There is an urgent need for drugs, therapies and vaccines to be available to protect the human population against COVID-19. One of the first approaches taken in the COVID-19 global response was to ...consider repurposing licensed drugs. This commentary highlights an extraordinary international collaborative effort of independent researchers who have recently all come to the same conclusion—that chloroquine or hydroxchloroquine are unlikely to provide clinical benefit against COVID-19.
One of the main hallmarks of Parkinson's disease (PD) is abnormal alpha-synuclein (α-syn) aggregation which forms the main component of intracellular Lewy body inclusions. This short report used ...preformed α-syn fibrils, as well as an A53T mutant α-syn adenovirus to mimic conditions of pathological protein aggregation in dopaminergic human derived SH-SY5Y neural cells. Since there is evidence that the mTOR pathway and glutamatergic signaling each influence protein aggregation, we also assessed the impact of the mTOR inhibitor, rapamycin and the mGluR5 allosteric modulator, CTEP. We found that both rapamycin and CTEP induced a significant reduction of α-syn fibrils in SH-SY5Y cells and this effect was associated with a reduction in mTOR signaling and enhancement in autophagic pathway factors. These data support the possibility that CTEP (or rapamycin) might be a useful pharmacological approach to target abnormal α-syn accumulation by promoting intracellular degradation or enhanced clearance.
Combined targeting of MAPK and PI3K signalling pathways may be necessary for optimal therapeutic activity in cancer. This study evaluated the MEK inhibitors AZD6244 and PD0325901, alone and in ...combination with the dual mTOR/PI3K inhibitor NVP-BEZ235 or the PI3K inhibitor GDC-0941, in three colorectal cancer cell lines.
Growth inhibition, survival and signal transduction were measured using the Sulforhodamine B assay, clonogenicity and western blotting, respectively, in HCT116, HT29 and DLD1 cell lines.
All MEK/PI3K inhibitor combinations exhibited marked synergistic growth inhibition; however, GDC-0941 displayed greater synergy in combination with either MEK inhibitor. NVP-BEZ235 exhibited stronger inhibition of 4EBP1 phosphorylation, and similar inhibition of S6 and AKT phosphorylation, compared with GDC-0941. Both PD0325901 and AZD6244 inhibited ERK phosphorylation, and with MEK/PI3K inhibitor combinations inhibition of S6 phosphorylation was increased. The reduced synergy exhibited by NVP-BEZ235 in combination with MEK inhibitors, compared with GDC-0941, may be due to inhibition of mTOR, and the addition of the mTORC1/2 inhibitor KU0063794 compromised the synergy of GDC-0941:PD0325901 combinations.
These studies confirm that dual targeting of PI3K and MEK can induce synergistic growth inhibition; however, the combination of specific PI3K inhibitors, rather than dual mTOR/PI3K inhibitors, with MEK inhibitors results in greater synergy.
Quantitative viral load assays have transformed our understanding of viral diseases. They hold similar potential to advance COVID-19 control and prevention, but SARS-CoV-2 viral load tests are not ...yet widely available. SARS-CoV-2 molecular diagnostic tests, which typically employ real-time RT-PCR, yield semiquantitative results only. Droplet digital RT-PCR (RT-ddPCR) offers an attractive platform for SARS-CoV-2 RNA quantification. Eight primer/probe sets originally developed for real-time RT-PCR–based SARS-CoV-2 diagnostic tests were evaluated for use in RT-ddPCR; three were identified as the most efficient, precise, and sensitive for RT-ddPCR–based SARS-CoV-2 RNA quantification. For example, the analytical efficiency for the E-Sarbeco primer/probe set was approximately 83%, whereas assay precision, measured as the coefficient of variation, was approximately 2% at 1000 input copies/reaction. Lower limits of quantification and detection for this primer/probe set were 18.6 and 4.4 input SARS-CoV-2 RNA copies/reaction, respectively. SARS-CoV-2 RNA viral loads in a convenience panel of 48 COVID-19–positive diagnostic specimens spanned a 6.2log10 range, confirming substantial viral load variation in vivo. RT-ddPCR–derived SARS-CoV-2 E gene copy numbers were further calibrated against cycle threshold values from a commercial real-time RT-PCR diagnostic platform. This log-linear relationship can be used to mathematically derive SARS-CoV-2 RNA copy numbers from cycle threshold values, allowing the wealth of available diagnostic test data to be harnessed to address foundational questions in SARS-CoV-2 biology.
Abstract
Background
Cardiorespiratory fitness and perceived fatigability are interrelated components of physical capacity that may jointly influence movement within one’s living environment ...(life-space mobility). We examined whether fitness and fatigability were associated with life-space mobility in community-dwelling older adults, and whether the association of fitness with life-space varied by the level of perceived fatigability.
