Loss of miR-210 leads to progressive retinal degeneration in Drosophila melanogaster.

miRNAs are small, non-coding RNAs that regulate gene expression post-transcriptionally. We used small RNA sequencing to identify tissue-specific miRNAs in the adult brain, thorax, gut, and fat body of Drosophila melanogaster One of the most brain-specific miRNAs that we identified was miR-210, an evolutionarily highly conserved miRNA implicated in the regulation of hypoxia in mammals. In Drosophila, we show that miR-210 is specifically expressed in sensory organs, including photoreceptors. miR-210 knockout mutants are not sensitive toward hypoxia but show progressive degradation of photoreceptor cells, accompanied by decreased photoreceptor potential, demonstrating an important function of miR-210 in photoreceptor maintenance and survival.

Decision to Return to Sport Participation After Anterior Cruciate Ligament Reconstruction, Part II: Self-Reported and Functional Performance Outcomes.

CONTEXT: Anterior cruciate ligament (ACL) reconstruction (ACLR) is the most commonly used method for helping athletes regain function and return to preinjury activity levels after ACL injury. Outcomes after ACLR have suggested that athletes return to a level of function that would support a return to sport participation; however, in a recent meta-analysis, pooled return rates were only 55%. It is unclear whether this discrepancy is a result of functional impairments. OBJECTIVE: To compare patient-reported outcomes (PROs), dynamic balance, dynamic functional performance, strength, and muscular endurance in athletes who returned to sport (RTS) and athletes who did not return to sport (NRTS) after ACLR. DESIGN: Case-control study. SETTING: University research laboratory. PATIENTS OR OTHER PARTICIPANTS: Two groups of participants with primary unilateral ACLR: 18 RTS individuals (7 males, 11 females; age = 23 ± 11 years, height = 163.58 ± 40.41 cm, mass = 70.00 ± 21.75 kg, time since surgery = 4.02 ± 3.20 years) and 12 NRTS individuals (5 males, 7 females; age = 26 ± 13 years, height = 171.33 ± 48.24 cm, mass = 72.00 ± 21.81 kg, time since surgery = 3.68 ± 2.71 years). INTERVENTION(S): The PROs consisted of the International Knee Documentation Committee Subjective Knee Evaluation Form, Knee Injury and Osteoarthritis Outcome Score, Tegner Activity Scale, and Marx Activity Scale. Functional performance outcome measures were the anterior and posteromedial reach on the Star Excursion Balance Test, a battery of single-legged-hop tests, isokinetic quadriceps and hamstrings strength at 60°/s and 180°/s, and a novel step-down-to-fatigue test. All measures were taken during a single laboratory session. MAIN OUTCOME MEASURE(S): The Limb Symmetry Index was calculated for all functional performance measures. Mann-Whitney U tests were used to compare measures between groups ( P < .10). RESULTS: Compared with the RTS group, the NRTS group had lower scores on the International Knee Documentation Committee Subjective Knee Evaluation Form (RTS median = 92.52, range = 66.67-97.70; NRTS median = 82.76, range = 63.22-96.55; P = .03) and Knee Injury and Osteoarthritis Outcome Score Symptoms subscale (RTS median = 88, range = 54-100; NRTS median = 71, range = 54-100; P = .08). No differences were observed for any functional performance measures. CONCLUSIONS: The NRTS athletes displayed lower PROs despite demonstrating similar function on a variety of physical performance measures. These results further support existing evidence that physical performance alone may not be the ideal postoperative outcome measure. Measures of patients' symptoms and self-perceived physical function may also greatly influence postoperative activity choices.

Decision to Return to Sport After Anterior Cruciate Ligament Reconstruction, Part I: A Qualitative Investigation of Psychosocial Factors.

CONTEXT: Return-to-sport criteria after anterior cruciate ligament (ACL) injury are often based on "satisfactory" functional and patient-reported outcomes. However, an individual's decision to return to sport is likely multifactorial; psychological and physical readiness to return may not be synonymous. OBJECTIVE: To determine the psychosocial factors that influence the decision to return to sport in athletes 1 year post-ACL reconstruction (ACLR). DESIGN: Qualitative study. SETTING: Academic medical center. PATIENTS OR OTHER PARTICIPANTS: Twelve participants (6 males, 6 females) were purposefully chosen from a large cohort. Participants were a minimum of 1-year postsurgery and had been active in competitive athletics preinjury. DATA COLLECTION AND ANALYSIS: Data were collected via semistructured interviews. Qualitative analysis using a descriptive phenomenologic process, horizontalization, was used to derive categories and themes that represented the data. The dynamic-biopsychosocial model was used as a theoretical framework to guide this study. RESULTS: Six predominant themes emerged that described the participants' experiences after ACLR: (1) hesitation and lack of confidence led to self-limiting tendencies, (2) awareness was heightened after ACLR, (3) expectations and assumptions about the recovery process influenced the decision to return to sport after ACLR, (4) coming to terms with ACL injury led to a reprioritization, (5) athletic participation helped reinforce intrinsic personal characteristics, and (6) having a strong support system both in and out of rehabilitation was a key factor in building a patient's confidence. We placed themes into components of the dynamic-biopsychosocial model to better understand how they influenced the return to sport. CONCLUSIONS: After ACLR, the decision to return to sport was largely influenced by psychosocial factors. Factors including hesitancy, lack of confidence, and fear of reinjury are directly related to knee function and have the potential to be addressed in the rehabilitation setting. Other factors, such as changes in priorities or expectations, may be independent of physical function but remain relevant to the patient-clinician relationship and should be considered during postoperative rehabilitation.

Deletion of endogenous Tau proteins is not detrimental in Drosophila.

Human Tau (hTau) is a highly soluble and natively unfolded protein that binds to microtubules within neurons. Its dysfunction and aggregation into insoluble paired helical filaments is involved in the pathogenesis of Alzheimer's disease (AD), constituting, together with accumulated ß-amyloid (Aß) peptides, a hallmark of the disease. Deciphering both the loss-of-function and toxic gain-of-function of hTau proteins is crucial to further understand the mechanisms leading to neurodegeneration in AD. As the fruit fly Drosophila melanogaster expresses Tau proteins (dTau) that are homologous to hTau, we aimed to better comprehend dTau functions by generating a specific tau knock-out (KO) fly line using homologous recombination. We observed that the specific removal of endogenous dTau proteins did not lead to overt, macroscopic phenotypes in flies. Indeed, survival, climbing ability and neuronal function were unchanged in tau KO flies. In addition, we did not find any overt positive or negative effect of dTau removal on human Aß-induced toxicity. Altogether, our results indicate that the absence of dTau proteins has no major functional impact on flies, and suggests that our tau KO strain is a relevant model to further investigate the role of dTau proteins in vivo, thereby giving additional insights into hTau functions.