Autism patient-derived SHANK2BY29X mutation affects the development of ALDH1A1 negative dopamine neuron.

Autism spectrum disorder (ASD) encompasses a range of neurodevelopmental conditions. Different mutations on a single ASD gene contribute to heterogeneity of disease phenotypes, possibly due to functional diversity of generated isoforms. SHANK2, a causative gene in ASD, demonstrates this phenomenon, but there is a scarcity of tools for studying endogenous SHANK2 proteins in an isoform-specific manner. Here, we report a point mutation on SHANK2, which is found in a patient with autism, located on exon of the SHANK2B transcript variant (NM_133266.5), hereby SHANK2BY29X. This mutation results in an early stop codon and an aberrant splicing event that impacts SHANK2 transcript variants distinctly. Induced pluripotent stem cells (iPSCs) carrying this mutation, from the patient or isogenic editing, fail to differentiate into functional dopamine (DA) neurons, which can be rescued by genetic correction. Available SMART-Seq single-cell data from human midbrain reveals the abundance of SHANK2B transcript in the ALDH1A1 negative DA neurons. We then show that SHANK2BY29X mutation primarily affects SHANK2B expression and ALDH1A1 negative DA neurons in vitro during early neuronal developmental stage. Mice knocked in with the identical mutation exhibit autistic-like behavior, decreased occupancy of ALDH1A1 negative DA neurons and decreased dopamine release in ventral tegmental area (VTA). Our study provides novel insights on a SHANK2 mutation derived from autism patient and highlights SHANK2B significance in ALDH1A1 negative DA neuron.

High level expression and biochemical characterization of an alkaline serine protease from Geobacillus stearothermophilus to prepare antihypertensive whey protein hydrolysate.

BACKGROUND: Proteases are important for hydrolysis of proteins to generate peptides with many bioactivities. Thus, the development of novel proteases with high activities is meaningful to discover bioactive peptides. Because natural isolation from animal, plant and microbial sources is impractical to produce large quantities of proteases, gene cloning and expression of target protease are preferred. RESULTS: In this study, an alkaline serine protease gene (GsProS8) from Geobacillus stearothermophilus was successfully cloned and expressed in Bacillus subtilis. The recombinant GsProS8 was produced with high protease activity of 3807 U/mL after high cell density fermentation. GsProS8 was then purified through ammonium sulfate precipitation and a two-step chromatographic method to obtain the homogeneous protease. The molecular mass of GsProS8 was estimated to be 27.2 kDa by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and 28.3 kDa by gel filtration. The optimal activity of GsProS8 was found to be pH 8.5 and 50 °C, respectively. The protease exhibited a broad substrate specificity and different kinetic parameters to casein and whey protein. Furthermore, the hydrolysis of whey protein using GsProS8 resulted in a large amount of peptides with high angiotensin-I-converting enzyme (ACE) inhibitory activity (IC50 of 0.129 mg/mL). CONCLUSIONS: GsProS8 could be a potential candidate for industrial applications, especially the preparation of antihypertensive peptides.

Tectonic Proteins Are Important Players in Non-Motile Ciliopathies.

Primary cilium is a ubiquitous, tiny organelle on the apex of the mammalian cells. Non-motile (primary) ciliopathies are diseases caused by the dysfunction of the primary cilium and they are characterized by diverse clinical and genetic heterogeneity. To date, nearly 200 genes have been shown to be associated with primary ciliopathies. Among them, tectonic genes are the important causative genes of ciliopathies. Tectonic proteins including TCTN1, TCTN2, and TCTN3 are important component proteins residing at the transition zone of cilia. Indeed, many ciliopathies have been reported to involve tectonics mutations, highlighting a pivotal role for tectonic proteins in ciliary functions. However, the specific functions of tectonic proteins remain largely enigmatic. Herein, we discuss the recent advances on the localization and structure of tectonic proteins and the functions of tectonic proteins. The increasing line of evidences demonstrates that tectonic proteins are required for ciliogenesis and regulate ciliary membrane composition. More importantly, Tectonic proteins play a vital role in the regulation of the Sonic Hedgehog (Shh) pathway; Tectonic deficient mice show the Shh pathway-related developmental defects. Tectonic proteins share similar functions including neural patterning and Gli3 processing but also each has a unique and indispensable role in the ciliogenesis and signaling pathways. At the same time, the mutations of tectonic genes are the causes of a serial of primary ciliopathies including Meckel-Gruber syndrome, Oral-facial-digital syndrome, and Joubert syndrome. Therefore, full understanding of functions of tectonic proteins will help to crack ciliopathies and improve life quality of patients by future gene therapy.

