Novel STMN2 Variant Linked to Amyotrophic Lateral Sclerosis Risk and Clinical Phenotype

Objective

There is a critical need to establish genetic markers that explain the complex phenotypes and pathogenicity of ALS. This study identified a polymorphism in the Stathmin-2 gene and investigated its association with sporadic ALS (sALS) disease risk, age-of onset and survival duration.

Methods

The candidate CA repeat was systematically analyzed using PCR, Sanger sequencing and high throughput capillary separation for genotyping. Stathmin-2 expression was investigated using RT-PCR in patient olfactory neurosphere-derived (ONS) cells and RNA sequencing in laser-captured spinal motor neurons.

Results

In a case-control analysis of a combined North American sALS cohort (n = 321) and population control group (n = 332), long/long CA genotypes were significantly associated with disease risk (p = 0.042), and most strongly when one allele was a 24 CA repeat (p = 0.0023). In addition, longer CA allele length was associated with earlier age-of-onset (p = 0.039), and shorter survival duration in bulbar-onset cases (p = 0.006). In an Australian longitudinal sALS cohort (n = 67), ALS functional rating scale scores were significantly lower in carriers of the long/long genotype (p = 0.034). Stathmin-2 mRNA expression was reduced in sporadic patient ONS cells. Additionally, sALS patients and controls exhibited variable expression of Stathmin-2 mRNA according to CA genotype in laser-captured spinal motor neurons.

Conclusions

We report a novel non-coding CA repeat in Stathmin-2 which is associated with sALS disease risk and has disease modifying effects. The potential value of this variant as a disease marker and tool for cohort enrichment in clinical trials warrants further investigation.

Differential effects of sex on longitudinal patterns of cognitive decline in Parkinson's disease

Background

Cognitive impairment is an important and diverse symptom of Parkinson’s disease (PD). Sex is a purported risk variable for cognitive decline in PD, but has not been comprehensively investigated.

Objectives

This cross-sectional and longitudinal study examined sex differences in global and domain-specific cognitive performance in a large PD cohort.

Methods

Cognitive function was evaluated using the Addenbrooke’s Cognitive Examination in 392 people with PD (PwP) from the Australian Parkinson’s Disease Registry. The influence of sex on domain-specific cognitive performance was investigated using covariate-corrected generalised linear models. In a repeated measures longitudinal subset of 127 PwP, linear mixed models were used to assess the impact of sex on cognition over time, while accounting for covariates.

Results

Cross-sectional-corrected modelling revealed that sex was significantly predictive of cognitive performance, with males performing worse than females on global cognition, and memory and fluency domains. Longitudinally, sex was significantly predictive of cognitive decline, with males exhibiting a greater reduction in global cognition and language, whereas females showed a greater decline in attention/orientation, memory and visuospatial domains, despite starting with higher baseline scores. At follow-up, a significantly higher proportion of males than females fulfilled criteria for mild cognitive impairment or PD dementia.

Conclusions

Sex was revealed as a significant determinant of overall cognitive performance as well as specific cognitive domains, with a differential pattern of decline in male and female participants. Such sex-specific findings appear to explain some of the heterogeneity observed in PD, warranting further investigation of mechanisms underlying this sexual dimorphism.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-020-10367-8.

Vascular miR-181b controls tissue factor-dependent thrombogenicity and inflammation in type 2 diabetes

BACKGROUND

Diabetes mellitus is characterized by chronic vascular inflammation leading to pathological expression of the thrombogenic full length (fl) tissue factor (TF) and its isoform alternatively-spliced (as) TF. Blood-borne TF promotes factor (F) Xa generation resulting in a pro-thrombotic state and cardiovascular complications. MicroRNA (miR)s impact gene expression on the post-transcriptional level and contribute to vascular homeostasis. Their distinct role in the control of the diabetes-related procoagulant state remains poorly understood.

METHODS

In a cohort of patients with poorly controlled type 2 diabetes (n = 46) plasma levels of miR-181b were correlated with TF pathway activity and markers for vascular inflammation. In vitro, human microvascular endothelial cells (HMEC)-1 and human monocytes (THP-1) were transfected with miR-181b or anti-miR-181b and exposed to tumor necrosis factor (TNF) α or lipopolysaccharides (LPS). Expression of TF isoforms, vascular adhesion molecule (VCAM) 1 and nuclear factor (NF) κB nuclear translocation was assessed. Moreover, aortas, spleen, plasma, and bone marrow-derived macrophage (BMDM)s of mice carrying a deletion of the first miR-181b locus were analyzed with respect to TF expression and activity.

