Ubiquitin Carboxy-terminal Hydrolase L1 Expression Research Articles

A RANKL-UCHL1-sCD13 negative feedback loop limits osteoclastogenesis in subchondral bone to prevent osteoarthritis progression

Abnormal subchondral bone remodeling plays a pivotal role in the progression of osteoarthritis (OA). Here, we analyzed subchondral bone samples from OA patients and observed a significant upregulation of ubiquitin carboxy-terminal hydrolase L1 (UCHL1) specifically in subchondral bone osteoclasts. Notably, we found a strong correlation between UCHL1 expression and osteoclast activity in the subchondral bone during OA progression in both human and murine models. Conditional UCHL1 deletion in osteoclast precursors exacerbated OA progression, while its overexpression, mediated by adeno-associated virus 9, alleviated this process in male mice. Mechanistically, RANKL stimulates UCHL1 expression in osteoclast precursors, subsequently stabilizing CD13, augmenting soluble CD13 (sCD13) release, and triggering an autocrine inhibitory effect on the MAPK pathway, thereby suppressing osteoclast formation. These findings unveil a previously unidentified negative feedback loop, RANKL-UCHL1-sCD13, that modulates osteoclast formation and presents a potential therapeutic target for OA.

UCHL1-PKM2 axis dysregulation is associated with promoted proliferation and invasiveness of urothelial bladder cancer cells.

Bladder cancer is one of the most common type of cancers globally, and the majority of cases belong to urothelial bladder carcinoma (UBC) type. Current researches have demonstrated that multiple genomic abnormalities are related to the sensitivity of cisplatin-based chemotherapy in bladder cancer patients. Previous findings have indicated a controversial role of Ubiquitin Carboxy-Terminal Hydrolase L1 (UCHL1) in malignancy, so we aimed to further explore the role of UCHL1 in UBC. UBC cell lines and The Cancer Genome Atlas (TCGA) in-silico datasets were utilized to investigate UCHL1 expression pattern and functional as well as prognostic impacts in UBC cancer cell line models and patients. UCHL1 overexpression and silencing vectors and subsequent immunoprecipitation/ubiquitination experiments in combination of cellular functional assays were conducted to explore UCHL1-PKM2 interaction axis and its significance in UBC malignancy. UCHL1 was significantly up-regulated in UBC cancer cells and UCHL1 high-expression was associated with higher pathology/clinical grade and significantly inferior overall prognosis of UBC patients. UCHL1 interacted with PKM2 and enhanced PKM2 protein level through inhibition of PKM2 protein degradation via ubiquitination process. UCHL1-PKM2 interaction significantly promoted UBC cellular proliferation, metastasis and invasion activities. UCHL1-PKM2 interaction played an interesting role in UBC tumor cell proliferation, migration and metastasis. Our study suggests PKM2-targeted treatment might have a potential value in metastatic malignancy therapy development in the future.

Increased expression of ubiquitin C-terminal hydrolase L1 in astrocytomas of ascending grades.

The ubiquitin-proteasome pathway controls the monitoring and degradation of important proteins and is involved in several cellular processes, such as development, differentiation, and transcriptional regulation. Recent evidence has shown that ubiquitin carboxy-terminal hydrolase-L1 (UCH-L1), a member of the deubiquitinating enzyme family that removes ubiquitin from protein substrates, is overexpressed in many types of cancer. This study thus examined the expression of UCH-L1 in human astrocytoma tissues. Formalin-fixed, paraffin-embedded astrocytoma samples were obtained from 40 patients, after which histopathological examination, typing, and grading were performed. The study group included 10 histologically normal brain tissues, which served as the control group, and 10 WHO grade II, 10 WHO grade III, and 10 WHO grade IV (glioblastoma) samples. Normal brain tissue samples were obtained from the histologically normal, non-tumoral portion of the pathology specimens. UCH-L1 expression was evaluated using quantitative reverse transcription-polymerase chain reaction and immunohistochemistry. Astrocytoma tissues exhibited higher UCH-L1 expression compared to the control group. UCH-L1 overexpression increased significantly together with the increase in astrocytoma grades (from II to IV). UCH-L1 could be a good diagnostic and therapeutic marker for determining astrocytoma development and progression.

