Using VHH-Fc conjugates increases the blood half-life of the protein. However, purely extending the time window for brain uptake does not increase BBB passage. Nevertheless, VHH-Fc holds promise for therapeutic applications where a sustained systemic circulation of VHH is advantageous.

Background: Dysferlin mutations cause progressive muscular dystrophies with strong inflammation, yet its function in immune cells is unclear.Results: Dysferlin forms a protein complex with focal adhesion proteins, and its loss in monocytes results in deregulated adhesion. Conclusion: Dysferlin is involved in regulating cellular interactions in human monocytes. Significance: Dysferlin dysfunction in monocytes may contribute to pathology in dysferlinopathy.

Hereditary cerebral hemorrhage with amyloidosis‐Dutch type (HCHWA‐D) is an early onset hereditary form of cerebral amyloid angiopathy (CAA) pathology, caused by the E22Q mutation in the amyloid β (Aβ) peptide. Transforming growth factor β1 (TGFβ1) is a key player in vascular fibrosis and in the formation of angiopathic vessels in transgenic mice. Therefore, we investigated whether the TGFβ pathway is involved in HCHWA‐D pathogenesis in human postmortem brain tissue from frontal and occipital lobes. Components of the TGFβ pathway were analyzed with quantitative RT‐PCR. TGFβ1 and TGFβ Receptor 2 (TGFBR2) gene expression levels were significantly increased in HCHWA‐D in comparison to the controls, in both frontal and occipital lobes. TGFβ‐induced pro‐fibrotic target genes were also upregulated. We further assessed pathway activation by detecting phospho‐SMAD2/3 (pSMAD2/3), a direct TGFβ down‐stream signaling mediator, using immunohistochemistry. We found abnormal pSMAD2/3 granular deposits specifically on HCHWA‐D angiopathic frontal and occipital vessels. We graded pSMAD2/3 accumulation in angiopathic vessels and found a positive correlation with the CAA load independent of the brain area. We also observed pSMAD2/3 granules in a halo surrounding occipital vessels, which was specific for HCHWA‐D. The result of this study indicates an upregulation of TGFβ1 in HCHWA‐D, as was found previously in AD with CAA pathology. We discuss the possible origins and implications of the TGFβ pathway deregulation in the microvasculature in HCHWA‐D. These findings identify the TGFβ pathway as a potential biomarker of disease progression and a possible target of therapeutic intervention in HCHWA‐D.

AHNAK is a 700-kDa protein involved in cytoarchitecture and calcium signaling. It is secondarily reduced in muscle of dysferlinopathy patients and accumulates in muscle of calpainopathy patients, both affected by a muscular dystrophy. AHNAK directly interacts with dysferlin. This interaction is lost on cleavage of AHNAK by the protease calpain 3, explaining the molecular observations in patients. Currently, little is known of AHNAK regulation. We describe the self-regulation of multiple mRNA transcripts emanating from the AHNAK locus in muscle cells. We show that the AHNAK gene consists of a 17-kb exon flanked by multiple small exons. This genetic structure is shared by AHNAK2 and Periaxin, which share a common ancestor. Two major AHNAK transcripts are differentially expressed during muscle differentiation that encode for a small (17-kDa) and a large (700-kDa) protein isoform. These proteins interact in the cytoplasm, but the small AHNAK is also present in the nucleus. During muscle differentiation the small AHNAK is strongly increased, thereby establishing a positive feedback loop to regulate mRNA splicing of its own locus. A small 17-kDa isoform of Periaxin similarly traffics between the cytoplasm and the nucleus to regulate mRNA splicing. Thus, AHNAK constitutes a novel mechanism in post-transcriptional control of gene expression.

Background and Purpose— Previous studies of symptomatic and asymptomatic hereditary cerebral amyloid angiopathy (CAA) patients offered the possibility to study the radiological manifestations of CAA in the early stages of the disease. Recently, a striped cortex, observable as hypointense lines perpendicular to the pial surface on T 2 * -weighted 7T magnetic resonance imaging (MRI), was detected in 40% of the symptomatic hereditary CAA patients. However, the origin of these MRI contrast changes is unknown. This study aimed at defining the underlying pathology associated with the in vivo observed striped pattern. Methods— Formalin-fixed postmortem brain material including the occipital lobe of 4 hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D) cases and 6 sporadic CAA cases were selected from local neuropathology tissue collections. Depending on the availability of the material, intact hemispheres or brain slabs including the occipital lobe of these patients were screened for the presence of a striped cortex. Regions containing the striped cortex were then subjected to high-resolution 7T MRI and histopathologic examination. Results— We found 2 hereditary cerebral hemorrhage with amyloidosis-Dutch type cases and 1 sporadic CAA case with striped patterns in the occipital cortex resembling the in vivo signal. Histopathologic examination showed that the striped pattern in the cortex at 7T MRI is because of iron accumulation and calcification of penetrating arteries. The presence of both nonheme iron and calcification on penetrating arteries causes signal loss and hence the abnormal striped patterns in the cortical ribbon on T 2 * -weighted MRI. Conclusions— We identified iron accumulation and calcification of the vessel wall in hereditary cerebral hemorrhage with amyloidosis-Dutch type as the histopathologic correlates of the striped cortex observed on in vivo 7T MRI.

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Hereditary cerebral hemorrhage with amyloidosis-Dutch type (HCHWA-D) is an early onset hereditary form of cerebral amyloid angiopathy (CAA) caused by a point mutation resulting in an amino acid change (NP_000475.1:p.Glu693Gln) in the amyloid precursor protein (APP). Post-mortem frontal and occipital cortical brain tissue from nine patients and nine age-related controls was used for RNA sequencing to identify biological pathways affected in HCHWA-D. Although previous studies indicated that pathology is more severe in the occipital lobe in HCHWA-D compared to the frontal lobe, the current study showed similar changes in gene expression in frontal and occipital cortex and the two brain regions were pooled for further analysis. Significantly altered pathways were analyzed using gene set enrichment analysis (GSEA) on 2036 significantly differentially expressed genes. Main pathways over-represented by down-regulated genes were related to cellular aerobic respiration (including ATP synthesis and carbon metabolism) indicating a mitochondrial dysfunction. Principal up-regulated pathways were extracellular matrix (ECM)–receptor interaction and ECM proteoglycans in relation with an increase in the transforming growth factor beta (TGFβ) signaling pathway. Comparison with the publicly available dataset from pre-symptomatic APP-E693Q transgenic mice identified overlap for the ECM–receptor interaction pathway, indicating that ECM modification is an early disease specific pathomechanism.

Muon spin rotation is employed to investigate the spin dynamics of ferritin proteins isolated from the brain of an Alzheimer's disease (AD) patient and of a healthy control, using a sample of horse-spleen ferritin as a reference. A model based on the Néel theory of superparamagnetism is developed in order to interpret the spin relaxation rate of the muons stopped by the core of the protein. Using this model, our preliminary observations show that ferritins from the healthy control are filled with a mineral compatible with ferrihydrite, while ferritins from the AD patient contain a crystalline phase with a larger magnetocrystalline anisotropy, possibly compatible with magnetite or maghemite.