Parkinson's disease is the second most common neurodegenerative disorder. Although the pathogenesis of Parkinson's disease is not entirely clear, the aberrant aggregation of α-synuclein has long been ...considered as an important risk factor. Elucidating the mechanisms that influence the aggregation of α-synuclein is essential for developing an effective diagnostic, preventative and therapeutic strategy to treat this devastating disease. The aggregation of α-synuclein is influenced by several post-translational modifications. Here, we summarized the major post-translational modifications (phosphorylation, ubiquitination, truncation, nitration,
-GlcNAcylation) of α-synuclein and the effect of these modifications on α-synuclein aggregation, which may provide potential targets for future therapeutics.
The circadian clock is generated by a molecular timekeeping mechanism coordinating daily oscillations of physiology and behaviors in mammals. In the mammalian circadian clockwork, basic ...helix–loop–helix ARNT‐like protein 1 (BMAL1) is a core circadian component whose defects lead to circadian disruption and elicit behavioral arrhythmicity. To identify previously unknown regulators for circadian clocks, we searched for genes influencing BMAL1 protein level by using a CRISPR/Cas9‐based genome‐wide knockout library. As a result, we found that the deubiquitinase ubiquitin carboxyl‐terminal hydrolase 1 (USP1) positively affects BMAL1 protein abundance. Overexpression of wild‐type USP1, but not a deubiquitinase‐inactive mutant USP1, upregulated BMAL1 protein level, whereas genetic ablation of USP1 downregulated BMAL1 protein level in U2OS cells. Furthermore, treatment with USP1 inhibitors led to significant downregulation of BMAL1 protein in U2OS cells as well as mouse tissues. Subsequently, genetic ablation or pharmacological inhibition of USP1 resulted in reduced mRNA levels of a panel of clock genes and disrupted circadian rhythms in U2OS cells. Mechanistically, USP1 was able to de‐ubiquitinate BMAL1 and inhibit the proteasomal degradation of BMAL1. Interestingly, the expression of Usp1 was much higher than the other two deubiquitinases of BMAL1 (Usp2 and Usp9X) in the mouse heart, implying a tissue‐specific function of USP1 in the regulation of BMAL1 stability. Our work thus identifies deubiquitinase USP1 as a previously unknown regulator of the mammalian circadian clock and highlights the potential of genome‐wide CRISPR screens in the identification of regulators for the circadian clock.
The circadian clock regulates mammalian physiology and behavior, and its disruptions have been implicated in various diseases. To investigate the regulatory network of the core circadian component BMAL1, Lu and colleagues performed a genome‐wide CRISPR/Cas9 knockout screen. They unveiled the ubiquitin hydrolase USP1 as a novel regulator of BMAL1 expression. USP1 can de‐ubiquitinate BMAL1, effectively inhibiting its proteasomal degradation. Furthermore, knockdown of USP1 led to a significant reduction in clock gene expression and caused disruptions in circadian clocks. This work additionally demonstrated the utility of genome‐wide knockout screens for studying the complex regulation of the circadian clock.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Objectives
Branchio‐oto‐renal (BOR) syndrome is characterized by branchial defects, hearing loss, preauricular pits, and renal anomalies, whereas patients with all symptoms except renal defects are ...diagnosed as branchio‐oto (BO) syndrome. BOR/BO is one of the most common forms of autosomal dominant syndromic hearing loss, and EYA1 is the major causative gene. In this study, clinical and genetic analyses as well as auditory rehabilitation were performed in a Chinese family with BOR/BO syndrome.
Methods
Three affected individuals from a Chinese family were analyzed by whole exome sequencing (WES) to analyze the single nucleotide variants and copy number variations (CNVs). Whole genome sequencing was used to identify the breakpoints of CNVs; and quantitative polymerase chain reaction was utilized to verify the CNVs. Furthermore, cochlea implantation was performed in one patient to reconstruct hearing.
Results
A heterozygous 2.69 Mb deletion at chromosome 8q13 (chr8: 69582185‐72275725) cosegregates with the BOR/BO symptoms in this family, resulting in heterozygous loss of the EYA1 gene. In addition to typical BOR/BO symptoms, epilepsy or gastroesophageal reflux was observed in some patients. Cochlear implantation resulted in significant hearing improvement in one patient.
Conclusions
A novel deletion involving the whole EYA1 gene was identified by WES. To the best of our knowledge, epilepsy or gastroesophageal reflux was reported in BOR/BO patients for the first time, which expanded the BOR/BO phenotypes spectrum. Successful auditory rehabilitation can be achieved with cochlear implantations in some BOR/BO patients.