The expression and clinical value of ubiquitin carboxyl-terminal hydrolase L1 in the blood of neonates with hypoxic ischemic encephalopathy.

BackgroundNeonatal hypoxic ischemic encephalopathy (HIE) can result in mental retardation due to the associated brain damage. Early identification of brain injury is vital for the prevention and treatment of brain damage in neonates. This study investigated the expression levels of serum ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) in neonates with HIE and its correlation with brain damage.MethodsFrom January 2019 to December 2020, 56 cases of neonatal patients with HIE were selected as the observation group, and 60 cases of healthy newborns delivered in our hospital during the same period were selected as the control group. Blood samples were obtained from neonates and the serum expression of UCH-L1 was detected by enzyme-linked immunosorbent assays (ELISAs). The relationship between UCH-L1 and neonatal prognosis and clinical features was analyzed.ResultsCompared with the healthy control group, the serum levels of UCH-L1 in the observation group was significantly higher (2.28±1.21 vs. 0.81±0.39 ng/mL, P=0.000). Furthermore, at 6 hours after birth, the serum levels of UCH-L1 were significantly higher in neonates with moderate to severe HIE compared to patients with mild HIE (2.92±0.80 and 1.76±0.72 ng/mL, respectively, P=0.000). Pearson correlation analysis showed that the expression levels of UCH-L1 were negatively correlated with the development quotient (DQ), intelligence index (MI), and the Neonatal Behavioral Neurological Assessment (NBNA) score of HIE newborns (P<0.05).ConclusionsThe level of UCH-L1 protein expression is elevated in the serum of newborns with HIE, and this may have a certain clinical value in predicting the intelligence of children.

Circulating glial fibrillary acidic protein and ubiquitin carboxy-terminal hydrolase-L1 as markers of neuronal damage in children with epileptic seizures.

Epilepsy is a common neurological disease that has a negative impact on physical, social, and cognitive function. Seizure-induced neuronal injury is one of the suggested mechanisms of epilepsy complications. We aimed to evaluate the circulating level of glial fibrillary acidic protein (GFAP) and ubiquitin carboxy-terminal hydrolase-L1 (UCH-L1) as markers of neuronal damage in children with epilepsy and its relation to epilepsy characteristics. METHODS: This case control study included 30 children with epilepsy and 30 healthy children as a control group. Seizure severity was determined based on Chalfont score. Serum level of GFAP and UCH-L1were measured, and their associations with epilepsy characteristics were investigated. Circulating levels of GFAP and UCH-L1 were significantly higher in children with epilepsy than in controls (17.440 ± 6.74 and 5.700 ± 1.64 vs 7.06 ± 3.30 and 1.81 ± 0.23, respectively) especially in those with generalized and active seizures. GFAP and UCH-L1 were significantly correlated to the severity of seizures in the previous 6months. Elevated GFAP level was a predictor for active seizures (OR 1.841, 95%CI 1.043-3.250, P = 0.035). Circulating GFAP and UCH-L1 expression is increased in children with epilepsy especially those with active seizures. GFAP and UCH-L 1may serve as peripheral biomarkers for neuronal damage in children with epilepsy that can be used to monitor disease progression and severity for early identification of those with drug-resistant epilepsy and those who are in need for epilepsy surgery.

