expression by western blot analysis, thus suggesting an altered post-transcriptional regulation in F1 males. The results of this study suggest that an altered sperm miRNA signature in F1 males could be one possible mode of transmission of reproductive dysfunction to the progeny.

Ubiquitination of the TrkA neurotrophin receptor in response to NGF is critical in the regulation of TrkA activation and its functions. TrkA is ubiquitinated among other E3 ubiquitin ligases by Nedd4-2. To understand mechanistically how TrkA ubiquitination is regulated, we performed a siRNA screening to identify deubiquitinating enzymes and found that USP36 acts as an important regulator of TrkA activation kinetics and ubiquitination. However, USP36 action on TrkA was indirect since it does not deubiquitinate TrkA. Instead, USP36 binds to Nedd4-2 and regulates the association of TrkA and Nedd4-2. In addition, depletion of USP36 increases TrkA-Nedd4-2 complex formation whereas USP36 expression disrupts the complex resulting in an enhancement or impairment of Nedd4-2-dependent TrkA ubiquitination, respectively. Moreover, USP36 depletion leads to enhanced total and surface TrkA expression that results in increased NGF-mediated TrkA activation and signalling that augments PC12 cell differentiation. USP36 actions extend beyond TrkA since the presence of USP36 interferes with Nedd4-2-dependent Kv7.2/3 channel regulation. Our results demonstrate that USP36 binds to and regulates the actions of Nedd4-2 over different substrates affecting their expression and functions.

Dry eye disease (DED) is a prevalent condition characterized by ocular surface inflammation and pain. This study evaluated the long-term progression of DED by analyzing clinical and molecular status, considering the impact of chronic ocular pain. Patients with DED were evaluated at two visits (V1 and V2) separated by at least two years. Evaluations included validated symptom questionnaires alongside slit-lamp examination, corneal sensitivity testing, and sub-basal nerve plexus analysis. Basal tear samples were collected for multiplex quantification of 20 cytokines and substance P (SP), and conjunctival cells were obtained to analyze 25 genes and 12 microRNAs (miRNA). Based on the presence or absence of chronic ocular pain, patients were then divided into two groups. Patients improved in DED-related symptoms, with no changes observed in ocular surface signs. Corneal dendritic cell density decreased, along with epidermal growth factor (EGF), fractalkine, and monocyte chemoattractant protein (MCP-1) tear levels, whereas interleukin (IL)-10 and SP tear levels increased. Neurotrophic tyrosine kinase, receptor, type (NTRK)1 gene expression was significantly downregulated, especially in patients without chronic ocular pain. miR-665 expression decreased significantly in DED patients. Monitoring corneal dendritic cells, tear cytokines, and gene/miRNA expression offers promising tools for tracking DED progression. Distinguishing the presence of chronic ocular pain as a separate symptom is crucial to optimizing therapeutic strategies and DED progression.

To analyze changes in tear levels of inflammatory mediators in symptomatic contact lens (CL) wearers after refitting with daily disposable CLs and to identify potential biomarkers of success in CL discomfort (CLD) management. Symptomatic CL wearers (CLDEQ-8 ≥ 12) were refitted (V1) with daily disposable CLs (Delefilcon A). After one month (V2), participants were classified into the post-fitting non-symptomatic (CLDEQ <12) and symptomatic (CLDEQ ≥12) groups. At each visit, the participants were clinically evaluated, tears were collected, and 20 inflammatory mediators and substance P (SP) were measured using multiplex immunobead analysis and ELISA, respectively. The detection rates and concentrations were compared between visits and groups, and logistic regression models were performed. Forty-three subjects (32 women/11 men; mean age: 23.2 ± 4.9 years) were enrolled. The IL-1β and IL-9 detection rates were higher at V2 (p ≤ 0.044). The detection rates of IL-1β, IL-9, MIP-1α/CCL3, and MMP-9 at V1 (p ≤ 0.045) and IL-17A at V2 (p ≤ 0.014) were higher in the post-fitting symptomatic group. The tear IL-9 concentration was increased at V2 (p = 0.018). The tear concentrations of fractalkine/CX3CL1, IL-2, IL-6, IL-10, MCP-3/CCL7, MIP-1β, NGF, RANTES/CCL5, and TNF-α were higher in the post-fitting symptomatic group (p ≤ 0.044). Additionally, levels of fractalkine/CX3CL1, IL-2, IL-6, IL-10, RANTES/CCL5, and TNF-α at V1 were significantly associated with the post-fitting grouping (p ≤ 0.044). Low tear concentrations of specific inflammatory mediators may be used as a predictive biomarker of success for refitting symptomatic CL wearers with daily disposable CLs. However, complementary treatments might be required for symptomatic CL wearers with higher levels of these inflammatory molecules.

The cytoskeleton relies heavily on the dynamic nature of microtubules, regulated by post-translational modifications such as polyglutamylation and deglutamylation. Disruption of its internal balance, particularly through the absence of cytosolic carboxypeptidase 1 (CCP1), leads to cytoskeletal collapse and cell death. An example of this occurrence exists in the Purkinje Cell Degeneration (PCD) mouse, a direct animal model for childhood-onset neurodegeneration with cerebellar atrophy (CONDCA) human disease. Both CONDCA patients and PCD mice suffer a dramatic degeneration of Purkinje cells. Intriguingly, lobe X appears less vulnerable to this insult. This study revealed in wild-type mice that lobe X expresses less Ccp1 compared to other lobes, correlating with its delayed degeneration in PCD mice. Further expression analysis of other deglutamylating enzymes (CCP4 and CCP6) and glutamylating enzymes (TTLL1) revealed distinctive patterns: Ccp4 showed minimal relevance in cerebellum, while Ccp6 displayed a compensatory increase during critical stages. Meanwhile, Ttll1 expression remained consistent across lobes, suggesting that the resistance of lobe X may be related to a more dynamic, hyperglutamylated cytoskeleton. Unraveling the neuroresistance mechanisms of Purkinje cells may help mitigate neuronal loss in CONDCA patients and may offer a glimmer of hope for alleviating the symptoms of other neurodegenerative diseases.