👤 Yin Hoe Yau

Maternal physical activity during pregnancy has been shown to confer benefits on the brain functions of offspring. This study investigated the positive effects of maternal exercise during pregnancy on enhancing hippocampal synaptic plasticity and resilience to stress-induced depressive behavior in adult murine offspring. Using a mouse model with mother mice engaged in voluntary wheel running during pregnancy, we assessed changes in long-term potentiation (LTP) in the hippocampal dentate gyrus, synaptic protein expression, and behavioral responses to chronic stress in adult male and female offspring from exercised dams compared with those from sedentary dams. We found that maternal exercise enhanced LTP in offspring of both sexes. Western blot analysis of hippocampal synaptoneurosome extractions revealed significant main effects of maternal exercise on increasing the expression of brain-derived neurotrophic factor (BDNF), PSD-95, synaptophysin, and phosphorylation of N-methyl-D-aspartate receptor subunit GluN2A and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit GluA1. Maternal exercise significantly increased synaptophysin levels in both male and female offspring, with sex-specific effects on increasing PSD-95 levels in male offspring and increased p-GluN2A levels in female offspring from exercised dams. Golgi staining revealed a significant increase in hippocampal dendritic spine density in female offspring only. Maternal exercise-induced improvements in hippocampal synaptic plasticity were associated with reduced depression-like behaviors in both male and female offspring exposed to chronic unpredictable stress. Additionally, male offspring displayed reduced anxiety-like behavior, while female offspring showed no significant anxiolytic changes. These findings elucidate the sex-specific effects of maternal exercise on enhancing hippocampal synaptic plasticity, which may contribute to increased resilience against stress-induced depressive behaviors in adult offspring. Show less

Glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1) is critical for transporting lipoprotein lipase (LPL) to the capillary lumen, where LPL breaks down triglycerides in triglyceride-rich lipoproteins. We herein report a 12-year-old Chinese girl who presented with severe hypertriglyceridemia and a recent diagnosis of systemic lupus erythematosus (SLE). She was first noted to have severe hypertriglyceridemia at 8.5 years old, complicated by three episodes of acute pancreatitis within 2 years. Between these episodes, her plasma triglycerides remained elevated, but at lower levels. Next-generation sequencing for primary hypertriglyceridemia yielded no significant findings. Investigations for secondary causes, to include fasting glucose, HbA1c, and thyroid function testing, were unrevealing. Given the fluctuating triglyceride levels and negative genetic testing for primary hypertriglyceridemia in the background of SLE, autoimmune hypertriglyceridemia was suspected. The diagnosis of GPIHBP1 autoantibody syndrome was confirmed by an elevated GPIHBP1 autoantibody titer and a low LPL mass in her serum. Her SLE was well controlled with immunosuppressants and belimumab. Fenofibrate and omega-3 fatty acids, which were initially prescribed for her hypertriglyceridemia, were later discontinued. The GPIHBP1 autoantibody and LPL mass normalized 2 years after diagnosis. This case illustrates hypertriglyceridemia caused by a rare disease entity associated with autoantibodies against the GPIHBP1 protein. This entity is worth considering after excluding genetic and common secondary causes of hypertriglyceridemia, particularly in a patient with a history of autoimmune disease. Show less

Autism spectrum disorders (ASD) comprise many complex and clinically distinct neurodevelopmental conditions, with increasing evidence linking them to parkinsonism. We searched Medline and Embase from inception to 21 March 2022 and reviewed the bibliographies of relevant articles. Studies were screened and reviewed comprehensively by two independent authors. Of 863 references from our search, we included eight clinical studies, nine genetic studies, and five case reports. Regardless of age group, Parkinson's disease (PD) and parkinsonian syndromes were more frequently observed in patients with ASD, though the evidence for increased rates of parkinsonism is less clear for children and adolescents. Parkinsonian features and hypokinetic behavior were common in Rett syndrome, with prevalence estimates ranging from 40% to 80%. Frequently observed parkinsonian features include bradykinesia, rigidity, hypomimia, and gait freezing. PD gene PARK2 copy number variations appear more frequently in ASD cases than controls. Evidence suggests that RIT2 and CD157/BST1 are implicated in ASD and PD, while the evidence for other PD-related genes (DRD2, GPCR37, the SLC gene family, and SMPD1) is less clear. Rare mutations, such as ATP13A2, CLN3, and WDR45, could result in autistic behavior and concomitant parkinsonism. The prevalence of parkinsonism in ASD is substantially greater than in the general population or matched controls. Various PD-associated gene loci, especially PARK2, could confer susceptibility to ASD as well. Important future directions include conducting prospective cohort studies to understand how parkinsonian symptoms may progress, genetic studies to reveal relevant gene loci, and pathophysiologic studies to identify potential therapeutic targets. Show less