RESULTS

In patients with type 2 diabetes, plasma miR-181b negatively correlated with the procoagulant state as evidenced by TF protein, TF activity, D-dimer levels as well as markers for vascular inflammation. In HMEC-1, miR-181b abrogated TNFα-induced expression of flTF, asTF, and VCAM1. These results were validated using the anti-miR-181b. Mechanistically, we confirmed a miR-181b-mediated inhibition of importin-α3 (KPNA4) leading to reduced nuclear translocation of the TF transcription factor NFκB. In THP-1, miR-181b reduced both TF isoforms and FXa generation in response to LPS due to targeting phosphatase and tensin homolog (PTEN), a principal inducer for TF in monocytes. Moreover, in miR-181-/- animals, we found that reduced levels of miR-181b were accompanied by increased TF, VCAM1, and KPNA4 expression in aortic tissue as well as increased TF and PTEN expression in spleen. Finally, BMDMs of miR-181-/- mice showed increased TF expression and FXa generation upon stimulation with LPS.

CONCLUSIONS

miR-181b epigenetically controls the procoagulant state in diabetes. Reduced miR-181b levels contribute to increased thrombogenicity and may help to identify individuals at particular risk for thrombosis.

MicroRNA-181a regulates IFN-γ expression in effector CD8+ T cell differentiation

CD8⁺ T cells are key players in immunity against intracellular infections and tumors. The main cytokine associated with these protective responses is interferon-γ (IFN-γ), whose production is known to be regulated at the transcriptional level during CD8⁺ T cell differentiation. Here we found that microRNAs constitute a posttranscriptional brake to IFN-γ expression by CD8⁺ T cells, since the genetic interference with the Dicer processing machinery resulted in the overproduction of IFN-γ by both thymic and peripheral CD8⁺ T cells. Using a gene reporter mouse for IFN-γ locus activity, we compared the microRNA repertoires associated with the presence or absence of IFN-γ expression. This allowed us to identify a set of candidates, including miR-181a and miR-451, which were functionally tested in overexpression experiments using synthetic mimics in peripheral CD8⁺ T cell cultures. We found that miR-181a limits IFN-γ production by suppressing the expression of the transcription factor Id2, which in turn promotes the Ifng expression program. Importantly, upon MuHV-4 challenge, miR-181a-deficient mice showed a more vigorous IFN-γ⁺ CD8⁺ T cell response and were able to control viral infection significantly more efficiently than control mice. These data collectively establish a novel role for miR-181a in regulating IFN-γ–mediated effector CD8⁺ T cell responses in vitro and in vivo.

Development of Unconventional T Cells Controlled by MicroRNA

Post-transcriptional gene regulation through microRNA (miRNA) has emerged as a major control mechanism of multiple biological processes, including development and function of T cells. T cells are vital components of the immune system, with conventional T cells playing a central role in adaptive immunity and unconventional T cells having additional functions reminiscent of both innate and adaptive immunity, such as involvement in stress responses and tissue homeostasis. Unconventional T cells encompass cells expressing semi-invariant T cell receptors (TCRs), such as invariant Natural Killer T (iNKT) and Mucosal-Associated Invariant T (MAIT) cells. Additionally, some T cells with diverse TCR repertoires, including γδT cells, intraepithelial lymphocytes (IEL) and regulatory T (Treg) cells, share some functional and/or developmental features with their semi-invariant unconventional counterparts. Unconventional T cells are particularly sensitive to disruption of miRNA function, both globally and on the individual miRNA level. Here, we review the role of miRNA in the development and function of unconventional T cells from an iNKT-centric point of view. The function of single miRNAs can provide important insights into shared and individual pathways for the formation of different unconventional T cell subsets.

miR-181a/b-1 controls thymic selection of Treg cells and tunes their suppressive capacity

The interdependence of selective cues during development of regulatory T cells (Treg cells) in the thymus and their suppressive function remains incompletely understood. Here, we analyzed this interdependence by taking advantage of highly dynamic changes in expression of microRNA 181 family members miR-181a-1 and miR-181b-1 (miR-181a/b-1) during late T-cell development with very high levels of expression during thymocyte selection, followed by massive down-regulation in the periphery. Loss of miR-181a/b-1 resulted in inefficient de novo generation of Treg cells in the thymus but simultaneously permitted homeostatic expansion in the periphery in the absence of competition. Modulation of T-cell receptor (TCR) signal strength in vivo indicated that miR-181a/b-1 controlled Treg-cell formation via establishing adequate signaling thresholds. Unexpectedly, miR-181a/b-1-deficient Treg cells displayed elevated suppressive capacity in vivo, in line with elevated levels of cytotoxic T-lymphocyte-associated 4 (CTLA-4) protein, but not mRNA, in thymic and peripheral Treg cells. Therefore, we propose that intrathymic miR-181a/b-1 controls development of Treg cells and imposes a developmental legacy on their peripheral function.

