Role of COL4A1 in small-vessel disease and hemorrhagic stroke

Characterization of Retinal Microvascular Abnormalities in Birdshot Chorioretinopathy Using OCT Angiography

Objective

To characterize changes in the retinal microvasculature in eyes with birdshot chorioretinopathy (BCR) using OCT angiography (OCTA).

Design

Retrospective, observational, single center.

Subjects

Twenty-eight patients (53 eyes) with BCR and 59 age-matched controls (110 eyes).

Methods

En face OCTA images of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) of each eye were assessed for the presence of microvascular abnormalities and used to measure the vessel and foveal avascular zone (FAZ) areas. A longitudinal analysis was performed with a representative cohort of 23 BCR eyes (16 patients) at baseline and at a 2-year time point.

Main Outcome Measures

Whole-image vessel density (VD, %), extrafoveal avascular zone (extra-FAZ) VD (%), and FAZ area (%) were calculated and compared between control and BCR eyes. The frequency of microvascular abnormalities in BCR eyes was recorded.

Results

In the SCP, increased intercapillary space and capillary loops were common features present on OCTA images. Whole-image and extra-FAZ VD were lower in the BCR group compared with controls (P < 0.0001 [SCP and DCP]). Foveal avascular zone area was enlarged in BCR eyes (P = 0.0008 [DCP]). Worsening best-corrected visual acuity was associated with a decrease in whole-image and extra-FAZ VD in the SCP (P < 0.0001 for both) and the DCP (P < 0.005 for both). Multivariable analysis, with vessel analysis parameters as outcomes, demonstrated that increasing age, increasing disease duration, lower central subfield thickness, and treatment-naive eyes (compared with those on only biologics) were associated with a significant decrease in both DCP whole-image and extra-FAZ VD. Increasing disease duration was associated with a significant decrease in both SCP whole-image and extra-FAZ VD. Longitudinal analysis demonstrated no significant difference in any vessel analysis parameters except for an increase in DCP FAZ area.

Conclusions

Our results demonstrate a significant a decrease in VD in BCR eyes and an association on multivariable analysis with disease duration. Quantifying VD in the retinal microvasculature may be a useful biomarker for monitoring disease severity and progression in patients with BCR. Further studies with extended longitudinal follow-up are needed to characterize its utility in monitoring disease progression and treatment response.

Financial Disclosures

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Good Outcome of Resective Epilepsy Surgery in a 1-Year-Old Child with Drug-Resistant Focal Epilepsy with a Novel Pathogenic COL4A1 Mutation

Pathogenic variants in COL4A1, encoding the α chain of type IV collagen, have been associated with cerebrovascular pathology as well as malformations of cortical development, thereby causing structural epilepsy. This case illustrates successful resective epilepsy surgery in a 12-month-old girl with left occipital focal cortical dysplasia (FCD) associated with a heterozygous splice-donor variant in COL4A1. She presented with drug-resistant focal epilepsy with daily seizures from the age of 2 months, refractory to several combinations of antiseizure medications, as well as mild right-sided hemiparesis and developmental delay. All presurgical diagnostic modalities, including ictal and interictal electroencephalography, magnetic resonance imaging, and ictal fluorodeoxyglucose positron emission tomography, showed congruent findings, pointing toward one single left occipital epileptogenic zone (EZ). We performed a left occipital lobectomy, using intraoperative electrocorticography to confirm the boundaries of the EZ. After surgery, the patient has remained seizure free, and both cognitive and motor developments have improved. Histopathology of the resected brain tissue showed FCD type Ia. Resective epilepsy surgery can have a very good outcome, also in patients with genetic mutations in COL4A1, constituting a less invasive option than the previously used more radical surgical procedures such as hemispherectomy.

Multiorgan manifestations of COL4A1 and COL4A2 variants and proposal for a clinical management protocol

COL4A1/2 variants are associated with highly variable multiorgan manifestations. Depicting the whole clinical spectrum of COL4A1/2-related manifestations is challenging, and there is no consensus on management and preventative strategies. Based on a systematic review of current evidence on COL4A1/2-related disease, we developed a clinical questionnaire that we administered to 43 individuals from 23 distinct families carrying pathogenic variants. In this cohort, we extended ophthalmological and cardiological examinations to asymptomatic individuals and those with only limited or mild, often nonspecific, clinical signs commonly occurring in the general population (i.e., oligosymptomatic). The most frequent clinical findings emerging from both the literature review and the questionnaire included stroke (203/685, 29.6%), seizures or epilepsy (199/685, 29.0%), intellectual disability or developmental delay (168/685, 24.5%), porencephaly/schizencephaly (168/685, 24.5%), motor impairment (162/685, 23.6%), cataract (124/685, 18.1%), hematuria (63/685, 9.2%), and retinal arterial tortuosity (58/685, 8.5%). In oligosymptomatic and asymptomatic carriers, ophthalmological investigations detected retinal vascular tortuosity (5/13, 38.5%), dysgenesis of the anterior segment (4/13, 30.8%), and cataract (2/13, 15.4%), while cardiological investigations were unremarkable except for mild ascending aortic ectasia in 1/8 (12.5%). Our multimodal approach confirms highly variable penetrance and expressivity in COL4A1/2-related conditions, even at the intrafamilial level with neurological involvement being the most frequent and severe finding in both children and adults. We propose a protocol for prevention and management based on individualized risk estimation and periodic multiorgan evaluations.

Gliovascular transcriptional perturbations in Alzheimer's disease reveal molecular mechanisms of blood brain barrier dysfunction

To uncover molecular changes underlying blood-brain-barrier dysfunction in Alzheimer's disease, we performed single nucleus RNA sequencing in 24 Alzheimer's disease and control brains and focused on vascular and astrocyte clusters as main cell types of blood-brain-barrier gliovascular-unit. The majority of the vascular transcriptional changes were in pericytes. Of the vascular molecular targets predicted to interact with astrocytic ligands, SMAD3, upregulated in Alzheimer's disease pericytes, has the highest number of ligands including VEGFA, downregulated in Alzheimer's disease astrocytes. We validated these findings with external datasets comprising 4,730 pericyte and 150,664 astrocyte nuclei. Blood SMAD3 levels are associated with Alzheimer's disease-related neuroimaging outcomes. We determined inverse relationships between pericytic SMAD3 and astrocytic VEGFA in human iPSC and zebrafish models. Here, we detect vast transcriptome changes in Alzheimer's disease at the gliovascular-unit, prioritize perturbed pericytic SMAD3-astrocytic VEGFA interactions, and validate these in cross-species models to provide a molecular mechanism of blood-brain-barrier disintegrity in Alzheimer's disease.

COL4A1 gene mutations and perinatal intracranial hemorrhage in neonates: case reports and literature review

Intracranial hemorrhage may represent a complication of the perinatal period that affects neonatal morbidity and mortality. Very poor data exist about a possible association between mutations of the type IV collagen a1 chain (COL4A1) gene and the development of intracranial hemorrhage, and only sporadic reports focus on intracerebral bleedings already developing in utero or in the neonatal period in infants with such a mutation. This study presents a case series of term neonates affected by intracranial hemorrhage, with no apparent risk factors for the development of this condition, who were carriers of COL4A1 gene variants. This study also provides a review of the most recent scientific literature on this topic, specifically focusing on the available scientific data dealing with the perinatal period.

Diffusion imaging genomics provides novel insight into early mechanisms of cerebral small vessel disease

Cerebral small vessel disease (cSVD) is a leading cause of stroke and dementia. Genetic risk loci for white matter hyperintensities (WMH), the most common MRI-marker of cSVD in older age, were recently shown to be significantly associated with white matter (WM) microstructure on diffusion tensor imaging (signal-based) in young adults. To provide new insights into these early changes in WM microstructure and their relation with cSVD, we sought to explore the genetic underpinnings of cutting-edge tissue-based diffusion imaging markers across the adult lifespan. We conducted a genome-wide association study of neurite orientation dispersion and density imaging (NODDI) markers in young adults (i-Share study: N = 1 758, (mean[range]) 22.1[18-35] years), with follow-up in young middle-aged (Rhineland Study: N = 714, 35.2[30-40] years) and late middle-aged to older individuals (UK Biobank: N = 33 224, 64.3[45-82] years). We identified 21 loci associated with NODDI markers across brain regions in young adults. The most robust association, replicated in both follow-up cohorts, was with Neurite Density Index (NDI) at chr5q14.3, a known WMH locus in VCAN. Two additional loci were replicated in UK Biobank, at chr17q21.2 with NDI, and chr19q13.12 with Orientation Dispersion Index (ODI). Transcriptome-wide association studies showed associations of STAT3 expression in arterial and adipose tissue (chr17q21.2) with NDI, and of several genes at chr19q13.12 with ODI. Genetic susceptibility to larger WMH volume, but not to vascular risk factors, was significantly associated with decreased NDI in young adults, especially in regions known to harbor WMH in older age. Individually, seven of 25 known WMH risk loci were associated with NDI in young adults. In conclusion, we identified multiple novel genetic risk loci associated with NODDI markers, particularly NDI, in early adulthood. These point to possible early-life mechanisms underlying cSVD and to processes involving remyelination, neurodevelopment and neurodegeneration, with a potential for novel approaches to prevention.