Methods
Participants were from the Study of Muscle, Mobility and Aging (SOMMA) baseline cohort (N = 775, mean age 76.1 years). Life Space Assessment scores incorporated level, frequency, and assistance used (personal, devices) for life-space mobility. Fitness was measured as VO2peak from symptom-limited treadmill testing. Fatigability cut-points included: (i) Borg Rating of Perceived Exertion (RPE) ≥ 10 after a fixed-speed (1.5 mph) treadmill test, (ii) the Pittsburgh Fatigability Scale (PFS) Physical ≥ 15, and (iii) PFS Mental ≥ 13. The total count of cut-points was used as a composite fatigability measure (range: 0–3). Linear regressions were adjusted for demographic, lifestyle, and health confounders.
Results
Better fitness was associated with greater life-space, but the association plateaued at higher fitness levels (VO2peak > 18). Life-space was significantly lower for individuals meeting ≥2 fatigability criteria (vs none), attributable mainly to more severe physical, but not mental, fatigability. In moderation analyses, the fitness–life-space association was significant only for those with RPE ≥ 10 but did not differ by PFS.
Conclusion
Fitness below a critically low threshold was associated with limited life-space mobility, suggesting that certain older individuals may need to operate close to their maximum aerobic capacity to traverse daily environments; these associations were driven by those with more severe physical fatigability.
The Pittsburgh Performance Fatigability Index (PPFI) quantifies the percent decline in cadence using accelerometry during standardized walking tasks. Although PPFI has shown strong correlations with ...physical performance, the developmental sample was relatively homogenous and small, necessitating further validation.
Participants from the Study of Muscle, Mobility and Aging (N = 805, age = 76.4 ± 5.0 years, 58% women, 85% White) wore an ActiGraph GT9X on the nondominant wrist during usual-paced 400 m walk. Tri-axial accelerations were analyzed to compute PPFI (higher score = greater fatigability). To evaluate construct and discriminant validity, Spearman correlations (rs) between PPFI and gait speed, Short Physical Performance Battery (SPPB), chair stand speed, leg peak power, VO2peak, perceived fatigability, and mood were examined. Sex-specific PPFI cut-points that optimally discriminated gait speed using classification and regression tree were then generated. Their discriminate power in relation to aforementioned physical performance were further evaluated.
Median PPFI score was 1.4% (25th-75th percentile range: 0%-21.7%), higher among women than men (p < .001). PPFI score was moderate-to-strongly correlated with gait speed (rs = -0.75), SPPB score (rs = -0.38), chair stand speed (rs = -0.36), leg peak power (rs = -0.34) and VO2peak (rs = -0.40), and less strongly with perceived fatigability (rs = 0.28-0.29), all p < .001. PPFI score was not correlated with mood (|rs| < 0.08). Sex-specific PPFI cut-points (no performance fatigability: PPFI = 0%; mild performance fatigability: 0% < PPFI < 3.5% women, 0% < PPFI < 5.4% men; moderate-to-severe performance fatigability: PPFI ≥ 3.5% women, PPFI ≥ 5.4% men) discriminated physical performance (all p < .001), adjusted for demographics and smoking status.
Our work underscores the utility of PPFI as a valid measure to quantify performance fatigability in future longitudinal epidemiologic studies and clinical/pharmaceutical trials.
Marine recruits training at Parris Island experienced an unexpectedly high rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, despite preventive measures including a ...supervised, 2-week, pre-entry quarantine. We characterize SARS-CoV-2 transmission in this cohort.
Between May and November 2020, we monitored 2,469 unvaccinated, mostly male, Marine recruits prospectively during basic training. If participants tested negative for SARS-CoV-2 by quantitative polymerase chain reaction (qPCR) at the end of quarantine, they were transferred to the training site in segregated companies and underwent biweekly testing for 6 weeks. We assessed the effects of coronavirus disease 2019 (COVID-19) prevention measures on other respiratory infections with passive surveillance data, performed phylogenetic analysis, and modeled transmission dynamics and testing regimens.
Preventive measures were associated with drastically lower rates of other respiratory illnesses. However, among the trainees, 1,107 (44.8%) tested SARS-CoV-2-positive, with either mild or no symptoms. Phylogenetic analysis of viral genomes from 580 participants revealed that all cases but one were linked to five independent introductions, each characterized by accumulation of mutations across and within companies, and similar viral isolates in individuals from the same company. Variation in company transmission rates (mean reproduction number R 0 ; 5.5 95% confidence interval CI, 5.0, 6.1) could be accounted for by multiple initial cases within a company and superspreader events. Simulations indicate that frequent rapid-report testing with case isolation may minimize outbreaks.