Level of Evidence
4 Laryngoscope, 130:526–532, 2020
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
Circadian clocks are endogenous oscillators that control ∼24-hour physiology and behaviors in virtually all organisms. The circadian oscillator comprises interconnected transcriptional and ...translational feedback loops, but also requires finely coordinated protein homeostasis including protein degradation and maturation. However, the mechanisms underlying the mammalian clock protein maturation is largely unknown. In this study, we demonstrate that necdin, one of the Prader-Willi syndrome (PWS)-causative genes, is highly expressed in the suprachiasmatic nuclei (SCN), the pacemaker of circadian clocks in mammals. Mice deficient in necdin show abnormal behaviors during an 8-hour advance jet-lag paradigm and disrupted clock gene expression in the liver. By using yeast two hybrid screening, we identified BMAL1, the core component of the circadian clock, and co-chaperone SGT1 as two necdin-interactive proteins. BMAL1 and SGT1 associated with the N-terminal and C-terminal fragments of necdin, respectively. Mechanistically, necdin enables SGT1-HSP90 chaperone machinery to stabilize BMAL1. Depletion of necdin or SGT1/HSP90 leads to degradation of BMAL1 through the ubiquitin–proteasome system, resulting in alterations in both clock gene expression and circadian rhythms. Taken together, our data identify the PWS-associated protein necdin as a novel regulator of the circadian clock, and further emphasize the critical roles of chaperone machinery in circadian clock regulation.
Increased collagen expression and deposition are associated with cancer progression and poor prognosis in breast cancer patients. However, function and regulation of membrane-associated collagen in ...breast cancer have not been determined. Collagen XIII is a type II transmembrane protein within the collagen superfamily. Experiments in tissue culture and knockout mouse models show that collagen XIII is involved in cell adhesion and differentiation of certain cell types. In the present study, we determined roles of collagen XIII in breast cancer progression and metastasis.
We analyzed the association of collagen XIII expression with breast cancer development and metastasis using published gene expression profiles generated from human breast cancer tissues. Utilizing gain- and loss- of function approaches and 3D culture assays, we investigated roles of collagen XIII in regulating invasive tumor growth. Using the tumorsphere/mammosphere formation assay and the detachment cell culture assay, we determined whether collagen XIII enhances cancer cell stemness and induces anoikis resistance. We also inhibited collagen XIII signaling with β1 integrin function-blocking antibody. Finally, using the lung colonization assay and the orthotopic mammary tumor model, we investigated roles of collagen XIII in regulating breast cancer colonization and metastasis. Cox proportional hazard (log-rank) test, two-sided Student's t-test (two groups) and one-way ANOVA (three or more groups) analyses were used in this study.
Collagen XIII expression is significantly higher in human breast cancer tissue compared with normal mammary gland. Increased collagen XIII mRNA levels in breast cancer tissue correlated with short distant recurrence free survival. We showed that collagen XIII expression promoted invasive tumor growth in 3D culture, enhanced cancer cell stemness, and induced anoikis resistance. Collagen XIII expression induced β1 integrin activation. Blocking β1 integrin activation significantly reduced collagen XIII-induced invasion and mammosphere formation. Importantly, silencing collagen XIII in MDA-MB-231 cells reduced lung colonization and metastasis.
Our results demonstrate a novel function of collagen XIII in promoting cancer metastasis, cell invasion, and anoikis resistance.