miRNA miR-21 Is Largely Dispensable for Intrathymic T-Cell Development

Development of T cells in the thymus is tightly controlled to continually produce functional, but not autoreactive, T cells. miRNAs provide a layer of post-transcriptional gene regulation to this process, but the role of many individual miRNAs in T-cell development remains unclear. miR-21 is prominently expressed in immature thymocytes followed by a steep decline in more mature cells. We hypothesized that such a dynamic expression was indicative of a regulatory function in intrathymic T-cell development. To test this hypothesis, we analyzed T-cell development in miR-21-deficient mice at steady state and under competitive conditions in mixed bone-marrow chimeras. We complemented analysis of knock-out animals by employing over-expression in vivo. Finally, we assessed miR-21 function in negative selection in vivo as well as differentiation in co-cultures. Together, these experiments revealed that miR-21 is largely dispensable for physiologic T-cell development. Given that miR-21 has been implicated in regulation of cellular stress responses, we assessed a potential role of miR-21 in endogenous regeneration of the thymus after sublethal irradiation. Again, miR-21 was completely dispensable in this process. We concluded that, despite prominent and highly dynamic expression in thymocytes, miR-21 expression was not required for physiologic T-cell development or endogenous regeneration.

miR-191 modulates B-cell development and targets transcription factors E2A, Foxp1, and Egr1

The interdependence of posttranscriptional gene regulation via miRNA and transcriptional regulatory networks in lymphocyte development is poorly understood. Here, we identified miR-191 as direct upstream modulator of a transcriptional module comprising the transcription factors Foxp1, E2A, and Egr1. Deletion as well as ectopic expression of miR-191 resulted in developmental arrest in B lineage cells, indicating that fine tuning of the combined expression levels of Foxp1, E2A, and Egr1, which in turn control somatic recombination and cytokine-driven expansion, constitutes a prerequisite for efficient B-cell development. In conclusion, we propose that miR-191 acts as a rheostat in B-cell development by fine tuning a key transcriptional program.

Adaptor device for shortening guide catheters to access distal lesions in coronary angioplasty

One of the challenges in interventional cardiology is accessing distal stenoses in both native coronary arteries and bypass grafts. This article reports the fabrication and use of an adaptor device that can be connected to the proximal segment of a shortened guide catheter for easier and safer access to these distal lesions.

Calcium channel agonist/antagonist effects on cholinergic stimulation of the diabetic rat bladder

The in vitro effects of a calcium channel agonist (BAY K8644) and antagonist (nifedipine) on the cholinergic responses of the streptozotocin-induced diabetic rat bladder were investigated. the bladder body and bladder base were studied separately. There were significant differences in contractile responses to acetylcholine stimulation in the diabetic bladder body compared to the control body. Similarly, the diabetic bladder base demonstrated significantly increased contractile responses compared to the control base. Contractile responses in the diabetic bladder body and base were significantly increased from the control in the absence of extracellular calcium. Differences were found in the effects on maximum responses between diabetic and control tissues treated with nifedipine and BAY K8644. BAY K8644 did not completely reverse the effect of nifedipine on the contractile responses. Rates of contractile response were significantly different between controls and diabetics and between body and base. Alterations in calcium channel activity in diabetic bladder smooth muscle may be responsible at least in part for the nonspecific pharmacologic responses found in smooth muscle strips.

Neurogenic function of the diabetic rat bladder: alteration by calcium channel effectors

The in vitro effects of a calcium channel antagonist (nifedipine) and agonist (BAY K8644) on the neurogenic responses of the streptozotocin-induced diabetic rat bladder were investigated. The bladder body and bladder base were studied separately. There were no significant differences in neurogenic responses in diabetic bladder body compared to control body, but the diabetic bladder base demonstrated an increased contractile response at each frequency compared to control base. The rate of contractile response was similar in controls and diabetics but was significantly different between body and base. Although declining with time, contractile responses in the diabetic bladder body and base were increased from control in the absence of extracellular calcium. Differences were found in effects upon maximum responses between diabetic and control tissues treated with nifedipine and BAY K8644. BAY K8644 did not completely reverse the effect of nifedipine on the neurogenic responses in the diabetic bladder body. Effects of diabetes on the bladder body and base are associated with changes in calcium channel activity of bladder smooth muscle.