Improving Reproducibility of Phenotypic Assessments in the DyW Mouse Model of Laminin-α2 Related Congenital Muscular Dystrophy

Laminin-α2 related Congenital Muscular Dystrophy (LAMA2-CMD) is a progressive muscle disease caused by partial or complete deficiency of laminin-211, a skeletal muscle extracellular matrix protein. In the last decade, basic science research has queried underlying disease mechanisms in existing LAMA2-CMD murine models and identified possible clinical targets and pharmacological interventions. Experimental rigor in preclinical studies is critical to efficiently and accurately quantify both negative and positive results, degree of efficiency of potential therapeutics and determine whether to move a compound forward for additional preclinical testing. In this review, we compare published available data measured to assess three common parameters in the widely used mouse model DyW, that mimics LAMA2-CMD, we quantify variability and analyse its possible sources. Finally, on the basis of this analysis, we suggest standard set of assessments and the use of available standardized protocols, to reduce variability of outcomes in the future and to improve the value of preclinical research

Independent Regulation of Reovirus Membrane Penetration and Apoptosis by the μ1 ϕ Domain

Apoptosis plays an important role in the pathogenesis of reovirus encephalitis. Reovirus outer-capsid protein μ1, which functions to penetrate host cell membranes during viral entry, is the primary regulator of apoptosis following reovirus infection. Ectopic expression of full-length and truncated forms of μ1 indicates that the μ1 ϕ domain is sufficient to elicit a cell death response. To evaluate the contribution of the μ1 ϕ domain to the induction of apoptosis following reovirus infection, ϕ mutant viruses were generated by reverse genetics and analyzed for the capacity to penetrate cell membranes and elicit apoptosis. We found that mutations in ϕ diminish reovirus membrane penetration efficiency by preventing conformational changes that lead to generation of key reovirus entry intermediates. Independent of effects on membrane penetration, amino acid substitutions in ϕ affect the apoptotic potential of reovirus, suggesting that ϕ initiates apoptosis subsequent to cytosolic delivery. In comparison to wild-type virus, apoptosis-defective ϕ mutant viruses display diminished neurovirulence following intracranial inoculation of newborn mice. These results indicate that the ϕ domain of μ1 plays an important regulatory role in reovirus-induced apoptosis and disease

Corporate philanthropy through the lens of ethical subjectivity

The dynamic organisational processes in businesses dilute the boundaries between the individual, organisational, and societal drivers of corporate philanthropy. This creates a complex framework in which charitable project selection occurs. Using the example of European tour operators, this study investigates the mechanisms through which companies invest in charitable projects in overseas destinations. Inextricably linked to this is the increasing contestation by local communities as to how they are able to engage effectively with tourism in order to realise the benefits tourism development can bring. This research furthers such debates by exploring the processes through which tour operators facilitate community development through charitable giving. Findings show, with no formal frameworks in existence, project selection depends upon emergent strategies that connect the professional with the personal, with trust being positioned as a central driver of these informal processes. Discretionary responsibilities are reworked through business leaders’ commitment to responsible business practises and the ethical subjectivity guiding these processes

Genomic Relationships, Novel Loci, and Pleiotropic Mechanisms across Eight Psychiatric Disorders

Genetic influences on psychiatric disorders transcend diagnostic boundaries, suggesting substantial pleiotropy of contributing loci. However, the nature and mechanisms of these pleiotropic effects remain unclear. We performed analyses of 232,964 cases and 494,162 controls from genome-wide studies of anorexia nervosa, attention-deficit/hyper-activity disorder, autism spectrum disorder, bipolar disorder, major depression, obsessive-compulsive disorder, schizophrenia, and Tourette syndrome. Genetic correlation analyses revealed a meaningful structure within the eight disorders, identifying three groups of inter-related disorders. Meta-analysis across these eight disorders detected 109 loci associated with at least two psychiatric disorders, including 23 loci with pleiotropic effects on four or more disorders and 11 loci with antagonistic effects on multiple disorders. The pleiotropic loci are located within genes that show heightened expression in the brain throughout the lifespan, beginning prenatally in the second trimester, and play prominent roles in neurodevelopmental processes. These findings have important implications for psychiatric nosology, drug development, and risk prediction.Peer reviewe