Autism spectrum disorders (ASD) form a heterogeneous, neurodevelopmental syndrome characterized by deficits in social interactions and repetitive behavior/restricted interests. Dysregulation of mTOR ...signaling has been implicated in the pathogenesis of certain types of ASD, and inhibition of mTOR by rapamycin has been demonstrated to be an effective therapeutics for impaired social interaction in Tsc1+/-, Tsc2+/-, Pten-/- mice and valproic acid-induced ASD animal models. However, it is still unknown if dysregulation of mTOR signaling is responsible for the ASD-related deficit caused by other genes mutations. Contactin associated protein-like 2 (CNTNAP2) is the first widely replicated autism-predisposition gene. Mice deficient in Cntnap2 (Cntnap2-/- mice) show core ASD-like phenotypes, and have been demonstrated as a validated model for ASD-relevant drug discovery. In this study, we found hyperactive Akt-mTOR signaling in the hippocampus of Cntnap2-/- mice with RNA sequencing followed with biochemical analysis. Treatment with Akt inhibitor LY294002 or mTOR inhibitor rapamycin rescued the social deficit, but had no effect on hyperactivity and repetitive behavior/restricted behavior in Cntnap2-/- mice. We further showed that the effect of LY294002 and rapamycin on social behaviors is reversible. Our results thus identified hyperactive Akt-mTOR signaling pathway as a therapeutic target for abnormal social behavior in patients with dysfunction of CNTNAP2.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Breast cancer development is associated with macrophage infiltration and differentiation in the tumor microenvironment. Our previous study highlights the crucial function of reactive oxygen species ...(ROS) in enhancing macrophage infiltration during the disruption of mammary tissue polarity. However, the regulation of ROS and ROS-associated macrophage infiltration in breast cancer has not been fully determined. Previous studies identified retinoid orphan nuclear receptor alpha (RORα) as a potential tumor suppressor in human breast cancer. In the present study, we showed that retinoid orphan nuclear receptor alpha (RORα) significantly decreased ROS levels and inhibited ROS-mediated cytokine expression in breast cancer cells. RORα expression in mammary epithelial cells inhibited macrophage infiltration by repressing ROS generation in the co-culture assay. Using gene co-expression and chromatin immunoprecipitation (ChIP) analyses, we identified complex I subunits NDUFS6 and NDUFA11 as RORα targets that mediated its function in suppressing superoxide generation in mitochondria. Notably, the expression of RORα in 4T1 cells significantly inhibited cancer metastasis, reduced macrophage accumulation, and enhanced M1-like macrophage differentiation in tumor tissue. In addition, reduced RORα expression in breast cancer tissue was associated with an increased incidence of cancer metastasis. These results provide additional insights into cancer-associated inflammation, and identify RORα as a potential target to suppress ROS-induced mammary tumor progression.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Isolated hypogonadotropic hypogonadism (IHH) is a rare disorder characterized by impaired sexual development and infertility, caused by the deficiency of hypothalamic gonadotropin‐releasing hormone ...neurons. IHH is named Kallmann's syndrome (KS) or normosmic IHH (nIHH) when associated with a defective or normal sense of smell. Variants in SEMA3A have been recently identified in patients with KS. In this study, we screened SEMA3A variants in a cohort of Chinese patients with IHH by whole exome sequencing. Three novel heterozygous SEMA3A variants (R197Q, R617Q and V458I) were identified in two nIHH and one KS patients, respectively. Functional studies indicated that R197Q and R617Q variants were ineffective in activating the phosphorylation of FAK (focal adhesion kinase) in GN11 cells, despite normal production and secretion in HEK293T cells. The V458I SEMA3A had defect in secretion as it was not detected in the conditioned medium from HEK293T cells. Compared with wild type SEMA3A protein, all three SEMA3A mutant proteins were ineffective in inducing the migration of GN11 cells. Our study further showed the contribution of SEMA3A loss‐of‐function variants to the pathogenesis of IHH.
In this study, we identified three novel SEMA3A mutations in three unrelated Chinese IHH patients by exome sequencing. Functional studies indicated that the three mutant proteins led to reduction of FAK phosphorylation level in GN11 cells, and could not induce effective migration of GN11 cells. Furthermore, the V458I mutant protein had secretory defects.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
Purpose
Idiopathic hypogonadotropic hypogonadism (IHH) and CHARGE (C, coloboma; H, heart abnormalities; A, choanal atresia, R, retardation of growth and/or development; G, gonadal defects; ...E, ear deformities and deafness) syndrome are 2 distinct developmental disorders sharing features of hypogonadism and/or impaired olfaction. CHD7 variants contribute to >60% CHARGE syndrome and ~10% IHH patients. A variety of extended CHARGE-like features are frequently reported in CHARGE patients harboring CHD7 variants. In this study, we aimed to systematically analyze the diagnostic CHARGE features and the extended CHARGE-like features in patients with IHH with CHD7 variants.
Methods
Rare sequencing variants (RSVs) in CHD7 were identified through exome sequencing in 177 IHH probands. Detailed phenotyping was performed in the IHH patients harboring CHD7 variants and their available family members.
Results
CHD7 RSVs were identified in 10.2% (18/177) of the IHH probands. Two diagnostic CHARGE features, hearing loss and ear deformities, were significantly enriched in patients with CHD7 variants. Furthermore, CHD7 variants were significantly associated with a panel of extended CHARGE-like phenotypes, including mild ocular defects, dyspepsia/gastroesophageal reflux disease and skeletal defects. We also developed a predictive model for prioritizing CHD7 genetic testing in IHH patients.
Conclusion
CHD7 variants rarely cause isolated IHH. Surveillance of symptoms in CHARGE syndrome-affected organs will facilitate the proper treatment for these patients. Certain clinical features can be useful for prioritizing CHD7 genetic screening.
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