Fisetin provides antidepressant effects by activating the tropomyosin receptor kinase B signal pathway in mice.

Depression has been associated with a low-grade chronic inflammatory state, suggesting a potential therapeutic role for anti-inflammatory agents. Fisetin is a naturally occurring flavonoid in strawberries that has anti-inflammatory activities, but whether fisetin has antidepressant effects is unknown. In this study, we exposed mice to spatial restraint for 2 weeks with or without treatment with fisetin. Immobility time in the forced swimming and tail suspension test after this restraint increased in the untreated group, but this increase did not occur in the fisetin group. We administered fisetin to Abelson helper integration site-1 (Ahi1) knockout mice, which have depressive phenotypes. We found that fisetin attenuated the depressive phenotype of these Ahi1 knockout mice. We further investigated the potential mechanism of fisetin's antidepressant effects. Because TrkB is a critical signaling pathway in the mechanisms of depression, we examined whether phosphorylated TrkB was involved in the antidepressant effects of fisetin. We found that fisetin increased phosphorylated TrkB level without altering total TrkB; this increase was attenuated by K252a, a specific TrkB inhibitor. Taken together, our results demonstrated that fisetin may have therapeutic potential for treating depression and that this antidepressant effect may be mediated by the activation of the TrkB signaling pathway.

Generative visual common sense: Testing analysis-by-synthesis on Mondrian-style image.

The well-known Mondrian-style images, aside from being aesthetically amusing, also reflect the core principles of human vision in their viewing experience. First, when we see a Mondrian-style image consisting only of a grid and primary colors, we may automatically interpret its causal history such that it was generated by recursively partitioning a blank scene. Second, the image we observe is open to many possible ways of partitioning, and their probabilities of dominating the interpretation can be captured by a probabilistic distribution. Moreover, the causal interpretation of a Mondrian-style image can emerge almost spontaneously, not being tailored to any specific task. Using Mondrian-style images as a case study, we demonstrate the generative nature of human vision by showing that a Bayesian model based upon an image-generation task can support a wide range of visual tasks with little retraining. Our model, learned from human-synthesized Mondrian-style images, could predict human performance in the perceptual complexity ranking, capture the transmission stability when images were iteratively passed among participants, and pass a visual Turing test. Our results collectively show that human vision is causal such that we interpret an image from the angle of how it was generated. The success of generalization with little retraining suggests that generative vision constitutes a type of common sense that supports a wide range of tasks of different natures. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Circadian disruption and sleep disorders in neurodegeneration.

Disruptions of circadian rhythms and sleep cycles are common among neurodegenerative diseases and can occur at multiple levels. Accumulating evidence reveals a bidirectional relationship between disruptions of circadian rhythms and sleep cycles and neurodegenerative diseases. Circadian disruption and sleep disorders aggravate neurodegeneration and neurodegenerative diseases can in turn disrupt circadian rhythms and sleep. Importantly, circadian disruption and various sleep disorders can increase the risk of neurodegenerative diseases. Thus, harnessing the circadian biology findings from preclinical and translational research in neurodegenerative diseases is of importance for reducing risk of neurodegeneration and improving symptoms and quality of life of individuals with neurodegenerative disorders via approaches that normalize circadian in the context of precision medicine. In this review, we discuss the implications of circadian disruption and sleep disorders in neurodegenerative diseases by summarizing evidence from both human and animal studies, focusing on the bidirectional links of sleep and circadian rhythms with prevalent forms of neurodegeneration. These findings provide valuable insights into the pathogenesis of neurodegenerative diseases and suggest a promising role of circadian-based interventions.

Generalized EEG Slowing Across Phasic REM Sleep, Not Subjective RBD Severity, Predicts Neurodegeneration in Idiopathic RBD.