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Increasing frailty is associated with higher prevalence and reduced recognition of delirium in older hospitalised inpatients: results of a multi-centre study

Purpose: Delirium is a neuropsychiatric disorder delineated by an acute change in cognition, attention, and consciousness. It is common, particularly in older adults, but poorly recognised. Frailty is the accumulation of deficits conferring an increased risk of adverse outcomes. We set out to determine how severity of frailty, as measured using the CFS, affected delirium rates, and recognition in hospitalised older people in the United Kingdom. Methods: Adults over 65 years were included in an observational multi-centre audit across UK hospitals, two prospective rounds, and one retrospective note review. Clinical Frailty Scale (CFS), delirium status, and 30-day outcomes were recorded. Results: The overall prevalence of delirium was 16.3% (483). Patients with delirium were more frail than patients without delirium (median CFS 6 vs 4). The risk of delirium was greater with increasing frailty [OR 2.9 (1.8–4.6) in CFS 4 vs 1–3; OR 12.4 (6.2–24.5) in CFS 8 vs 1–3]. Higher CFS was associated with reduced recognition of delirium (OR of 0.7 (0.3–1.9) in CFS 4 compared to 0.2 (0.1–0.7) in CFS 8). These risks were both independent of age and dementia. Conclusion: We have demonstrated an incremental increase in risk of delirium with increasing frailty. This has important clinical implications, suggesting that frailty may provide a more nuanced measure of vulnerability to delirium and poor outcomes. However, the most frail patients are least likely to have their delirium diagnosed and there is a significant lack of research into the underlying pathophysiology of both of these common geriatric syndromes

New Congenital Mouse Model to Study Laminin Protein Therapy for Muscular Dystrophy

Merosin deficient congenital muscular dystrophy type 1A (MDC1A) is caused by the loss of laminin-211 and laminin-221 heterotrimers which are most abundant in skeletal and cardiac muscle basal lamina; mutations in the LAMA2 gene cause the loss of these laminin isoforms. This absence of laminin-211/221 in MDC1A reduces the capacity for myofiber adhesion, loss of sarcolemmal integrity and subsequently the ability of the skeletal muscle syncytium to generate force in a coordinated and efficient manner. Patients experience progressive muscle wasting which confines them to a wheelchair at an early age and respiratory failure that leads to their untimely death. Currently, there is no effective treatment or cure for this devastating disease. Previous studies have shown that laminin-111, an embryonic form of laminin, delivered before disease onset can reduce muscle pathology and improve viability in the dyW-/- mouse model of MDC1A. These studies suggested that laminin-111 may act to strengthen and reinforce the sarcolemma and provide a protective niche for muscle repair. Since most patients are diagnosed with MDC1A after disease onset, we determined if laminin-111 could be beneficial after disease onset. Our studies suggest dyW-/- mice treated with laminin-111 after disease onset show improvement in muscle function and histology. Results from this study along with an understanding of laminin-111 pharmacokinetics will help pave the way in developing this protein as an exciting potential therapeutic for MDC1A patients. Duchenne Muscular Dystrophy (DMD) is the most common X-linked disease affecting 1 in 3,300 live male births. Patients with DMD suffer from severe, progressive muscle wasting and weakness with clinical symptoms first detected between 2 to 5 years of age; as the disease progresses patients are confined to a wheelchair in their teens and die in their early 20s mainly due to cardiopulmonary complications. DMD is caused by the loss of the sarcolemmal protein dystrophin (427kDa) due to mutations in the dystophin gene. When present, dystrophin acts as a scaffold linking the cell cytoskeleton to the extracellular matrix. This loss of dystrophin in DMD results in patients experiencing greater susceptibility to muscle damage via reduced structural and functional integrity of their muscle. One potential therapeutic avenue that needs to be explored involves increasing the levels of the ?7?1 integrin in order to compensate for the loss of dystrophin. To test this hypothesis, a muscle cell-based assay was developed in order to report ?7 integrin promoter activity with the intent of identifying molecules that promote ?7 integrin expression. Laminin-111 was identified as an enhancer of ?7 integrin expression. Theoretically, the identification of ?7 integrin enhancing compounds that help boost ?7?1 integrin expression as part of drug-based therapies may lead to a novel therapeutic approach for the treatment of this disease. Systemic laminin-111 treatment significantly reduces myofiber degeneration in both forms of MDC1A and DMD muscular dystrophy. This dissertation reinforces the potential of laminin-111 as a systemic protein therapy, capable of restoring sarcolemmal integrity thus reducing muscle disease progression. The importance of ?7 integrin in skeletal and cardiac muscle was highlighted here through the generation of the ?7-/-:: laminin-?2-/- double knockout mouse model. This mouse has never been studied before and could prove to be another important mouse model needed to explore therapeutic avenues for muscular dystrophy

