👤 Jillene Kogan

The transient, heterogeneous nano-bio interface defined by the protein corona in biological environments dictates the biodistribution, immune recognition, metabolism, and clearance of nanomaterials. Far from being a drawback, this corona can be harnessed for targeted nanodrug delivery when its composition is predictably tuned or deliberately modulated. We hypothesized that preloading apolipoprotein E (ApoE), previously identified as a constituent of the corona of β-sheet-breaker peptide-functionalized gold nanoparticles (AuNPs), would enhance transport across the blood-brain barrier (BBB) and increase brain uptake. To test this, we synthesized AuNPs (approximately 12 nm) functionalized (AuNP-f) with CLPFFD or THRPPMWSPVWPCLPFFD peptides, both containing the β-sheet-breaker motif LPFFD, which recognizes β-amyloid aggregates implicated in Alzheimer's disease. After incubation with human plasma, hard-corona proteins were profiled by 2D IEF/SDS-PAGE and LC-MS/MS. Proteins were ranked based on their roles in nanoparticle trafficking and BBB transcytosis, and ApoE was selected for deliberate enrichment due to its recurrent presence. ApoE-decorated AuNP-f were evaluated in an in vitro BBB model and in vivo biodistribution assays using Sprague-Dawley rats. Brain accumulation was assessed ex vivo. Preloading ApoE onto AuNP-f significantly enhanced nanoparticle transport across the BBB in vitro and increased brain accumulation in rats. These results demonstrate that rational corona enrichment with ApoE improves BBB transit and brain accumulation without altering nanoparticle surface chemistry. Corona engineering thus offers a pragmatic route to brain-targeted nanodrug delivery and may be extended to other protein-receptor axes for organ-specific targeting. Show less

Focal adhesions (FAs) connect inner workings of cell to the extracellular matrix to control cell adhesion, migration and mechanosensing. Previous studies demonstrated that FAs contain three vertical layers, which connect extracellular matrix to the cytoskeleton. By using super-resolution iPALM microscopy, we identify two additional nanoscale layers within FAs, specified by actin filaments bound to tropomyosin isoforms Tpm1.6 and Tpm3.2. The Tpm1.6-actin filaments, beneath the previously identified α-actinin cross-linked actin filaments, appear critical for adhesion maturation and controlled cell motility, whereas the adjacent Tpm3.2-actin filament layer beneath seems to facilitate adhesion disassembly. Mechanistically, Tpm3.2 stabilizes ACF-7/MACF1 and KANK-family proteins at adhesions, and hence targets microtubule plus-ends to FAs to catalyse their disassembly. Tpm3.2 depletion leads to disorganized microtubule network, abnormally stable FAs, and defects in tail retraction during migration. Thus, FAs are composed of distinct actin filament layers, and each may have specific roles in coupling adhesions to the cytoskeleton, or in controlling adhesion dynamics. Show less

The aim of this study was to evaluate the clinical course and outcomes of post-COVID myocarditis in patients with cardiomyopathies (CMP). This case series includes 10 patients with different CMPs who had COVID-19 (seven men; 48.4 ± 11.4 yr.): left ventricular non-compaction (n = 2), arrhythmogenic right ventricular CMP in combination with a heterozygous form of hemochromatosis (n = 1, Show less

Stem cells are defined by their ability to self-renew and differentiate, both shown in multiple studies to be regulated by metabolic processes. To decipher metabolic signatures of self-renewal in blastocyst-derived stem cells, we compared early differentiating embryonic stem cells (ESCs) and their extra-embryonic counterparts, trophoblast (T)SCs to their self-renewing counterparts. A metabolomics analysis pointed to the desaturation of fatty acyl chains as a metabolic signature of differentiating blastocyst-derived SCs via the upregulation of delta-6 desaturase (D6D; FADS2) and delta-5 desaturase (D5D; FADS1), key enzymes in the biosynthesis of polyunsaturated fatty acids (PUFAs). The inhibition of D6D or D5D by specific inhibitors or SiRNA retained stemness in ESCs and TSCs, and attenuated endoplasmic reticulum (ER) stress-related apoptosis. D6D inhibition in ESCs upregulated stearoyl-CoA desaturase-1 (Scd1), essential to maintain ER homeostasis. In TSCs, however, D6D inhibition downregulated Scd1. TSCs show higher Scd1 mRNA expression and high levels of monounsaturated fatty acyl chain products in comparison to ESCs. The addition of oleic acid, the product of Scd1 (essential for ESCs), to culture medium, was detrimental to TSCs. Interestingly, TSCs express a high molecular mass variant of Scd1 protein, hardly expressed by ESCs. Taken together, our data suggest that lipid desaturation is a metabolic regulator of the balance between differentiation and self-renewal of ESCs and TSCs. They point to lipid polydesaturation as a driver of differentiation in both cell types. Monounsaturated fatty acids (MUFAs), essential for ESCs are detrimental to TSCs. Show less