Angiopoietin-like 4 (ANGPTL4) is a secretory protein that can be cleaved to form an N-terminal and a C-terminal protein. Studies performed thus far have linked ANGPTL4 to several cancer-related and metabolic processes. Notably, several point mutations in the C-terminal ANGPTL4 (cANGPTL4) have been reported, although no studies have been performed that ascribed these mutations to cancer-related and metabolic processes. In this study, we compared the characteristics of tumors with and without wild-type (wt) cANGPTL4 and tumors with cANGPTL4 bearing the T266M mutation (T266M cANGPTL4). We found that T266M cANGPTL4 bound to integrin α5β1 with a reduced affinity compared to wt, leading to weaker activation of downstream signaling molecules. The mutant tumors exhibited impaired proliferation, anoikis resistance, and migratory capability and had reduced adenylate energy charge. Further investigations also revealed that cANGPTL4 regulated the expression of Glut2. These findings may explain the differences in the tumor characteristics and energy metabolism observed with the cANGPTL4 T266M mutation compared to tumors without the mutation. Show less

We investigated the mutational landscape of mammalian target of rapamycin (mTOR) signalling cascade in hepatocellular carcinomas (HCCs) with chronic HBV background, aiming to evaluate and delineate mutation-dependent mechanism of mTOR hyperactivation in hepatocarcinogenesis. We performed next-generation sequencing on human HCC samples and cell line panel. Systematic mutational screening of mTOR pathway-related genes was undertaken and mutant genes were evaluated based on their recurrence. Protein expressions of tuberous sclerosis complex (TSC)1, TSC2 and pRPS6 were assessed by immunohistochemistry in human HCC samples. Rapamycin sensitivity was estimated by colony-formation assay in HCC cell lines and the treatment was further tested using our patient-derived tumour xenograft (PDTX) models. We identified and confirmed multiple mTOR components as recurrently mutated in HBV-associated HCCs. Of significance, we detected frequent (16.2%, n=18/111) mutations of Taken together, our findings suggest the significance of previously undocumented mutation-dependent mTOR hyperactivation and frequent Show less

In cultured vertebrate neurons, axons have a uniform arrangement of microtubules with plus-ends distal to the cell body (plus-end-out), whereas dendrites contain mixed polarity orientations with both plus-end-out and minus-end-out oriented microtubules. Rather than non-uniform microtubules, uniparallel minus-end-out microtubules are the signature of dendrites in Drosophila and Caenorhabditis elegans neurons. To determine whether mixed microtubule organization is a conserved feature of vertebrate dendrites, we used live-cell imaging to systematically analyze microtubule plus-end orientations in primary cultures of rat hippocampal and cortical neurons, dentate granule cells in mouse organotypic slices, and layer 2/3 pyramidal neurons in the somatosensory cortex of living mice. In vitro and in vivo, all microtubules had a plus-end-out orientation in axons, whereas microtubules in dendrites had mixed orientations. When dendritic microtubules were severed by laser-based microsurgery, we detected equal numbers of plus- and minus-end-out microtubule orientations throughout the dendritic processes. In dendrites, the minus-end-out microtubules were generally more stable and comparable with plus-end-out microtubules in axons. Interestingly, at early stages of neuronal development in nonpolarized cells, newly formed neurites already contained microtubules of opposite polarity, suggesting that the establishment of uniform plus-end-out microtubules occurs during axon formation. We propose a model in which the selective formation of uniform plus-end-out microtubules in the axon is a critical process underlying neuronal polarization. Live-cell imaging was used to systematically analyze microtubule organization in primary cultures of rat hippocampal neurons, dentate granule cells in mouse organotypic slices, and layer 2/3 pyramidal neuron in somatosensory cortex of living mice. In vitro and in vivo, all microtubules have a plus-end-out orientation in axons, whereas microtubules in dendrites have mixed orientations. Interestingly, newly formed neurites of nonpolarized neurons already contain mixed microtubules, and the specific organization of uniform plus-end-out microtubules only occurs during axon formation. Based on these findings, the authors propose a model in which the selective formation of uniform plus-end-out microtubules in the axon is a critical process underlying neuronal polarization. Show less

The clinically and genetically heterogenous foetal akinesias have low rates of genetic diagnosis. Exome sequencing of two siblings with phenotypic lethal multiple pterygium syndrome identified compound heterozygozity for a known splice site mutation (c.691+2T>C) and a novel missense mutation (c.956A>G; p.His319Arg) in glycogen branching enzyme 1 (GBE1). GBE1 mutations cause glycogen storage disease IV (GSD IV), including a severe foetal akinesia sub-phenotype. Re-investigating the muscle pathology identified storage material, consistent with GSD IV, which was confirmed biochemically. This study highlights the power of exome sequencing in genetically heterogeneous diseases and adds multiple pterygium syndrome to the phenotypic spectrum of GBE1 mutation. Show less