A New Congenital Mouse Model to Study Laminin Protein Therapy for Muscular Dystrophy

Merosin deficient congenital muscular dystrophy type 1A (MDC1A) is caused by the loss of laminin-211 and laminin-221 heterotrimers which are most abundant in skeletal and cardiac muscle basal lamina; mutations in the LAMA2 gene cause the loss of these laminin isoforms. This absence of laminin-211/221 in MDC1A reduces the capacity for myofiber adhesion, loss of sarcolemmal integrity and subsequently the ability of the skeletal muscle syncytium to generate force in a coordinated and efficient manner. Patients experience progressive muscle wasting which confines them to a wheelchair at an early age and respiratory failure that leads to their untimely death. Currently, there is no effective treatment or cure for this devastating disease. Previous studies have shown that laminin-111, an embryonic form of laminin, delivered before disease onset can reduce muscle pathology and improve viability in the dyW-/- mouse model of MDC1A. These studies suggested that laminin-111 may act to strengthen and reinforce the sarcolemma and provide a protective niche for muscle repair. Since most patients are diagnosed with MDC1A after disease onset, we determined if laminin-111 could be beneficial after disease onset. Our studies suggest dyW-/- mice treated with laminin-111 after disease onset show improvement in muscle function and histology. Results from this study along with an understanding of laminin-111 pharmacokinetics will help pave the way in developing this protein as an exciting potential therapeutic for MDC1A patients. Duchenne Muscular Dystrophy (DMD) is the most common X-linked disease affecting 1 in 3,300 live male births. Patients with DMD suffer from severe, progressive muscle wasting and weakness with clinical symptoms first detected between 2 to 5 years of age; as the disease progresses patients are confined to a wheelchair in their teens and die in their early 20s mainly due to cardiopulmonary complications. DMD is caused by the loss of the sarcolemmal protein dystrophin (427kDa) due to mutations in the dystophin gene. When present, dystrophin acts as a scaffold linking the cell cytoskeleton to the extracellular matrix. This loss of dystrophin in DMD results in patients experiencing greater susceptibility to muscle damage via reduced structural and functional integrity of their muscle. One potential therapeutic avenue that needs to be explored involves increasing the levels of the α7β1 integrin in order to compensate for the loss of dystrophin. To test this hypothesis, a muscle cell-based assay was developed in order to report α7 integrin promoter activity with the intent of identifying molecules that promote α7 integrin expression. Laminin-111 was identified as an enhancer of α7 integrin expression. Theoretically, the identification of α7 integrin enhancing compounds that help boost α7β1 integrin expression as part of drug-based therapies may lead to a novel therapeutic approach for the treatment of this disease. Systemic laminin-111 treatment significantly reduces myofiber degeneration in both forms of MDC1A and DMD muscular dystrophy. This dissertation reinforces the potential of laminin-111 as a systemic protein therapy, capable of restoring sarcolemmal integrity thus reducing muscle disease progression. The importance of α7 integrin in skeletal and cardiac muscle was highlighted here through the generation of the α7-/-:: laminin-α2-/- double knockout mouse model. This mouse has never been studied before and could prove to be another important mouse model needed to explore therapeutic avenues for muscular dystrophy