Pathophysiology of cerebral small vessel disease: a journey through recent discoveries

Cerebral small vessel disease (cSVD) encompasses a heterogeneous group of age-related small vessel pathologies that affect multiple regions. Disease manifestations range from lesions incidentally detected on neuroimaging (white matter hyperintensities, small deep infarcts, microbleeds, or enlarged perivascular spaces) to severe disability and cognitive impairment. cSVD accounts for approximately 25% of ischemic strokes and the vast majority of spontaneous intracerebral hemorrhage and is also the most important vascular contributor to dementia. Despite its high prevalence and potentially long therapeutic window, there are still no mechanism-based treatments. Here, we provide an overview of the recent advances in this field. We summarize recent data highlighting the remarkable continuum between monogenic and multifactorial cSVDs involving NOTCH3, HTRA1, and COL4A1/A2 genes. Taking a vessel-centric view, we discuss possible cause-and-effect relationships between risk factors, structural and functional vessel changes, and disease manifestations, underscoring some major knowledge gaps. Although endothelial dysfunction is rightly considered a central feature of cSVD, the contributions of smooth muscle cells, pericytes, and other perivascular cells warrant continued investigation.

Hepatotoxicity assessment of innovative nutritional supplements based on olive-oil formulations enriched with natural antioxidants

Introduction

This study focuses on the assessment of extra virgin olive-oil and olive fruit-based formulations enriched with natural antioxidants as potential nutritional supplements for alleviating symptoms and long-term consequences of illnesses whose molecular pathophysiology is affected by oxidative stress and inflammation, such as Alzheimer's disease (AD).

Methods

Besides evaluating cell viability and proliferation capacity of human hepatocellular carcinoma HepG2 cells exposed to formulations in culture, hepatotoxicity was also considered as an additional safety measure using quantitative real-time PCR on RNA samples isolated from the cell cultures and applying approaches of targeted molecular analysis to uncover potential pathway effects through gene expression profiling. Furthermore, the formulations investigated in this work contrast the addition of natural extract with chemical forms and evaluate the antioxidant delivery mode on cell toxicity.

Results

The results indicate minimal cellular toxicity and a significant beneficial impact on metabolic molecular pathways in HepG2 cell cultures, thus paving the way for innovative therapeutic strategies using olive-oil and antioxidants in dietary supplements to minimize the long-term effects of oxidative stress and inflammatory signals in individuals being suffered by disorders like AD.

Discussion

Overall, the experimental design and the data obtained support the notion of applying innovative molecular methodologies and research techniques to evidently advance the delivery, as well as the scientific impact and validation of nutritional supplements and dietary products to improve public health and healthcare outcomes.

The Dawn and Advancement of the Knowledge of the Genetics of Migraine

Background: Migraine is a prevalent episodic brain disorder known for recurrent attacks of unilateral headaches, accompanied by complaints of photophobia, phonophobia, nausea, and vomiting. Two main categories of migraine are migraine with aura (MA) and migraine without aura (MO). Main body: Early twin and population studies have shown a genetic basis for these disorders, and efforts have been invested since to discern the genes involved. Many techniques, including candidate-gene association studies, loci linkage studies, genome-wide association, and transcription studies, have been used for this goal. As a result, several genes were pinned with concurrent and conflicting data among studies. It is important to understand the evolution of techniques and their findings. Conclusions: This review provides a chronological understanding of the different techniques used from the dawn of migraine genetic investigations and the genes linked with the migraine subtypes.

Association of the COL4A2 Gene Polymorphisms with Primary Intracerebral Hemorrhage Risk and Outcome in Chinese Han Population

The relationship of single nucleotide polymorphisms (SNPs) in COL4A2 gene with risk and outcome of primary intracerebral hemorrhage (ICH) in the Chinese Han population remains unclear, which was investigated in this study. Primary ICH patients and non-stroke controls of Chinese Han ethnicity were enrolled. The genotypes of 8 tag-SNPs were determined using a custom-by-design 48-Plex SNPscan Kit. Poor 3-month outcome was defined as modified Rankin Scale score 4-6. Logistic regression was employed to examine association between COL4A2 variants and risk and poor outcome of primary ICH. 323 patients with primary ICH and 376 stroke-free controls were included. Compared to controls, the rs1049931 G and rs1049906 C alleles were associated with increased ICH risk (p = 0.027 and 0.033), and these two allele counts increased this risk after adjustments respectively (additive model: adjusted OR [aOR] 1.41, 95% CI 1.03-1.94, corrected p = 0.043; aOR 1.37, 95% CI 1.01-1.86, corrected p = 0.043). The rs1049931 AG/GG and rs1049906 CT/CC genotypes showed increased susceptibility to non-lobar hemorrhage (aOR 1.63, 95% CI 1.06-2.50, p = 0.025; aOR 1.63, 95% CI 1.07-2.47, p = 0.022). Haplotype analysis revealed an association between rs1049906-rs1049931 haplotype CG and ICH risk (OR 1.36, 95% CI 1.05-1.78, p = 0.021). Regarding clinical outcome, the rs3803230 C allele (dominant model: aOR 1.94, 95% CI 1.04-3.63, p = 0.037) and haplotype AC of rs7990214-rs3803230 (OR 1.98, 95% CI 1.13-3.46, p = 0.015) contributed to 3-month poor outcome. The COL4A2 polymorphisms are associated with an increased risk of primary ICH, mainly non-lobar hemorrhage, and with long-term poor outcome after ICH in Chinese Han population.

Repetitive head trauma and apoE4 induce chronic cerebrovascular alterations that impair tau elimination from the brain

Repetitive mild traumatic brain injuries (r-mTBI) sustained in the military or contact sports have been associated with the accumulation of extracellular tau in the brain, which may contribute to the pathogenesis of neurodegenerative tauopathies. The expression of the apolipoprotein E4 (apoE4) isoform has been associated with higher levels of tau in the brain, and worse clinical outcomes after r-mTBI, though the influence of apoE genotype on extracellular tau dynamics in the brain is poorly understood. We recently demonstrated that extracellular tau can be eliminated across blood-brain barrier (BBB), which is progressively impaired following r-mTBI. The current studies investigated the influence of repetitive mild TBI (r-mTBI) and apoE genotype on the elimination of extracellular solutes from the brain. Following intracortical injection of biotin-labeled tau into humanized apoE-Tr mice, the levels of exogenous tau residing in the brain of apoE4 mice were elevated compared to other isoforms, indicating reduced tau elimination. Additionally, we found exposure to r-mTBI increased tau residence in apoE2 mice, similar to our observations in E2FAD animals. Each of these findings may be the result of diminished tau efflux via LRP1 at the BBB, as LRP1 inhibition significantly reduced tau uptake in endothelial cells and decreased tau transit across an in vitro model of the BBB (basolateral-to-apical). Notably, we showed that injury and apoE status, (particularly apoE4) resulted in chronic alterations in BBB integrity, pericyte coverage, and AQP4 polarization. These aberrations coincided with an atypical reactive astrocytic gene signature indicative of diminished CSF-ISF exchange. Our work found that CSF movement was reduced in the chronic phase following r-mTBI (>18 months post injury) across all apoE genotypes. In summary, we show that apoE genotype strongly influences cerebrovascular homeostasis, which can lead to age-dependent deficiencies in the elimination of toxic proteins from the brain, like tau, particularly in the aftermath of head trauma.

