Cerebral small vessel disease (cSVDs) account for 25% of stroke and are a frequent cause of cognitive or motor disability in adults. In a small number of patients, cSVDs result from monogenic diseases, the most frequent being cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). An early disease onset, a suggestive family history, and a low vascular risk profile contrasting with a high load of cSVD imaging markers represent red flags that must trigger molecular screening. To date, a dozen of genes is involved in Mendelian cSVDs, most of them are responsible for autosomal dominant conditions of variable penetrance. Some of these mendelian cSVDs (CADASIL, HTRA1-related cSVD, pontine autosomal dominant microangiopathy and leukoencephalopathy (PADMAL), cathepsin-A related arteriopathy with strokes and leukoencephalopathy (CARASAL), and cSVD related to LAMB1 mutations) are causing ischemic stroke. Others (COL4A1/COL4A2-related angiopathy and hereditary cerebral amyloid angiopathy) preferentially lead to intracerebral hemorrhages. The clinical features of different Mendelian cSVDs can overlap. Therefore, the current approach is based on simultaneous screening of all genes involved in these conditions through a panel-targeted sequencing gene or exome sequencing. Nevertheless, a pathogenic variant is identified in less than 15% of patients with a suspected genetic cerebrovascular disease, suggesting that many additional genes remain to be identified.

Cardiac conduction disorders predispose individuals to arrhythmias, currently but the exact mechanisms of cardiac conduction remain elusive. The study sought to identify the causal association between circulating plasma proteins and electrocardiogram (ECG) traits, offer valuable biological insights and clinical guidance into cardiac conduction. Proteome-wide Mendelian randomization (MR) analysis was firstly conducted to assess causal associations between plasma proteins and five ECG traits, including P wave duration (PWD), QRS duration, PR, QT and RR intervals. Multiple sensitivity analyses were implemented. The reverse MR analysis, colocalization analysis and replication analysis were used to consolidate the reliability of our results. Then, we conducted mediation analysis to explore potential mechanism between plasma proteins and ECG traits. The gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were applied to clarify the biological functions of target proteins. Finally, phenome-wide MR (Phe-MR) and drug databases were searched. We identified 3 proteins (FAM151A, VEGF165, VEGF121) associated with PWD, 12 proteins (ABHD10, ADK, Cathepsin_S, DUSP13, Ephrin_A3, MAPRE2, OMG, PAM, PMM1, SH3BGRL3, TCP4, SYT11) linked to PR interval, 1 protein (PKC_A) related to QRS duration, and 2 proteins (MXRA7, SVEP1) associated with QT interval. A significant causal effects of ECG traits on them was not found in reverse MR. Colocalization and replication analyses strengthened our findings further. The impacts were partly mediated by anthropometric measures. Enrichment analysis of target proteins mainly enriched for multiple key pathways such as regulation of hydrolase activity and fibronectin binding. Through drug databases searching, 5 identified proteins (VEGFA, ADK, PAM, Cathepsin_S, PKC_A) were considered druggable. We discovered significant causal associations between genetically predicted levels of 18 plasma proteins and ECG traits. These results highlight the importance of circulating plasma proteins in cardiac conduction and open up the possibility of novel arrhythmia drug development.

More than 2000 compounds have been reported from cyanobacteria. The most successful example is dolastatin 10, of which a related compound monomethylauristatin E is used as antibody-drug conjugate (ADC) for Hodgkin lymphoma and systemic anaplastic large cell lymphoma. Recently genome-based analyses by Piel led to the discovery of novel compounds from cyanobacteria. W. H. Gerwick found a potential as anti-SARS-CoV-2 agent in gallinamide A, which was reported as a cathepsin L inhibitor. In our group columbamides were isolated from the marine cyanobacterium Moorena bouillonii. The geometry of the double bond was determined by the coupling constant obtained using non-decoupled heteronuclear single quantum coherence (HSQC). The configuration of chloromethine in a long-chain acyl moiety was determined by the Ohrui method at room temperature using a chiral HPLC column. Columbamide D showed biosurfactant activity. One strain many compounds (OSMAC) is a method to discover new compounds by changing culture conditions. Prior to our experiments, attempts to apply OSMAC in cyanobacteria resulted in the induction or up-regulation of only known compounds. The heat shock culture of the freshwater cyanobacterium Microcystis aeruginosa up-regulated a ribosomal peptide argicyclamide C. At the same time, we discovered bis-prenylated and monoprenylated argicyclamides A and B. More recently iron-limited culture produced hydroxylated argicyclamide A. OSMAC and genome-based screening could lead the discovery of unique biologically active compounds from cyanobacteria.

Monogenic diseases, although rare, should be always considered in the diagnostic work up of vascular dementia (VaD), particularly in patients with early onset and a familial history of dementia or cerebrovascular disease. They include, other than CADASIL, Fabry disease, Col4A1-A2 related disorders, which are well recognized causes of VaD, other heritable diseases such as mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) and cathepsin-A related arteriopathy strokes and leukoencephalopathy (CARASAL). MELAS, caused by mtDNA (80% of adult cases m.3243A>G mutations) and more rarely POLG1 mutations, has minimum prevalence of 3.5/100,000. CARASAL, which is caused by mutations in the CTSA gene, has been described in about 19 patients so far. In both these two disorders cognitive features have not been fully explored and are described only in case series or families. This review paper is aimed at providing an update on the clinical manifestations, with particular focus on cognitive aspects, but also neuroradiological and genetic features of these less frequent monogenic diseases associated with VaD.

Cathepsin A-related arteriopathy with strokes and leukoencephalopathy (CARASAL) is a rare monogenic cause of cerebral small vessel disease. To date, fewer than 15 patients with CARASAL have been described, all of common European ancestry. Clinical and imaging phenotypes of two patients are presented. Genetic variants were identified using targeted Sanger and focused exome sequencing, respectively. Both patients carried the same pathogenic p.Arg325Cys mutation in CTSA. One patient of Chinese ethnicity presented with migraine, tinnitus and slowly progressive cognitive impairment with significant cerebral small vessel disease in the absence of typical cardiovascular risk factors. She later suffered an ischaemic stroke. A second patient from Brazil, of Italian ethnicity developed progressive dysphagia and dysarthria in his 50s, he later developed hearing loss and chronic disequilibrium. Magnetic resonance imaging in both cases demonstrated extensive signal change in the deep cerebral white matter, anterior temporal lobes, thalami, internal and external capsules and brainstem. CARASAL should be considered in patients with early onset or severe cerebral small vessel disease, particularly where there are prominent symptoms or signs related to brainstem involvement, such as hearing dysfunction, tinnitus or dysphagia or where there is significant thalamic and brainstem involvement on imaging.