Purpose: Idiopathic rapid eye movement sleep behavior disorder (iRBD) is the prodromal marker of α-synuclein degeneration with markedly high predictive value. We aim to evaluate the value of electroencephalography (EEG) data during rapid eye movement (REM) sleep and subjective RBD severity in predicting the conversion to neurodegenerative diseases in iRBD patients. Methods: At the baseline, iRBD patients underwent clinical assessment and video-polysomnography (PSG). Relative spectral power for nine frequency bands during phasic and tonic REM sleep in three regions of interest, slow-to-fast ratios, clinical and PSG variables were estimated and compared between iRBD patients who converted to neurodegenerative diseases (iRBD-C) and iRBD patients who remained disease-free (iRBD-NC). Receiver operating characteristic (ROC) curves evaluated the predictive performance of slow-to-fast ratios, and subjective RBD severity as assessed with RBD Questionnaire-Hong Kong. Results: Twenty-two (33.8%) patients eventually developed neurodegenerative diseases. The iRBD-C group showed shorter total sleep time (p < 0.001), lower stage 2 sleep percentage (p = 0.044), more periodic leg-movement-related arousal index (p = 0.004), increased tonic chin electromyelographic activity (p = 0.040) and higher REM density in the third REM episode (p = 0.034) than the iRBD-NC group. EEG spectral power analyses revealed that iRBD phenoconverters showed significantly higher delta and lower alpha power, especially in central and occipital regions during the phasic REM state compared to the iRBD-NC group. Significantly higher slow-to-fast ratios were observed in a more generalized way during the phasic state in the iRBD-C group compared to the iRBD-NC group. ROC analyses of the slowing ratio in occipital areas during phasic REM sleep yielded an area under the curve of 0.749 (p = 0.001), while no significant predictive value of subjective RBD severity was observed. Conclusion: Our study shows that EEG slowing, especially in a more generalized manner during the phasic period, may be a promising marker in predicting phenoconversion in iRBD, rather than subjective RBD severity.

Cognitive Performance is Associated with Altered Cerebral Hemodynamics Assessed by Transcranial Ultrasound in Parkinson's Disease.

Purpose: Cognitive impairment (CI) is a common but debilitating non-motor symptom in Parkinson's disease (PD). Although cerebrovascular functions are related to cognitive performance in healthy individuals, such a relation in PD remains elusive. This study aims to assess the association between cerebrovascular function and cognitive performance in PD individuals. Patients and Methods: Two-hundred-and-one PD individuals were retrospectively included. They were subsequently divided into two groups: PD with normal cognition (PD-NC) and PD with CI (PD-CI). Cerebral hemodynamic characteristics of the middle cerebral arteries were assessed by transcranial ultrasound. The association between scores in each cognitive domain and cerebral hemodynamic parameters was further analyzed using regression analyses. Additionally, a binary logistic regression model with backward stepwise procedure was applied to build the model for discriminating CI in PD individuals. An independent dataset of additional 46 PD individuals was used further. Results: The PD-CI group showed a relatively lower end-diastolic blood flow velocity (EDV, p < 0.05) and a higher resistive index (RI, p < 0.05) compared to the PD-NC group. RI showed significant associations with the memory item score of Montreal Cognitive Assessment (p < 0.05). A model combining clinical and hemodynamic variables was established with optimal efficiency (area under the curve, AUC = 0.651). Further replication of the model in an independent dataset yielded a great consistency (AUC = 0.704). Conclusion: In our study, cerebrovascular functions were significantly associated with the cognitive performance in PD individuals, especially with the memory task. The established model was effective in identifying CI in PD individuals, which might be a potentially useful tool to screen the cognitive decline in PD individuals at an early stage of the disease. Further studies with larger sample sizes in different populations are warranted.

Canagliflozin could improve the levels of renal oxygenation in newly diagnosed type 2 diabetes patients with normal renal function.