Glycosylation Modulates the Structure and Functions of Collagen: A Review

Collagens are fundamental constituents of the extracellular matrix and are the most abundant proteins in mammals. Collagens belong to the family of fibrous or fiber-forming proteins that self-assemble into fibrils that define their mechanical properties and biological functions. Up to now, 28 members of the collagen superfamily have been recognized. Collagen biosynthesis occurs in the endoplasmic reticulum, where specific post-translational modification-glycosylation-is also carried out. The glycosylation of collagens is very specific and adds β-d-galactopyranose and β-d-Glcp-(1→2)-d-Galp disaccharide through β-O-linkage to hydroxylysine. Several glycosyltransferases, namely COLGALT1, COLGALT2, LH3, and PGGHG glucosidase, were associated the with glycosylation of collagens, and recently, the crystal structure of LH3 has been solved. Although not fully understood, it is clear that the glycosylation of collagens influences collagen secretion and the alignment of collagen fibrils. A growing body of evidence also associates the glycosylation of collagen with its functions and various human diseases. Recent progress in understanding collagen glycosylation allows for the exploitation of its therapeutic potential and the discovery of new agents. This review will discuss the relevant contributions to understanding the glycosylation of collagens. Then, glycosyltransferases involved in collagen glycosylation, their structure, and catalytic mechanism will be surveyed. Furthermore, the involvement of glycosylation in collagen functions and collagen glycosylation-related diseases will be discussed.

Infantile hemiparesis and porencephaly due to a COL4A1 mutation: Gould syndrome

Gould syndrome is an autosomal dominant syndrome due to a COL4A1 or COL4A2 mutation that is commonly characterised by familial porencephaly, seizures, intracranial haemorrhages, cataracts, nephropathies and more. There have been up to 137 identified patients based on a review of the literature. In this case, we describe a male infant that presents with hemiparesis, developmental delay and gait abnormalities at his well-child check. Referral to neurology and a subsequent MRI demonstrated porencephaly and ocular lens abnormalities. Genetic sequencing uncovered a mutation to the COL4A1 gene, suggesting Gould syndrome. There are no family members with similar phenotypes. Mutations to the COL4A1 and COL4A2 genes result in disruption of collagen found in most basement membranes, resulting in a variety of phenotypes that can make diagnosis difficult. Genetic identification of these patients is critical as these patients require a multidisciplinary approach to care and specific counselling on risk reduction techniques.

Identification of genomic characteristics and selective signals in Guizhou black goat

BACKGROUND

Guizhou black goat is one of the indigenous black goat breeds in the southwest region of Guizhou, China, which is an ordinary goat for mutton production. They are characterized by moderate body size, black coat, favorite meat quality with tender meat and lower odor, and tolerance for cold and crude feed. However, little is known about the genetic characteristics or variations underlying their important economic traits.

RESULTS

Here, we resequenced the whole genome of Guizhou black goat from 30 unrelated individuals breeding in the five core farms. A total of 9,835,610 SNPs were detected, and 2,178,818 SNPs were identified specifically in this breed. The population structure analysis revealed that Guizhou black goat shared a common ancestry with Shaanbei white cashmere goat (0.146), Yunshang black goat (0.103), Iran indigenous goat (0.054), and Moroccan goat (0.002). However, Guizhou black goat showed relatively higher genetic diversity and a lower level of linkage disequilibrium than the other seven goat breeds by the analysis of the nucleotide diversity, linkage disequilibrium decay, and runs of homozygosity. Based on FST and θπ values, we identified 645, 813, and 804 selected regions between Guizhou black goat and Yunshang black goat, Iran indigenous goat, and cashmere goats. Combined with the results of XP-EHH, there were 286, 322, and 359 candidate genes, respectively. Functional annotation analysis revealed that these genes are potentially responsible for the immune response (e.g., CD28, CD274, IL1A, TLR2, and SLC25A31), humility-cold resistance (e.g., HBEGF, SOSTDC1, ARNT, COL4A1/2, and EP300), meat quality traits (e.g., CHUK, GAB2, PLAAT3, and EP300), growth (e.g., GAB2, DPYD, and CSF1), fertility (e.g., METTL15 and MEI1), and visual function (e.g., PANK2 and NMNAT2) in Guizhou black goat.

CONCLUSION

Our results indicated that Guizhou black goat had a high level of genomic diversity and a low level of linkage disequilibrium in the whole genome. Selection signatures were detected in the genomic regions that were mainly related to growth and development, meat quality, reproduction, disease resistance, and humidity-cold resistance in Guizhou black goat. These results would provide a basis for further resource protection and breeding improvement of this very local breed.

Collagen type IV alpha 1 chain (COL4A1) expression in the developing human lung

BACKGROUND

Collagen type IV alpha 1 chain (COL4A1) in the basement membrane is an important component during lung development, as suggested from animal models where COL4A1 has been shown to regulate alveolarization and angiogenesis. Less is known about its role in human lung development. Our aim was to study COL4A1 expression in preterm infants with different lung maturational and clinical features.

METHODS

COL4A1 expression in 115 lung samples from newborn infants (21-41 weeks' gestational age; 0-228 days' postnatal age [PNA]) was studied by immunohistochemistry combined with digital image analysis. Cluster analysis was performed to find subgroups according to immunohistologic and clinical data.

RESULTS

Patients were automatically categorized into 4 Groups depending on their COL4A1 expression. Expression of COL4A1 was mainly extracellular in Group 1, low in Group 2, intracellular in Group 3, and both extra- and intracellular in Group 4. Intracellular/extracellular ratio of COL4A1 expression related to PNA showed a distinctive postnatal maturational pattern on days 1-7, where intracellular expression of COL4A1 was overrepresented in extremely preterm infants.

CONCLUSIONS

COL4A1 expression seems to be highly dynamic during the postnatal life due to a possible rapid remodeling of the basement membrane. Intracellular accumulation of COL4A1 in the lungs of extremely premature infants occurs more frequently between 1 and 7 postnatal days than during the first 24 hours. In view of the lung arrest described in extremely preterm infants, the pathological and/or developmental role of postnatally increased intracellular COL4A1 as marker for basement membrane turnover, needs to be further investigated.

An mTurq2-Col4a1 mouse model allows for live visualization of mammalian basement membrane development

Basement membranes (BMs) are specialized sheets of extracellular matrix that underlie epithelial and endothelial tissues. BMs regulate the traffic of cells and molecules between compartments, and participate in signaling, cell migration, and organogenesis. The dynamics of mammalian BMs, however, are poorly understood, largely due to a lack of models in which core BM components are endogenously labeled. Here, we describe the mTurquoise2-Col4a1 mouse in which we fluorescently tag collagen IV, the main component of BMs. Using an innovative planar-sagittal live imaging technique to visualize the BM of developing skin, we directly observe BM deformation during hair follicle budding and basal progenitor cell divisions. The BM's inherent pliability enables dividing cells to remain attached to and deform the BM, rather than lose adhesion as generally thought. Using FRAP, we show BM collagen IV is extremely stable, even during periods of rapid epidermal growth. These findings demonstrate the utility of the mTurq2-Col4a1 mouse to shed new light on mammalian BM developmental dynamics.

Clinical and neuroimaging review of monogenic cerebral small vessel disease from the prenatal to adolescent developmental stage

Cerebral small vessel disease (cSVD) refers to a group of pathological processes with various etiologies affecting the small vessels of the brain. Most cases are sporadic, with age-related and hypertension-related sSVD and cerebral amyloid angiopathy being the most prevalent forms. Monogenic cSVD accounts for up to 5% of causes of stroke. Several causative genes have been identified. Sporadic cSVD has been widely studied whereas monogenic cSVD is still poorly characterized and understood. The majority of cases of both the sporadic and monogenic types, including cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), typically have their onset in adulthood. Types of cSVD with infantile and childhood onset are rare, and their diagnosis is often challenging. The present review discusses the clinical and neuroimaging findings of monogenic cSVD from the prenatal to adolescent period of development. Early diagnosis is crucial to enabling timely interventions and family counseling.

Exploring miRNA-target gene pair detection in disease with coRmiT

A wide range of approaches can be used to detect micro RNA (miRNA)-target gene pairs (mTPs) from expression data, differing in the ways the gene and miRNA expression profiles are calculated, combined and correlated. However, there is no clear consensus on which is the best approach across all datasets. Here, we have implemented multiple strategies and applied them to three distinct rare disease datasets that comprise smallRNA-Seq and RNA-Seq data obtained from the same samples, obtaining mTPs related to the disease pathology. All datasets were preprocessed using a standardized, freely available computational workflow, DEG_workflow. This workflow includes coRmiT, a method to compare multiple strategies for mTP detection. We used it to investigate the overlap of the detected mTPs with predicted and validated mTPs from 11 different databases. Results show that there is no clear best strategy for mTP detection applicable to all situations. We therefore propose the integration of the results of the different strategies by selecting the one with the highest odds ratio for each miRNA, as the optimal way to integrate the results. We applied this selection-integration method to the datasets and showed it to be robust to changes in the predicted and validated mTP databases. Our findings have important implications for miRNA analysis. coRmiT is implemented as part of the ExpHunterSuite Bioconductor package available from https://bioconductor.org/packages/ExpHunterSuite.