Transmission of wild-type SARS-CoV-2 among Marine recruits was approximately twice that seen in the community. Insights from SARS-CoV-2 outbreak dynamics and mutations spread in a remote, congregate setting may inform effective mitigation strategies.
Background
Men who have sex with men (MSM) are at risk for sexually‐transmitted hepatitis C (HCV). Evidence for HCV infection in the context of pre‐exposure prophylaxis (PrEP) use in North America is ...limited. We sought to characterize baseline HCV prevalence and incidence in MSM receiving PrEP in British Columbia (BC), Canada.
Methods
We followed individuals in the BC PrEP program from January 2018 to August 2019. We evaluated baseline prevalence and incident seroconversions (newly positive HCV antibody). A multivariable logistic regression model was performed in MSM for factors associated with HCV prevalence at enrollment, including reported prior sexually transmitted infection (STI), HIV Incidence Risk Index for MSM score, PrEP use because of a partner living with HIV, and location of residence.
Results
The median age of the cohort was 33 years, 98.3% male, with 3058 person years (PY) of follow‐up. Baseline HCV prevalence was 0.82% (31/3907 MSM enrollees) and HCV incidence (n = 3) was 0.15 per 100 PY (95% confidence interval CI 0.03–0.45). In multivariable analysis, initiating PrEP because of a partner living with HIV (adjusted odds ratio aOR 5.02; 95% CI 1.87–13.47) and prior STI (aOR 2.34; 95% CI 1.04–5.24) were associated with positive HCV status.
Conclusions
Baseline HCV prevalence and incidence was low amongst MSM in a population‐based PrEP program in BC, Canada. HCV was associated with bridging from populations living with HIV and evidence of a reported prior STI as a PrEP indicator condition amongst MSM. PrEP initiation may be an opportunity for linkage to HCV screening and treatment.
Parkinson’s disease is a neurodegenerative disease characterized by a loss of dopaminergic substantia nigra neurons and depletion of dopamine. To date, current therapeutic approaches focus on ...managing motor symptoms and trying to slow neurodegeneration, with minimal capacity to promote neurorecovery. mGluR5 plays a key role in neuroplasticity, and altered mGluR5 signaling contributes to synucleinopathy and dyskinesia in patients with Parkinson’s disease. Here, we tested whether the mGluR5-negative allosteric modulator, (2-chloro-4-22,5-dimethyl-1-4-(trifluoromethoxy) phenyl imidazol-4-yl ethynyl pyridine (CTEP), would be effective in improving motor deficits and promoting neural recovery in a 6-hydroxydopamine (6-OHDA) mouse model. Lesions were induced by 6-ODHA striatal infusion, and 30 days later treatment with CTEP (2 mg/kg) or vehicle commenced for either 1 or 12 weeks. Animals were subjected to behavioral, pathological, and molecular analyses. We also assessed how long the effects of CTEP persisted, and finally, using rapamycin, determined the role of the mTOR pathway. CTEP treatment induced a duration-dependent improvement in apomorphine-induced rotation and performance on rotarod in lesioned mice. Moreover, CTEP promoted a recovery of striatal tyrosine hydroxylase-positive fibers and normalized FosB levels in lesioned mice. The beneficial effects of CTEP were paralleled by an activation of mammalian target of rapamycin (mTOR) pathway and elevated brain-derived neurotrophic factor levels in the striatum of lesioned mice. The mTOR inhibitor, rapamycin (sirolimus), abolished CTEP-induced neurorecovery and rescue of motor deficits. Our findings indicate that mTOR pathway is a useful target to promote recovery and that mGluR5 allosteric regulators may potentially be repurposed to selectively target this pathway to enhance neuroplasticity in patients with Parkinson’s disease.
Cities can host significant biological diversity. Yet, urbanisation leads to the loss of habitats, species, and functional groups. Understanding how multiple taxa respond to urbanisation globally is ...essential to promote and conserve biodiversity in cities. Using a dataset encompassing six terrestrial faunal taxa (amphibians, bats, bees, birds, carabid beetles and reptiles) across 379 cities on 6 continents, we show that urbanisation produces taxon-specific changes in trait composition, with traits related to reproductive strategy showing the strongest response. Our findings suggest that urbanisation results in four trait syndromes (mobile generalists, site specialists, central place foragers, and mobile specialists), with resources associated with reproduction and diet likely driving patterns in traits associated with mobility and body size. Functional diversity measures showed varied responses, leading to shifts in trait space likely driven by critical resource distribution and abundance, and taxon-specific trait syndromes. Maximising opportunities to support taxa with different urban trait syndromes should be pivotal in conservation and management programmes within and among cities. This will reduce the likelihood of biotic homogenisation and helps ensure that urban environments have the capacity to respond to future challenges. These actions are critical to reframe the role of cities in global biodiversity loss.
PDF