OBJECTIVE: To evaluate the effects of canagliflozin on the renal oxygen level and blood perfusion in newly diagnosed type 2 diabetes mellitus (T2DM) patients with normal renal function. METHODS: We conducted a prospective, randomised, and drug-controlled trial to determine the reno-protective effect exerted by canagliflozin in newly diagnosed T2DM patients with normal renal function using blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) and arterial spin labelling MRI (ASL-MRI). This provides an experimental basis for a first-line of defence for the prevention of diabetic nephropathy. RESULTS: Canagliflozin induced a significant decrease in body weight and diastolic blood pressure compared with glimepiride (all p < 0.05). The high baseline mean estimated glomerular filtration rate (eGFR) in both groups was indicative of a GFR level at a relatively high status that was significantly alleviated after 24 weeks of canagliflozin treatment (change from baseline, p = 0.04, and change versus glimepiride control, p = 0.048). However, neither drug regimen significantly affected renal blood perfusion. The R2* values were inversely proportional to the tissue oxygen content. Compared to the baseline, 24 weeks of canagliflozin treatment decreased the R2* values of the renal cortex and medulla by 22.3% (p = 0.005) and 29.2% (p = 0.0002) respectively, and these decreases were significantly greater than in the glimepiride control group (p = 0.0004 and p = 0.02). CONCLUSIONS: Canagliflozin improved the levels of renal oxygenation in newly diagnosed T2DM patients with normal renal function independent of changes in renal blood perfusion.

Light therapy: a new option for neurodegenerative diseases.

ABSTRACT: Given the increasing incidence of neurodegenerative disease (ND), recent research efforts have intensified the search for curative treatments. Despite significant research, however, existing therapeutic options for ND can only slow down the progression of the disease, but not provide a cure. Light therapy (LT) has been used to treat some mental and sleep disorders. This review illustrates recent studies of the use of LT in patients with ND and highlights its potential for clinical applications. The literature was collected from PubMed through June 2020. Selected studies were primarily English articles or articles that could be obtained with English abstracts and Chinese main text. Articles were not limited by type. Additional potential publications were also identified from the bibliographies of identified articles and the authors' reference libraries. The identified literature suggests that LT is a safe and convenient physical method of treatment. It may alleviate sleep disorders, depression, cognitive function, and other clinical symptoms. However, some studies have reported limited or no effects. Therefore, LT represents an attractive therapeutic approach for further investigation in ND. LT is an effective physical form of therapy and a new direction for research into treatments for ND. However, it requires further animal experiments to elucidate mechanisms of action and large, double-blind, randomized, and controlled trials to explore true efficacy in patients with ND.

Uncovering the Functional Link Between SHANK3 Deletions and Deficiency in Neurodevelopment Using iPSC-Derived Human Neurons.

SHANK3 mutations, including de novo deletions, have been associated with autism spectrum disorders (ASD). However, the effects of SHANK3 loss of function on neurodevelopment remain poorly understood. Here we generated human induced pluripotent stem cells (iPSC) in vitro, followed by neuro-differentiation and lentivirus-mediated shRNA expression to evaluate how SHANK3 knockdown affects the in vitro neurodevelopmental process at multiple time points (up to 4 weeks). We found that SHANK3 knockdown impaired both early stage of neuronal development and mature neuronal function, as demonstrated by a reduction in neuronal soma size, growth cone area, neurite length and branch numbers. Notably, electrophysiology analyses showed defects in excitatory and inhibitory synaptic transmission. Furthermore, transcriptome analyses revealed that multiple biological pathways related to neuron projection, motility and regulation of neurogenesis were disrupted in cells with SHANK3 knockdown. In conclusion, utilizing a human iPSC-based neural induction model, this study presented combined morphological, electrophysiological and transcription evidence that support that SHANK3 as an intrinsic, cell autonomous factor that controls cellular function development in human neurons.

A novel aspartic protease from Rhizomucor miehei expressed in Pichia pastoris and its application on meat tenderization and preparation of turtle peptides.

A novel aspartic protease gene (RmproA) was cloned from the thermophilic fungus Rhizomucor miehei CAU432 and expressed in Pichia pastoris. The RmproA was successfully expressed in P. pastoris as an active extracellular protease. High protease activity of 3480.4 U/mL was obtained by high cell-density fermentation. The protease was purified by the two step protocols to homogeneity. The molecular mass of the RmproA was estimated to be 52.4 kDa by SDS-PAGE and 50.6 kDa by gel filtration. The purified enzyme was optimally active at pH 5.5 and 55 °C, respectively. The enzyme exhibited a broad range of substrate specificity. RmproA-treated pork muscle showed lower shear force than papain-treated sample at a relative low concentration, suggesting its effectiveness on meat tenderization. Moreover, turtle hydrolysis by RmproA resulted in a large amount of small peptides, which exhibited high ACE-inhibitory activity. Thus, RmproA may be a potential candidate for several industrial applications.