Genomic analysis of presumed perinatal stroke in Saudi Arabia reveals a strong monogenic contribution

Perinatal stroke is associated with significant short- and long-term morbidity and has been recognized as the most common cause of cerebral palsy in term infants. The diagnosis of presumed perinatal stroke (PPS) is made in children who present with neurological deficit and/or seizures attributable to focal chronic infarction on neuroimaging and have uneventful neonatal history. The underlying mechanism of presumed perinatal stroke remains unknown and thorough investigation of potential monogenic causes has not been conducted to date. Here, we describe the use of untargeted exome sequencing to investigate a cohort of eight patients from six families with PPS. A likely deleterious variant was identified in four families. These include the well-established risk genes COL4A2 and JAM3. In addition, we report the first independent confirmation of the recently described link between ESAM and perinatal stroke. Our data also highlight NID1 as a candidate gene for the condition. This study suggests that monogenic disorders are important contributors to the pathogenesis of PPS and should be investigated by untargeted sequencing especially when traditional risk factors are excluded.

Late-Onset COL4A1 Mutation with Recurrent Ischemic and Hemorrhagic Strokes

INTRODUCTION

Mutations in type IV collagen gene COL4A1 are identified as a cause of autosomal dominant cerebrovascular disease. We report an unusual late-onset presentation.

CASE REPORT

A 64-year-old male was found to have an ischemic stroke and diffuse white matter changes. Genetic testing revealed COL4A1 gene mutation of heterozygous Alu insertion at intron 16. Alu elements are known as "jumping genes," and Alu insertion is not previously reported in COL4A1 genetic syndromes. Our case has attributes consistent with a heritable leukoencephalopathy: (1) late-onset presentation, (2) intracerebral hemorrhages and microbleeds, (3) bilateral symmetrical leukoencephalopathy, (4) recurrence over a short period of time, (5) bilateral retinopathy, and (6) family history notable for brain aneurysm, kidney diseases, and early-onset stroke.

CONCLUSIONS

Although the majority of COL4A1 genetic syndromes featuring cerebral small vessel disease are in children, this case highlights a late-onset patient with key features of COL4A1 syndromes associated with a heterozygous Alu intronic insertion.

Rare neurovascular genetic and imaging markers across neurodegenerative diseases

INTRODUCTION

Cerebral small vessel disease (SVD) is common in patients with cognitive impairment and neurodegenerative diseases such as Alzheimer's and Parkinson's. This study investigated the burden of magnetic resonance imaging (MRI)-based markers of SVD in patients with neurodegenerative diseases as a function of rare genetic variant carrier status.

METHODS

The Ontario Neurodegenerative Disease Research Initiative study included 520 participants, recruited from 14 tertiary care centers, diagnosed with various neurodegenerative diseases and determined the carrier status of rare non-synonymous variants in five genes (ABCC6, COL4A1/COL4A2, NOTCH3/HTRA1).

RESULTS

NOTCH3/HTRA1 were found to significantly influence SVD neuroimaging outcomes; however, the mechanisms by which these variants contribute to disease progression or worsen clinical correlates are not yet understood.

DISCUSSION

Further studies are needed to develop genetic and imaging neurovascular markers to enhance our understanding of their potential contribution to neurodegenerative diseases.

Impaired intracellular Ca2+ signaling contributes to age-related cerebral small vessel disease in Col4a1 mutant mice

Humans and mice with mutations in COL4A1 and COL4A2 manifest hallmarks of cerebral small vessel disease (cSVD). Mice with a missense mutation in Col4a1 at amino acid 1344 (Col4a1+/G1344D) exhibit age-dependent intracerebral hemorrhages (ICHs) and brain lesions. Here, we report that this pathology was associated with the loss of myogenic vasoconstriction, an intrinsic vascular response essential for the autoregulation of cerebral blood flow. Electrophysiological analyses showed that the loss of myogenic constriction resulted from blunted pressure-induced smooth muscle cell (SMC) membrane depolarization. Furthermore, we found that dysregulation of membrane potential was associated with impaired Ca2+-dependent activation of large-conductance Ca2+-activated K+ (BK) and transient receptor potential melastatin 4 (TRPM4) cation channels linked to disruptions in sarcoplasmic reticulum (SR) Ca2+ signaling. Col4a1 mutations impair protein folding, which can cause SR stress. Treating Col4a1+/G1344D mice with 4-phenylbutyrate, a compound that promotes the trafficking of misfolded proteins and alleviates SR stress, restored SR Ca2+ signaling, maintained BK and TRPM4 channel activity, prevented loss of myogenic tone, and reduced ICHs. We conclude that alterations in SR Ca2+ handling that impair ion channel activity result in dysregulation of SMC membrane potential and loss of myogenic tone and contribute to age-related cSVD in Col4a1+/G1344D mice.

Genetically proxied HTRA1 protease activity and circulating levels independently predict risk of ischemic stroke and coronary artery disease

HTRA1 has emerged as a major risk gene for stroke and cerebral small vessel disease with both rare and common variants contributing to disease risk. However, the precise mechanisms mediating this risk remain largely unknown as does the full spectrum of phenotypes associated with genetic variation in HTRA1 in the general population. Using a family-history informed approach, we first show that rare variants in HTRA1 are linked to ischemic stroke in 425,338 European individuals from the UK Biobank with replication in 143,149 individuals from the Biobank Japan. Integrating data from biochemical experiments on 76 mutations occurring in the UK Biobank, we next show that rare variants causing loss of protease function in vitro associate with ischemic stroke, coronary artery disease, and skeletal traits. In addition, a common causal variant (rs2672592) modulating circulating HTRA1 mRNA and protein levels enhances the risk of ischemic stroke, small vessel stroke, and coronary artery disease while lowering the risk of migraine and age-related macular dystrophy in GWAS and UK Biobank data from > 2,000,000 individuals. There was no evidence of an interaction between genetically proxied HTRA1 activity and levels. Our findings demonstrate a central role of HTRA1 for human disease including stroke and coronary artery disease and identify two independent mechanisms that might qualify as targets for future therapeutic interventions.

Postnatal Maturation of the Blood-Brain Barrier in Senescence-Accelerated OXYS Rats, Which Are Prone to an Alzheimer's Disease-like Pathology

Alzheimer's disease (AD) is an old-age neurodegenerative disorder; however, AD predisposition may arise early in life. Vascular dysfunction makes a big contribution to AD development. Nonetheless, the possible role of early-life vascular dysfunction in AD development is still poorly investigated. Here, using OXYS rats as a suitable model of the most common (sporadic) type of AD, we investigated maturation of the blood-brain barrier (BBB) in the hippocampus and frontal cortex in the first 3 weeks of life. Using RNA-Seq data, we found an altered expression of BBB-associated genes in the middle of the first and second weeks of life in OXYS rats compared to control rats (Wistar strain). Moreover, by immunohistochemistry and electronic microscopy, we revealed a delay of vascularization and of subsequent pericyte coating of blood vessels in OXYS rats. These specific features were accompanied by an accelerated decrease in BBB permeability estimated using Evans blue dye. Notably, almost all of the observed differences from Wistar rats disappeared on postnatal day 20. Nonetheless, the observed features, which are characteristic of the postnatal period, may have long-term consequences and contribute to neurovascular dysfunction observed in OXYS rats late in life, thereby promoting early development of AD signs.

Cortistatin deficiency reveals a dysfunctional brain endothelium with impaired gene pathways, exacerbated immune activation, and disrupted barrier integrity

BACKGROUND

Brain activity governing cognition and behaviour depends on the fine-tuned microenvironment provided by a tightly controlled blood-brain barrier (BBB). Brain endothelium dysfunction is a hallmark of BBB breakdown in most neurodegenerative/neuroinflammatory disorders. Therefore, the identification of new endogenous molecules involved in endothelial cell disruption is essential to better understand BBB dynamics. Cortistatin is a neuroimmune mediator with anti-inflammatory and neuroprotective properties that exerts beneficial effects on the peripheral endothelium. However, its role in the healthy and injured brain endothelium remains to be evaluated. Herein, this study aimed to investigate the potential function of endogenous and therapeutic cortistatin in regulating brain endothelium dysfunction in a neuroinflammatory/neurodegenerative environment.

METHODS

Wild-type and cortistatin-deficient murine brain endothelium and human cells were used for an in vitro barrier model, where a simulated ischemia-like environment was mimicked. Endothelial permeability, junction integrity, and immune response in the presence and absence of cortistatin were evaluated using different size tracers, immunofluorescence labelling, qPCR, and ELISA. Cortistatin molecular mechanisms underlying brain endothelium dynamics were assessed by RNA-sequencing analysis. Cortistatin role in BBB leakage was evaluated in adult mice injected with LPS.