The same variants in sarcomeric genes can lead to different cardiomyopathies within the same family. This gave rise to the concept of a continuum of sarcomeric cardiomyopathies. However, the manifestations and evolution of these cardiomyopathies in pathogenic variant carriers, including members of the same family, remains poorly understood. We present a case of familial sarcomeric cardiomyopathy caused by heterozygous truncating pathogenic variant p.Q1233* in cardiac myosin-binding protein C ( Show less

Hypertrophic cardiomyopathy (HCM) is the most common inherited disease, with a prevalence of 1:200 worldwide. The cause of HCM usually presents with an autosomal dominant mutation in the genes encoding one of more than 20 sarcomeric proteins, incomplete penetrance, and variable expressivity. HCM classically manifests as an unexplained thickness of the interventricular septum (IVS) and left ventricular (LV) walls, with or without the obstruction of the LV outflow tract (LVOT), and variable cardiac arrhythmias. Here, we present a rare case of mixed cardiomyopathy (cardiac hypertrophy and dilation) and erythrocytosis in a young patient. A 27-year-old man was admitted to the clinic due to biventricular heart failure (HF) NYHA class III. Personal medical records included a diagnosis of dilated cardiomyopathy (DCM) since the age of 4 years and were, at the time, considered an outcome of myocarditis. Severe respiratory infection led to circulatory decompensation and acute femoral thrombosis. The combination of non-obstructive LV hypertrophy (LV walls up to 15 mm), LV dilatation, decreased contractility (LV EF 24%), and LV apical thrombosis were seen. Cardiac MRI showed a complex pattern of late gadolinium enhancement (LGE). Endomyocardial biopsy (EMB) revealed primary cardiomyopathy with intravascular coagulation and an inflammatory response. No viral genome was detected in the plasma or EMB samples. Whole exome sequencing (WES) revealed a homozygous in-frame deletion p.2711₂₇₃₇del in the Show less

Ovarian cancer is the most lethal gynecological malignancy. Currently, new chemotherapeutic strategies are required to improve patient outcome and survival. Biguanides, classic anti-diabetic drugs, have gained importance for theiri antitumor potency demonstrated by various studies. Olaparib is a PARP inhibitor approved for maintenance therapy following platinum-based chemotherapy. Furthermore, Snai1, a transcription factor that works as a master regulator of the epithelial/mesenchymal transition process (EMT) is involved in ovarian cancer resistance and progression. Here we aimed to demonstrate the possible cross talk between biguanides and Snail in response to olaparib combination therapy. In this study, we have shown that while in A2780CR cells biguanides reduced cell survival (single treatments ~20%; combined treatment ~44%) and cell migration (single treatments ~45%; biguanide-olaparib ~80%) significantly, A2780PAR exhibited superior efficacy with single (~60%) and combined treatments (~80%). Moreover, our results indicate that knock-down of Snail further enhances the attenuation of migration, inhibits EMT related-proteins (~90%) and induces a synergistic effect in biguanide-olaparib treatment. Altogether, this work suggests a novel treatment strategy against drug-resistant or recurrent ovarian cancer. Show less

Interstitial deletions of 11p13 involving MPPED2, DCDC5, DCDC1, DNAJC24, IMMP1L, and ELP4 are previously reported to have downstream transcriptional effects on the expression of PAX6, due to a downstream regulatory region (DRR). Currently, no clear genotype-phenotype correlations have been established allowing for conclusive information regarding the exact location of the PAX6 DRR, though its location has been approximated in mouse models to be within the Elp4 gene. Of the clinical reports currently published examining patients with intact PAX6 genes but harboring deletions identified in genes downstream of PAX6, 100% indicate phenotypes which include aniridia, whereas approximately half report additional eye deformities, autism, or intellectual disability. In this clinical report, we present a 12-year-old male patient, his brother, and mother with pericentric inversions of chromosome 11 associated with submicroscopic interstitial deletions of 11p13 and duplications of 11q22.3. The inversions were identified by standard cytogenetic analysis; microarray and FISH detected the chromosomal imbalance. The patient's phenotype includes intellectual disability, speech abnormalities, and autistic behaviors, but interestingly neither the patient, his brother, nor mother have aniridia or other eye anomalies. To the best of our knowledge, these findings in three family members represent the only reported cases with 11p13 deletions downstream of PAX6 not demonstrating phenotypic characteristics of aniridia or abnormal eye development. Although none of the deleted genes are obvious candidates for the patient's phenotype, the absence of aniridia in the presence of this deletion in all three family members further delineates the location of the DRR for PAX6. Show less