Loss of Tctn3 causes neuronal apoptosis and neural tube defects in mice.

Tctn3 belongs to the Tectonic (Tctn) family and is a single-pass membrane protein localized at the transition zone of primary cilia as an important component of ciliopathy-related protein complexes. Previous studies showed that mutations in Tctn1 and Tctn2, two members of the tectonic family, have been reported to disrupt neural tube development in humans and mice, but the functions of Tctn3 in brain development remain elusive. In this study, Tctn3 knockout (KO) mice were generated by utilizing the piggyBac (PB) transposon system. We found that Tctn3 KO mice exhibited abnormal global development, including prenatal lethality, microphthalmia, polysyndactyly, and abnormal head, sternum, and neural tube, whereas Tctn3 heterozygous KO mice did not show abnormal development or behaviors. Further, we found that the mRNA levels of Gli1 and Ptch1, downstream signaling components of the Shh pathway, were significantly reduced. Likewise, neural tube patterning-related proteins, such as Shh, Foxa2, and Nkx2.2, were altered in their distribution. Interestingly, Tctn3 KO led to significant changes in apoptosis-related proteins, including Bcl-2, Bax, and cleaved PARP1, resulting in reduced numbers of neuronal cells in embryonic brains. Tctn3 KO inhibited the PI3K/Akt signaling pathway but not the mTOR-dependent pathway. The small molecule SC79, a specific Akt activator, blocked apoptotic cell death in primary mouse embryonic fibroblasts from Tctn3 KO mice. Finally, NPHP1, a protein with anti-apoptotic ability, was found to form a complex with Tctn3, and its levels were decreased in Tctn3 KO mice. In conclusion, our results show that Tctn3 KO disrupts the Shh signaling pathway and neural tube patterning, resulting in abnormal embryonic development, cellular apoptosis, and prenatal death in mice.

Characteristic analyses of a neural differentiation model from iPSC-derived neuron according to morphology, physiology, and global gene expression pattern.

Induced pluripotent stem cells (iPSCs) can differentiate into neural progenitor cells (NPC) under proper conditions. NPC can be used as a model and is a useful tool for disease mechanism exploration and drug screening. However, the characteristics of the cells in various stages from NPC to functional neurons have not been fully described. This study investigated the characteristics of iPSC-derived NPCs during differentiation. Morphological characteristics of the NPCs, including soma area, neurite length, and the number of neurite branches, were examined on selected differentiation days. Physiological functions were assessed by recordings of sodium current, spontaneous excitatory postsynaptic current (sEPSC), and spontaneous inhibitory postsynaptic current (sIPSC). Furthermore, gene expression patterns were assessed with RNA-seq. We found that NPCs derived from iPSCs can be differentiated into glutamatergic and gabaergic neurons. Cell growth peaked during differentiation day 7-12, as the soma area decreased after day 12, growth cone and the number of branches peaked at day 9 and decreased afterwards; whereas a functional synapse formed after day 23. RNA-seq analysis found that a differential expression pattern emerged by day 7. Overall, the study provides a framework for the differentiation process of hiPSC-derived NPCs.

Long-read sequencing and de novo assembly of a Chinese genome.

Short-read sequencing has enabled the de novo assembly of several individual human genomes, but with inherent limitations in characterizing repeat elements. Here we sequence a Chinese individual HX1 by single-molecule real-time (SMRT) long-read sequencing, construct a physical map by NanoChannel arrays and generate a de novo assembly of 2.93 Gb (contig N50: 8.3 Mb, scaffold N50: 22.0 Mb, including 39.3 Mb N-bases), together with 206 Mb of alternative haplotypes. The assembly fully or partially fills 274 (28.4%) N-gaps in the reference genome GRCh38. Comparison to GRCh38 reveals 12.8 Mb of HX1-specific sequences, including 4.1 Mb that are not present in previously reported Asian genomes. Furthermore, long-read sequencing of the transcriptome reveals novel spliced genes that are not annotated in GENCODE and are missed by short-read RNA-Seq. Our results imply that improved characterization of genome functional variation may require the use of a range of genomic technologies on diverse human populations.