RESULTS

The endogenous lack of cortistatin predisposes endothelium weakening with increased permeability, tight-junctions breakdown, and dysregulated immune activity. We demonstrated that both damaged and uninjured brain endothelial cells isolated from cortistatin-deficient mice, present a dysregulated and/or deactivated genetic programming. These pathways, related to basic physiology but also crucial for the repair after damage (e.g., extracellular matrix remodelling, angiogenesis, response to oxygen, signalling, and metabolites transport), are dysfunctional and make brain endothelial barrier lacking cortistatin non-responsive to any further injury. Treatment with cortistatin reversed in vitro hyperpermeability, tight-junctions disruption, inflammatory response, and reduced in vivo BBB leakage.

CONCLUSIONS

The neuropeptide cortistatin has a key role in the physiology of the cerebral microvasculature and its presence is crucial to develop a canonical balanced response to damage. The reparative effects of cortistatin in the brain endothelium were accompanied by the modulation of the immune function and the rescue of barrier integrity. Cortistatin-based therapies could emerge as a novel pleiotropic strategy to ameliorate neuroinflammatory/neurodegenerative disorders with disrupted BBB.

A Window into Mammalian Basement Membrane Development: Insights from the mTurq2-Col4a1 Mouse Model

Basement membranes (BMs) are specialized sheets of extracellular matrix that underlie epithelial and endothelial tissues. BMs regulate traffic of cells and molecules between compartments, and participate in signaling, cell migration and organogenesis. The dynamics of mammalian BMs, however, are poorly understood, largely due to a lack of models in which core BM components are endogenously labelled. Here, we describe the mTurquoise2-Col4a1 mouse, in which we fluorescently tag collagen IV, the main component of BMs. Using an innovative Planar-Sagittal live imaging technique to visualize the BM of developing skin, we directly observe BM deformation during hair follicle budding and basal progenitor cell divisions. The BM's inherent pliability enables dividing cells to remain attached to and deform the BM, rather than lose adhesion as generally thought. Using FRAP, we show BM collagen IV is extremely stable, even during periods of rapid epidermal growth. These findings demonstrate the utility of the mTurq2-Col4a1 mouse to shed new light on mammalian BM developmental dynamics.

Proteomic alterations in the brain and blood-brain barrier during brain Aβ accumulation in an APP knock-in mouse model of Alzheimer's disease

BACKGROUND

Blood-brain barrier (BBB) dysfunction is supposed to be an early event in the development of Alzheimer's disease (AD). This study aimed to investigate the relationship between BBB alterations and AD progression in terms of amyloid-β peptide (Aβ) accumulation in the brains of humanized amyloid precursor protein knock-in (APP-KI) mice.

METHODS

Brain Aβ accumulation was examined using immunohistochemical analysis. Alterations in differentially expressed proteins were determined using sequential window acquisition of all theoretical fragment ion mass spectroscopy (SWATH-MS)-based quantitative proteomics, and Metascape, STRING, Gene Ontology, and KEGG were used for network analyses of altered biological pathways and processes. Statistical significance was determined using the unpaired two-tailed Student's t-test and Welch's t-test for two groups and one-way analysis of variance followed by Tukey's test for more than two groups. Correlations between two groups were determined using Pearson's correlation analysis.

RESULTS

Brain Aβ accumulation in APP-KI mice was detectable at 2 months, increased significantly at 5 months, and remained elevated at 12 months of age. The levels of differentially expressed proteins in isolated brain capillaries were higher in younger mice, whereas those in the brain were higher in older mice. Network analyses indicated changes in basement membrane-associated and ribosomal proteins in the brain capillaries. There were no significant changes in key proteins involved in drug or Aβ transport at the BBB. In contrast, solute carrier transporter levels in astrocytes, microglia, and neurons were altered in the brain of older mice. Moreover, the levels of the lipid transporters Apoe and Apoj were upregulated in both the brain and isolated brain capillaries after Aβ accumulation.

CONCLUSIONS

Our results suggest that changes in the brain occurred after advanced Aβ accumulation, whereas initial Aβ accumulation was sufficient to cause alterations in the BBB. These findings may help elucidate the role of BBB alterations in AD progression and predict the distribution of drugs across the BBB in the brain of patients with AD.

Genotypic Analysis of COL4A1 Gene in Diabetic Nephropathy and Type 2 Diabetes Mellitus Patients: A Comparative Genetic Study

Diabetic nephropathy (DN) is specified by microalbuminuria, glomerular lesions, and renal fibrosis leading to end-stage renal disease. The pathophysiology of DN is multifactorial as a result of gene-environment interaction. Clinical studies suggested that gene mutations affect various pathways involved in DN, including extracellular matrix (ECM). During chronic hyperglycemia, collagen type-4-mediated ECM overproduction occurs, leading to renal fibrosis and DN development. In this study, COL4A1 gene variant rs605143 (G/A) was analyzed in diabetes and DN patients from the study population. We genotyped 386 study subjects, comprising 120 type 2 diabetes mellitus (T2DM) patients, 120 DN, and 146 healthy controls. All study subjects were analyzed for biochemical assays by commercially available kits and genotypic analysis by polymerase chain reaction-restriction fragment length polymorphism and confirmed by Sanger sequencing. Statistical analyses were done using SPSS and GraphPad. Anthroclinicopathological parameters showed a significant association between T2DM and DN. Genotype AA of COL4A1 gene variant rs605143 (G/A) showed a significant association with T2DM and DN compared with controls with 5.87- and 8.01-folds risk, respectively. Mutant allele A also significantly associated with T2DM and DN independently compared with healthy controls with 2.29- and 2.81-time risk in the study population. This study's findings suggested that COL4A1 gene variant rs605143 (G/A) can be used as predictive biomarkers for T2DM and DN independently. However, this gene variant needs to be analyzed in a large sample to explore the shared genetic association between T2DM and DN.

Correlation between neutrophil gelatinase phase lipocalin and cerebral small vessel disease

Background

Cerebral small vessel disease (CSVD) is common in the elderly population. Neutrophil gelatinase-associated lipocalin (NGAL) is closely related to cardiovascular and cerebrovascular diseases. NGAL causes pathological changes, such as damage to the vascular endothelium, by causing inflammation, which results in other related diseases. The purpose of this study was to investigate whether serum NGAL levels could predict disease severity in patients with CSVD.

Methods

The patients with CSVD who visited the Department of Neurology at the First Affiliated Hospital of Zhengzhou University between January 2018 and June 2022 were prospectively included. The total CSVD burden score was calculated using whole-brain magnetic resonance imaging (MRI), and the patients were divided into a mild group (total CSVD burden score < 2 points) and a severe group (total CSVD burden score ≥ 2 points). Age, sex, height, smoking and alcohol consumption history, medical history, and serological results of patients were collected to perform the univariate analysis. Multivariate logistic regression was used to analyze the risk factors that affect CSVD severity. The multiple linear regression method was used to analyze which individual CSVD markers (periventricular white matter hyperintensities, deep white matter hyperintensities, lacune, and cerebral microbleed) play a role in the association between total CSVD burden score and NGAL.

Results

A total of 427 patients with CSVD (140 in the mild group and 287 in the severe group) were included in the study. A multivariate logistic regression analysis showed that the following factors were significantly associated with CSVD severity: male sex [odds ratio(OR), 1.912; 95% confidence interval (CI), 1.150-3.179], age (OR, 1.046; 95% CI, 1.022-1.070), history of cerebrovascular disease (OR, 3.050; 95% CI, 1.764-5.274), serum NGAL level (OR, 1.005; 95% CI, 1.002-1.008), and diabetes (OR, 2.593; 95% CI, 1.424-4.722). A multivariate linear regression shows that periventricular white matter hyperintensities and cerebral microbleed are associated with serum NGAL concentrations (P < 0.05).

Conclusion

Serum NGAL level is closely related to CSVD severity and is a risk factor for the burden of CSVD brain damage. Serum NGAL has high specificity in reflecting the severity of CSVD.

