DDX3X overexpression decreases dipeptide repeat proteins in a mouse model of C9ORF72-ALS/FTD.

Hexanucleotide repeat expansion in C9ORF72 (C9) is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). One of the proposed pathogenic mechanisms is the neurotoxicity arising from dipeptide repeat (DPR) proteins produced by repeat-associated non-AUG (RAN) translation. Therefore, reducing DPR levels emerges as a potential therapeutic strategy for C9ORF72-ALS/FTD. We previously identified an RNA helicase, DEAD-box helicase 3 X-linked (DDX3X), modulates RAN translation. DDX3X overexpression decreases poly-GP accumulation in C9ORF72-ALS/FTD patient-derived induced pluripotent stem cell (iPSC)-differentiated neurons (iPSNs) and reduces the glutamate-induced neurotoxicity. In this study, we examined the in vivo efficacy of DDX3X overexpression using a mouse model. We expressed exogenous DDX3X or GFP in the central nervous system (CNS) of the C9-500 ALS/FTD BAC transgenic or non-transgenic control mice using adeno-associated virus serotype 9 (AAV9). The DPR levels were significantly reduced in the brains of DDX3X-expressing C9-BAC mice compared to the GFP control even twelve months after virus delivery. Additionally, p62 aggregation was also decreased. No neuronal loss or neuroinflammatory response were detected in the DDX3X overexpressing C9-BAC mice. This work demonstrates that DDX3X overexpression effectively reduces DPR levels in vivo without provoking neuroinflammation or neurotoxicity, suggesting the potential of increasing DDX3X expression as a therapeutic strategy for C9ORF72-ALS/FTD.

Could Microplastics Be a Driver for Early Onset Colorectal Cancer?

Introduction: The incidence of colorectal cancer in those under 50 years of age (early onset colorectal cancer (EOCRC)) is increasing throughout the world. This has predominantly been an increase in distal colonic and rectal cancers, which are biologically similar to late onset colorectal cancer (LOCRC) but with higher rates of mucinous or signet ring histology, or poorly differentiated cancers. The epidemiology of this change suggests that it is a cohort effect since 1960, and is most likely driven by an environmental cause. We explore the possible role of microplastics as a driver for this change. Review: The development of sporadic colorectal cancer is likely facilitated by the interaction of gut bacteria and the intestinal wall. Normally, a complex layer of luminal mucus provides colonocytes with a level of protection from the effects of these bacteria and their toxins. Plastics were first developed in the early 1900s. After 1945 they became more widely used, with a resultant dramatic increase in plastic pollution and their breakdown to microplastics. Microplastics (MPs) are consumed by humans from an early age and in increasingly large quantities. As MPs pass through the gastrointestinal tract they interact with the normal physiological mechanism of the body, particularly in the colon and rectum, where they may interact with the protective colonic mucus layer. We describe several possible mechanisms of how microplastics may disrupt this mucus layer, thus reducing its protective effect and increasing the likelihood of colorectal cancer. Conclusions: The epidemiology of increase in EOCRC suggests an environmental driver. This increase in EOCRC matches the time sequence in which we could expect to see an effect of rapid increase of MPs in the environment and, as such, we have explored possible mechanisms for this effect. We suggest that it is possible that the MPs damage the barrier integrity of the colonic mucus layer, thus reducing its protective effect. MPs in CRC pathogenesis warrants further investigation. Future directions: Further clarification needs to be sought regarding the interaction between MPs, gut microbiota and the mucus layer. This will need to be modelled in long-term animal studies to better understand how chronic consumption of environmentally-acquired MPs may contribute to an increased risk of colorectal carcinogenesis.

Measuring Substance-Related Disorders Using Canadian Administrative Health Databanks: Interprovincial Comparisons of Recorded Diagnostic Rates, Incidence Proportions and Mortality Rate Ratios.

CONTEXT: Assessing temporal changes in the recorded diagnostic rates, incidence proportions, and health outcomes of substance-related disorders (SRD) can inform public health policymakers in reducing harms associated with alcohol and other drugs. OBJECTIVE: To report the annual and cumulative recorded diagnostic rates and incidence proportions of SRD, as well as mortality rate ratios (MRRs) by cause of death among this group in Canada, according to their province of residence. METHODS: Analyses were performed on linked administrative health databases (AHD; physician claims, hospitalizations, and vital statistics) in five Canadian provinces (Alberta, Manitoba, Ontario, Québec, and Nova Scotia). Canadians 12 years and older and registered for their provincial healthcare coverage were included. The International Classification of Diseases (ICD-9 or ICD-10 codes) was used for case identification of SRD from April 2001 to March 2018. RESULTS: During the study period, the annual recorded SRD diagnostic rates increased in Alberta (2001-2002: 8.0‰; 2017-2018: 12.8‰), Ontario (2001-2002: 11.5‰; 2017-2018: 14.4‰), and Nova Scotia (2001-2002: 6.4‰; 2017-2018: 12.7‰), but remained stable in Manitoba (2001-2002: 5.5‰; 2017-2018: 5.4‰) and Québec (2001-2002 and 2017-2018: 7.5‰). Cumulative recorded SRD diagnostic rates increased steadily for all provinces. Recorded incidence proportions increased significantly in Alberta (2001-2002: 4.5‰; 2017-2018: 5.0‰) and Nova Scotia (2001-2002: 3.3‰; 2017-2018: 3.8‰), but significantly decreased in Ontario (2001-2002: 6.2‰; 2017-2018: 4.7‰), Québec (2001-2002: 4.1‰; 2017-2018: 3.2‰) and Manitoba (2001-2002: 2.7‰; 2017-2018: 2.0‰). For almost all causes of death, a higher MRR was found among individuals with recorded SRD than in the general population. The causes of death in 2015-2016 with the highest MRR for SRD individuals were SRD, suicide, and non-suicide trauma in Alberta, Ontario, Manitoba, and Québec. DISCUSSION: Linked AHD covering almost the entire population can be useful to monitor the medical service trends of SRD and, therefore, guide health services planning in Canadian provinces.

Highly effective fibrinolysis by a sequential synergistic combination of mini-dose tPA plus low-dose mutant proUK.

Results of thrombolysis by monotherapy with either tPA or proUK have not lived up to expectations. Since these natural activators are inherently complementary, this property can be utilized to a synergistic advantage; and yet, this has undergone little evaluation. ProUK is no longer available because at pharmacological concentrations it converts to UK in plasma. Therefore, a single site proUK mutant, M5, was developed to address this problem and was used in this study. Fibrinolysis was measured using preformed fluoresceinated 24 h old clots in a plasma milieu rather than by the standard automated method, because proUK/M5 is sensitive to inactivation by thrombin and activation by plasmin. The shortest 50% clot lysis time that could be achieved by tPA or M5 alone was determined: mean times were 55 and 48 minutes respectively. These bench marks were matched by 6% of the tPA monotherapy dose combined with 40% that of M5: mean lysis time 47 minutes with less associated fibrinogenolysis. Results showed that the tPA effect was limited to initiating fibrinolysis which was completed by M5 and then tcM5. Plasma C1-inhibitor inhibited fibrinogenolysis by M5, providing protection from side effects not available for proUK. In conclusion, by utilizing the complementary properties and sequential modes of action of each activator, more efficient fibrinolysis with less non-specific effects can be achieved than with traditional monotherapy. In vivo validation is needed, but in a previous clinical trial using a similar combination of tPA and proUK (5% and 50% monotherapy doses) very promising results have already been obtained.