Pathophysiology and probable etiology of cerebral small vessel disease in vascular dementia and Alzheimer's disease

Vascular cognitive impairment and dementia (VCID) is commonly caused by vascular injuries in cerebral large and small vessels and is a key driver of age-related cognitive decline. Severe VCID includes post-stroke dementia, subcortical ischemic vascular dementia, multi-infarct dementia, and mixed dementia. While VCID is acknowledged as the second most common form of dementia after Alzheimer's disease (AD) accounting for 20% of dementia cases, VCID and AD frequently coexist. In VCID, cerebral small vessel disease (cSVD) often affects arterioles, capillaries, and venules, where arteriolosclerosis and cerebral amyloid angiopathy (CAA) are major pathologies. White matter hyperintensities, recent small subcortical infarcts, lacunes of presumed vascular origin, enlarged perivascular space, microbleeds, and brain atrophy are neuroimaging hallmarks of cSVD. The current primary approach to cSVD treatment is to control vascular risk factors such as hypertension, dyslipidemia, diabetes, and smoking. However, causal therapeutic strategies have not been established partly due to the heterogeneous pathogenesis of cSVD. In this review, we summarize the pathophysiology of cSVD and discuss the probable etiological pathways by focusing on hypoperfusion/hypoxia, blood-brain barriers (BBB) dysregulation, brain fluid drainage disturbances, and vascular inflammation to define potential diagnostic and therapeutic targets for cSVD.

Axenfeld-Rieger syndrome: A systematic review examining genetic, neurological, and neurovascular associations to inform screening

Axenfeld-Rieger Syndrome (ARS) is comprised of a group of autosomal dominant disorders that are each characterized by anterior segment abnormalities of the eye. Mutations in the transcription factors FOXC1 or PITX2 are the most well-studied genetic manifestations of this syndrome. Due to the rarity this syndrome, ARS-associated neurological manifestations have not been well characterized. The purpose of this systematic review is to characterize and describe ARS neurologic manifestations that affect the cerebral vasculature and their early and late sequelae. PRISMA guidelines were followed; studies meeting inclusion criteria were analyzed for study design, evidence level, number of patients, patient age, whether the patients were related, genotype, ocular findings, and nervous system findings, specifically neurostructural and neurovascular manifestations. 63 studies met inclusion criteria, 60 (95%) were case studies or case series. The FOXC1 gene was most commonly found, followed by COL4A1, then PITX2. The most commonly described structural neurological findings were white matter abnormalities in 26 (41.3%) of studies, followed by Dandy-Walker Complex 12 (19%), and agenesis of the corpus callosum 11 (17%). Neurovascular findings were examined in 6 (9%) of studies, identifying stroke, cerebral small vessel disease (CSVD), tortuosity/dolichoectasia of arteries, among others, with no mention of moyamoya. This is the first systematic review investigating the genetic, neurological, and neurovascular associations with ARS. Structural neurological manifestations were common, yet often benign, perhaps limiting the utility of MRI screening. Neurovascular abnormalities, specifically stroke and CSVD, were identified in this population. Stroke risk was present in the presence and absence of cardiac comorbidities. These findings suggest a relationship between ARS and neurovascular findings; however, larger scale studies are necessary inform therapeutic decisions.

Endothelial depletion of Atg7 triggers astrocyte-microvascular disassociation at blood-brain barrier

Microvascular basement membrane (BM) plays a pivotal role in the interactions of astrocyte with endothelium to maintain the blood-brain barrier (BBB) homeostasis; however, the significance and precise regulation of the endothelial cell-derived BM component in the BBB remain incompletely understood. Here, we report that conditional knockout of Atg7 in endothelial cells (Atg7-ECKO) leads to astrocyte-microvascular disassociation in the brain. Our results reveal astrocytic endfeet detachment from microvessels and BBB leakage in Atg7-ECKO mice. Furthermore, we find that the absence of endothelial Atg7 downregulates the expression of fibronectin, a major BM component of the BBB, causing significantly reduced coverage of astrocytes along cerebral microvessels. We reveal Atg7 triggers the expression of endothelial fibronectin via regulating PKA activity to affect the phosphorylation of cAMP-responsive element-binding protein. These results suggest that Atg7-regulated endothelial fibronectin production is required for astrocytes adhesion to microvascular wall for maintaining the BBB homeostasis. Thus, endothelial Atg7 plays an essential role in astrocyte-endothelium interactions to maintain the BBB integrity.

LRP1 in vascular mural cells modulates cerebrovascular integrity and function in the presence of APOE4

Cerebrovasculature is critical in maintaining brain homeostasis; its dysregulation often leads to vascular cognitive impairment and dementia (VCID) during aging. VCID is the second most prevalent cause of dementia in the elderly, after Alzheimer's disease (AD), with frequent cooccurrence of VCID and AD. While multiple factors are involved in the pathogenesis of AD and VCID, APOE4 increases the risk for both diseases. A major apolipoprotein E (apoE) receptor, the low-density lipoprotein receptor-related protein 1 (LRP1), is abundantly expressed in vascular mural cells (pericytes and smooth muscle cells). Here, we investigated how deficiency of vascular mural cell LRP1 affects the cerebrovascular system and cognitive performance using vascular mural cell-specific Lrp1-KO mice (smLrp1-/-) in a human APOE3 or APOE4 background. We found that spatial memory was impaired in the 13- to 16-month-old APOE4 smLrp1-/- mice but not in the APOE3 smLrp1-/- mice, compared with their respective littermate control mice. These disruptions in the APOE4 smLrp1-/- mice were accompanied with excess paravascular glial activation and reduced cerebrovascular collagen IV. In addition, blood-brain barrier (BBB) integrity was disrupted in the APOE4 smLrp1-/- mice. Together, our results suggest that vascular mural cell LRP1 modulates cerebrovasculature integrity and function in an APOE genotype-dependent manner.

Extracellular matrix proteins in construction and function of in vitro blood-brain barrier models

The blood-brain barrier (BBB) is a highly impermeable barrier separating circulating blood and brain tissue. A functional BBB is critical for brain health, and BBB dysfunction has been linked to the pathophysiology of diseases such as stroke and Alzheimer’s disease. A variety of models have been developed to study the formation and maintenance of the BBB, ranging from in vivo animal models to in vitro models consisting of primary cells or cells differentiated from human pluripotent stem cells (hPSCs). These models must consider the composition and source of the cellular components of the neurovascular unit (NVU), including brain microvascular endothelial cells (BMECs), brain pericytes, astrocytes, and neurons, and how these cell types interact. In addition, the non-cellular components of the BBB microenvironment, such as the brain vascular basement membrane (BM) that is in direct contact with the NVU, also play key roles in BBB function. Here, we review how extracellular matrix (ECM) proteins in the brain vascular BM affect the BBB, with a particular focus on studies using hPSC-derived in vitro BBB models, and discuss how future studies are needed to advance our understanding of how the ECM affects BBB models to improve model performance and expand our knowledge on the formation and maintenance of the BBB.

Retinal Findings in Haemorrhagic Destruction of the Brain, Subependymal Calcification, and Congenital Cataracts (HDBSCC): Case Report and Review

We describe a child from a consanguineous family born with a rare autosomal recessive disorder affecting junctional adhesion molecule 3 (JAM3) causing profound neurological and ophthalmological injury known as haemorrhagic brain destruction, subependymal calcifications, and congenital cataracts (HDBSCC; MIM# 613730). She was the product of an unremarkable pregnancy and was born near to term but was noted shortly after birth to have congenital cataracts, poor vision, increased muscle tone, seizures, and developmental delay. Her older sister had an identical syndrome and had previously been documented to have homozygous mutations in JAM3. Examination in our patient, although difficult because of bilateral central cataracts, revealed very poor vision, attenuated retinal vessels, optic atrophy, and a retinal haemorrhage in the right eye, implying that abnormal development of the retinas and/or optic nerves may at times play a significant role in the poor vision noted in children with HDBSCC.

Massive MCA stroke requiring alteplase followed by thrombectomy in a 34-year-old female with alport syndrome

34-year-old-female with a medical history significant for Alport's syndrome, chronic kidney disease on dialysis, and hypertension, was brought to the emergency department for sudden onset aphasia and facial droop that began 30 min prior to arrival. She denied a history of prior strokes, recent illness, or fever. The vital signs on arrival as follows: blood pressure 151/71 mmHg, temperature of 98.4F, pulse of 77 beats/min, and respirations of 16 breaths/min. Upon examination, she appeared in mild distress with a left sided facial droop, right sided hemiparesis, and expressive aphasia, only answering to yes/no. Neurological examination revealed: expressive aphasia, intact sensation throughout the face and bilateral extremities, no effort in the right arm against gravity, some effort against gravity of the right leg, left arm and left leg had muscle strength of 5/5. Patient had an NIH stroke scale of 8. The remainder of the exam was unremarkable. Radiographic imaging with CT revealed no intracranial hemorrhage (Fig. 1) and the patient was given alteplase (tPA) injection 5.6 mg within 1 h of her arrival to the Emergency Department. After administration of tPA a CT perfusion scan was performed (Fig. 2). Imaging demonstrated decreased cerebral blood flow and prolonged mean transit time within the majority of the left middle cerebral artery territory, sparing the basal ganglia. This indicated a left middle cerebral artery M1 occlusion. Neurosurgery was consulted and the patient underwent thrombectomy. Her hospital course was complicated by hemorrhagic transformation (HT) on hospital day 2. The patient underwent MRI that showed a large left MCA distribution acute infarction with focal reperfusion hemorrhage and parenchymal hematoma measuring approximately 3 cm in each dimension (Fig. 3). This finding prompted emergent decompression and hemicraniectomy on day 2 of hospitalization. The patient was discharged on hospital day 17 to a rehab center.

Genetics of migraine: Delineation of contemporary understanding of the genetic underpinning of migraine

Migraine is a disabling episodic brain disorder with an increased familial relative risk, an increased concordance in monozygotic twins, and an estimated heritability of approximately 50%. Various genetic approaches have been applied to identify genetic factors conferring migraine risk. Initially, candidate gene associations studies (CGAS) have been performed that test DNA variants in genes prioritized based on presumed a priori knowledge of migraine pathophysiology. More recently, genome-wide association studies (GWAS) are applied that test genetic variants, single-nucleotide polymorphisms (SNPs), in a hypothesis-free manner. To date, GWAS have identified ~40 genetic loci associated with migraine. New GWAS data, which are expected to come out soon, will reveal over 100 loci. Also, large-scale GWAS, which have appeared for many traits over the last decade, have enabled studying the overlap in genetic architecture between migraine and its comorbid disorders. Importantly, other genetic factors that cannot be identified by a GWAS approach also confer risk for migraine. First steps have been taken to determine the contribution of these mechanisms by investigating mitochondrial DNA and epigenetic mechanisms. In addition to typical epigenetic mechanisms, that is, DNA methylation and histone modifications, also RNA-based mechanisms regulating gene silencing and activation have recently gotten attention. Regardless, until now, most relevant genetic discoveries related to migraine still come from investigating monogenetic syndromes with migraine as a prominent part of the phenotype. Experimental studies on these syndromes have expanded our knowledge on the mechanisms underlying migraine pathophysiology. It can be envisaged that when all (epi)genetic and phenotypic data on the common and rare forms of migraine will be integrated, this will help to unravel the biological mechanisms for migraine, which will likely guide decision-making in clinical practice in the future.

Elevated TGFβ signaling contributes to cerebral small vessel disease in mouse models of Gould syndrome

Cerebral small vessel disease (CSVD) is a leading cause of stroke and vascular cognitive impairment and dementia. Studying monogenic CSVD can reveal pathways that are dysregulated in common sporadic forms of the disease and may represent therapeutic targets. Mutations in collagen type IV alpha 1 (COL4A1) and alpha 2 (COL4A2) cause highly penetrant CSVD as part of a multisystem disorder referred to as Gould syndrome. COL4A1 and COL4A2 form heterotrimers [a1α1α2(IV)] that are fundamental constituents of basement membranes. However, their functions are poorly understood and the mechanism(s) by which COL4A1 and COL4A2 mutations cause CSVD are unknown. We used histological, molecular, genetic, pharmacological, and in vivo imaging approaches to characterize central nervous system (CNS) vascular pathologies in Col4a1 mutant mouse models of monogenic CSVD to provide insight into underlying pathogenic mechanisms. We describe developmental CNS angiogenesis abnormalities characterized by impaired retinal vascular outgrowth and patterning, increased numbers of mural cells with abnormal morphologies, altered contractile protein expression in vascular smooth muscle cells (VSMCs) and age-related loss of arteriolar VSMCs in Col4a1 mutant mice. Importantly, we identified elevated TGFβ signaling as a pathogenic consequence of Col4a1 mutations and show that genetically suppressing TGFβ signaling ameliorated CNS vascular pathologies, including partial rescue of retinal vascular patterning defects, prevention of VSMC loss, and significant reduction of intracerebral hemorrhages in Col4a1 mutant mice aged up to 8 months. This study identifies a novel biological role for collagen α1α1α2(IV) as a regulator of TGFβ signaling and demonstrates that elevated TGFβ signaling contributes to CNS vascular pathologies caused by Col4a1 mutations. Our findings suggest that pharmacologically suppressing TGFβ signaling could reduce the severity of CSVD, and potentially other manifestations associated with Gould syndrome and have important translational implications that could extend to idiopathic forms of CSVD.

Hypoxia-induced upregulation of matrix metalloproteinase 9 increases basement membrane degradation by downregulating collagen type IV alpha 1 chain

Hypoxia can cause basement membrane (BM) degradation in tissues. Matrix metalloproteinase 9 (MMP-9) is involved in various human cancers as well as BM degradation by downregulating type IV collagen (COL4). This study investigated the role of MMP-9 in hypoxia-mediated BM degradation in rat bone marrow based on its regulation of collagen type IV alpha 1 chain (COL4A1). Eighty male rats were randomly divided into four groups based on exposure to hypoxic conditions at a simulated altitude of 7,000 m, control (normoxia) and 3, 7, and 10 days of hypoxia exposure. BM degradation in bone marrow was determined by transmission electron microscopy. MMP-9 levels were assessed by western blot and real-time PCR, and COL4A1 levels were assessed by western blot and immunohistochemistry. Microvessels BMs in bone marrow exposed to acute hypoxia were observed by electron microscopy. MMP-9 expression increased, COL4A1 protein expression decreased, and BM degradation occurred in the 10-, 7-, and 3-day hypoxia groups compared with that in the control group (all P < 0.05). Hypoxia increased MMP-9 levels, which in turn downregulated COL4A1, thereby increasing BM degradation. MMP-9 upregulation significantly promoted BM degradation and COL4A1 downregulation. Our results suggest that MMP-9 is related to acute hypoxia-induced BM degradation in bone marrow by regulating COL4A1.

The Genetic Landscape of Ischemic Stroke in Children - Current Knowledge and Future Perspectives

Stroke in childhood has multiple etiologies, which are mostly distinct from those in adults. Genetic discoveries over the last decade pointed to monogenic disorders as a rare but significant cause of ischemic stroke in children and young adults, including small vessel and arterial ischemic stroke. These discoveries contributed to the understanding that stroke in children may be a sign of an underlying genetic disease. The identification of these diseases requires a detailed medical and family history collection, a careful clinical evaluation for the detection of systemic symptoms and signs, and neuroimaging assessment. Establishing an accurate etiological diagnosis and understanding the genetic risk factors for stroke are essential steps to decipher the underlying mechanisms, optimize the design of tailored prevention strategies, and facilitate the identification of novel therapeutic targets in some cases. Despite the increasing recognition of monogenic causes of stroke, genetic disorders remain understudied and therefore under-recognized in children with stroke. Increased awareness among healthcare providers is essential to facilitate accurate diagnosis in a timely manner. In this review, we provide a summary of the main single-gene disorders which may present as ischemic stroke in childhood and describe their clinical manifestations. We provide a set of practical suggestions for the diagnostic work up of these uncommon causes of stroke, based upon the stroke subtype and imaging characteristics that may suggest a monogenic diagnosis of ischemic stroke in children. Current hurdles in the genetic analyses of children with ischemic stroke as well as future prospectives are discussed.

Lysyl hydroxylase 3-mediated post-translational modifications are required for proper biosynthesis of collagen α1α1α2(IV)

Collagens are the most abundant proteins in the body and among the most biosynthetically complex. A molecular ensemble of over 20 endoplasmic reticulum resident proteins participates in collagen biosynthesis and contributes to heterogeneous post-translational modifications. Pathogenic variants in genes encoding collagens cause connective tissue disorders, including osteogenesis imperfecta, Ehlers-Danlos syndrome, and Gould syndrome (caused by mutations in COL4A1 and COL4A2), and pathogenic variants in genes encoding proteins required for collagen biosynthesis can cause similar but overlapping clinical phenotypes. Notably, pathogenic variants in lysyl hydroxylase 3 (LH3) cause a multisystem connective tissue disorder that exhibits pathophysiological features of collagen-related disorders. LH3 is a multifunctional collagen-modifying enzyme; however, its precise role(s) and substrate specificity during collagen biosynthesis has not been defined. To address this critical gap in knowledge, we generated LH3 KO cells and performed detailed quantitative and molecular analyses of collagen substrates. We found that LH3 deficiency severely impaired secretion of collagen α1α1α2(IV) but not collagens α1α1α2(I) or α1α1α1(III). Amino acid analysis revealed that LH3 is a selective LH for collagen α1α1α2(IV) but a general glucosyltransferase for collagens α1α1α2(IV), α1α1α2(I), and α1α1α1(III). Importantly, we identified rare variants that are predicted to be pathogenic in the gene encoding LH3 in two of 113 fetuses with intracranial hemorrhage-a cardinal feature of Gould syndrome. Collectively, our findings highlight a critical role of LH3 in α1α1α2(IV) biosynthesis and suggest that LH3 pathogenic variants might contribute to Gould syndrome.

A Neonatal Patient Diagnosed with a COL4A1 Mutation Presenting with Hemorrhagic Infarction and Severe Jaundice

We report a patient diagnosed with a COL4A1 mutation in the early postnatal period. Patients with early postnatal jaundice, intracranial lesions that are negative for TORCH syndrome, and recurrent hemolytic anemia should be suspected of having a COL4A1/COL4A2 gene mutation.

A Study on the Pathogenesis of Vascular Cognitive Impairment and Dementia: The Chronic Cerebral Hypoperfusion Hypothesis

The pathogenic mechanisms underlying vascular cognitive impairment and dementia (VCID) remain controversial due to the heterogeneity of vascular causes and complexity of disease neuropathology. However, one common feature shared among all these vascular causes is cerebral blood flow (CBF) dysregulation, and chronic cerebral hypoperfusion (CCH) is the universal consequence of CBF dysregulation, which subsequently results in an insufficient blood supply to the brain, ultimately contributing to VCID. The purpose of this comprehensive review is to emphasize the important contributions of CCH to VCID and illustrate the current findings about the mechanisms involved in CCH-induced VCID pathological changes. Specifically, evidence is mainly provided to support the molecular mechanisms, including Aβ accumulation, inflammation, oxidative stress, blood-brain barrier (BBB) disruption, trophic uncoupling and white matter lesions (WMLs). Notably, there are close interactions among these multiple mechanisms, and further research is necessary to elucidate the hitherto unsolved questions regarding these interactions. An enhanced understanding of the pathological features in preclinical models could provide a theoretical basis, ultimately achieving the shift from treatment to prevention.

Intracerebral Hemorrhage Genetics

Intracerebral hemorrhage (ICH) is a devastating type of stroke, frequently resulting in unfavorable functional outcomes. Up to 15% of stroke patients experience ICH and approximately half of those have a lethal outcome within a year. Considering the huge burden of ICH, timely prevention and optimized treatment strategies are particularly relevant. Nevertheless, ICH management options are quite limited, despite thorough research. More and more trials highlight the importance of the genetic component in the pathogenesis of ICH. Apart from distinct monogenic disorders of familial character, mostly occurring in younger subjects, there are numerous polygenic risk factors, such as hypertension, neurovascular inflammation, disorders of lipid metabolism and coagulation cascade, and small vessel disease. In this paper we describe gene-related ICH types and underlying mechanisms. We also briefly discuss the emerging treatment options and possible clinical relevance of the genetic findings in ICH management. Although existing data seems of more theoretical and scientific value so far, a growing body of evidence, combined with rapidly evolving experimental research, will probably serve clinicians in the future.

Whole-exome sequencing identified five novel de novo variants in patients with unexplained intellectual disability

Background

Intellectual disability (ID) represents a neurodevelopmental disorder, which is characterized by marked defects in the intellectual function and adaptive behavior, with an onset during the developmental period. ID is mainly caused by genetic factors, and it is extremely genetically heterogeneous. This study aims to identify the genetic cause of ID using trio‐WES analysis.

Methods

We recruited four pediatric patients with unexplained ID from non‐consanguineous families, who presented at the Department of Pediatrics, Guizhou Provincial People's Hospital. Whole‐exome sequencing (WES) and Sanger sequencing validation were performed in the patients and their unaffected parents. Furthermore, conservative analysis and protein structural and functional prediction were performed on the identified pathogenic variants.

Results

We identified five novel de novo mutations from four known ID‐causing genes in the four included patients, namely COL4A1 (c.2786T>A, p.V929D and c.2797G>A, p.G933S), TBR1 (c.1639_1640insCCCGCAGTCC, p.Y553Sfs*124), CHD7 (c.7013A>T, p.Q2338L), and TUBA1A (c.1350del, p.E450Dfs*34). These mutations were all predicted to be deleterious and were located at highly conserved domains that might affect the structure and function of these proteins.

Conclusion

Our findings contribute to expanding the mutational spectrum of ID‐related genes and help to deepen the understanding of the genetic causes and heterogeneity of ID.

Prenatal Diagnosis of COL4A1 Mutations in Eight Cases: Further Delineation of the Neurohistopathological Phenotype

BACKGROUND

Increasing number of mutations responsible for vascular lesions, leading to ischemic or hemorrhagic stroke in young adults, has been identified in the recent years. It has been demonstrated in both mice and humans, that mutations in COL4A1 gene promote cerebral hemorrhages. In humans, both adults and children may be affected, and the spectrum has been broadened recently to neonates and fetuses.

METHODS

We present a cohort of eight COL4A1 mutated fetuses in which cerebral hemorrhages were detected by ultrasound leading to elective terminations of pregnancy.

RESULTS

Our neuropathological studies demonstrated a strikingly similar pathological pattern, dominated by supra- and infratentorial multifocal hemorrhagic lesions of various abundance and age in the vicinity of enlarged small vessels having a discontinuous wall. This was constantly associated with a spectrum of supratentorial post-ischemic damages of the grey and white matters. Morphometric studies of brain vessels confirmed vascular dilation and hypervascularization in both grey and white matters and severe attenuation of the smooth-muscle actin staining in the white matter.

CONCLUSION

These observations add to the rare human neuropathological phenotype of COL4A1 mutations. Its recognition is mandatory to enhance the number of tested patients in the future, as well as the genetic counseling of parents.

Rare and Common Variants in COL4A1 in Chinese Patients With Intracerebral Hemorrhage

Here, we screened the COL4A1 variants in Chinese intracerebral hemorrhage (ICH) patients to summarize the relationship between the variants and clinical characteristics. Targeted sequencing of a 65-gene panel including COL4A1 was performed to detect all the coding regions and ±10-bp splicing sites. In total, 568 patients were included. Regarding rare nonsynonymous variants with a minor allele frequency (MAF) <0.5%, 6 missense variants and five suspicious splice site variants, absent in 573 healthy controls, were found in 11 patients. The subgroup carrying rare variants did not show specific phenotype compared with non-variant carriers. For the single nucleotide polymorphism (SNP) loci with an MAF> 5%, we did not find a significant association between the allele or genotype distribution of the SNP loci and the risk of ICH. Rs3742207 was nominally associated with death at 1-year follow-up (p = 0.02027, OR 1.857, 95% CI 1.101-3.133) after adjusted by age, hypertension history, hematoma volume and recurrent ICH history. Nevertheless, after the Bonferroni correction, the association was no longer significant. In conclusion, rare nonsynonymous variants in COL4A1 were identified in 1.94% (11/568) of Chinese ICH patients, while rs3742207 maybe indicate a worse prognosis of ICH.

Genetics of Spontaneous Intracerebral Hemorrhage: Risk and Outcome

Spontaneous intracerebral hemorrhage (ICH) is a common fatal event without an effective therapy. Of note, some familial aggregation and inherited tendency is found in ICH and heritability estimates indicate that genetic variations contribute substantially to ICH risk and outcome. Thus, identification of genetic variants that affect the occurrence and outcome may be helpful for ICH prevention and therapy. There are several reviews summarizing numerous genetic variants associated with the occurrence of ICH before, but genetic variants contributing to location distribution and outcome have rarely been introduced. Here, we summarize the current knowledge of genetic variants and pay special attention to location distribution and outcome. So far, investigations have reveled variations in APOE, GPX1, CR1, ITGAV, PRKCH, and 12q21.1 are associated with lobar ICH (LICH), while ACE, COL4A2, 1q22, TIMP1, TIMP2, MMP2, MMP9, and TNF are associated with deep ICH (DICH). Moreover, variations in APOE, VWF, 17p12, HP, CFH, IL6ST, and COL4A1 are possible genetic contributors to ICH outcome. Furthermore, the prospects for ICH related genetic studies from the bench to the bed were discussed.

Stroke Genetics: Discovery, Insight Into Mechanisms, and Clinical Perspectives

Stroke is the second leading cause of death worldwide and a complex, heterogeneous condition. In this review, we provide an overview of the current knowledge on monogenic and multifactorial forms of stroke, highlighting recent insight into the continuum between these. We describe how, in recent years, large-scale genome-wide association studies have enabled major progress in deciphering the genetic basis for stroke and its subtypes, although more research is needed to interpret these findings. We cover the potential of stroke genetics to reveal novel pathophysiological processes underlying stroke, to accelerate the discovery of new therapeutic approaches, and to identify individuals in the population who are at high risk of stroke and could be targeted for tailored preventative interventions.