Activation of hepatic stellate cells by the ubiquitin C-terminal hydrolase 1 protein secreted from hepatitis C virus-infected hepatocytes

Hepatitis C virus (HCV) infection of hepatocytes promotes liver fibrosis by activation of hepatic stellate cells (HSCs) and excessive deposition of extracellular matrix in liver tissue. Whether or not host factors released from the HCV-infected hepatocytes play role in HSCs activation is unclear. In this study, HSCs were activated by the conditioned medium derived from HCV replicon cells. Secretomic profiling of HCV replicon cells and the parental Huh7 cells revealed ubiquitin carboxy-terminal hydrolase L1 (UCHL1) as a novel secreted protein from HCV-infected hepatocytes. UCHL1 expression in hepatocytes was induced by HCV infection. UCHL1 was expressed in the liver and found in the plasma of patients with chronic hepatitis C. Molecular analysis by use of the anti-UCHL1 neutralization antibody and purified UCHL1 protein showed that secreted UCHL1 protein was bound to the cell surface of HSCs and activated JNK signaling leading to overexpression of alpha-smooth muscle actin and the activation of HSCs. These results provide further for understanding the underlying mechanism in HCV-mediated hepatic fibrogenesis.

Icariin reduces α-synuclein over-expression by promoting α-synuclein degradation.

The objectives of this study are to investigate the effects of icariin (a main component extracted from Epimedium) on over-expression of α-synuclein and to explore the underlying mechanisms. APPV717I transgenic (Tg) mice and A53T α-synuclein-transfected PC12 cells were used in this study. The content of α-synuclein mRNA was determined by reverse-transcription PCR (RT-PCR). Western blotting and immunohistochemistry were used to detect the protein expression of α-synuclein, parkin, ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), and heat shock protein 70 (HSP70). In 10-month-old APP Tg mice, α-synuclein expression was increased, and the expression of Parkin, UCH-L1, and HSP70 was decreased in the hippocampus. Intragastrical administration of icariin (30 and 100 μmol/kg) for 6 months (from 4 to 10 months old) decreased α-synuclein expression and increased the expression of Parkin, UCH-L1, and HSP70 in the hippocampus of APP Tg mice. Incubation of icariin (40 and 80 μM) with A53T α-synuclein-transfected PC12 cells for 24 h showed no difference in the expressions of α-synuclein mRNA among model group and icariin-treated groups, but decreased α-synuclein protein expression in both monomer and tetramer. Along with the downregulation of α-synuclein, icariin (40 and 80 μM) elevated the expression of Parkin, UCH-L1, and HSP70 in A53T α-synuclein-transfected cells. Icariin inhibited the over-expression of α-synuclein both in vivo and in vitro. The mechanism of icariin may be related to upregulate Parkin and UCH-L1 expression in ubiquitin-proteasome system and HSP70 in molecular chaperone, thus enhancing the degradation of α-synuclein. It is suggested that icariin may have the potential to treat Alzheimer's disease (AD) and other synucleinopathies.

NF-κB upregulates ubiquitin C-terminal hydrolase 1 in diseased podocytes in glomerulonephritis.

Podocyte injury is a pivotal factor during the progression of glomerular diseases. It has been demonstrated that the expression of ubiquitin carboxy-terminal hydrolase L1 (UCH-L1) is increased in injured podocytes in a number of types of glomerulonephritis. However, its mechanism of regulation remains to be elucidated. A previous study by our group suggested that UCH-L1 is a downstream protein of nuclear factor (NF)-κB signaling. In the present study, the involvement of NF-κB in the regulation of the expression of UCH-L1 was investigated in diseased podocytes in vivo and in vitro. Increases in the expression of phosphorylated NF-κB at p65 and UCH-L1 were detected using immunohistochemical analysis of kidney biopsy tissues from 56 cases of nephritis, including immunoglobulin A nephropathy, membranous glomerulonephritis and lupus nephritis. The two indicators were also analyzed using western blot analysis in cultured murine podocytes stimulated by inflammatory factors. The results of the present study demonstrated that in human renal biopsies of several cases of immune complex-mediated glomerulonephritis, the increases of NF-κB and UCH-L1 were positively correlated with the number of diseased podocytes. By contrast, in non-immune complex-mediated glomerulonephritis, no clear activation of NF-κB and increase of UCH-L1 expression was observed. In vitro, immune stimulation also led to the upregulation of UCH-L1 through the NF-κB signaling pathway in mouse podocytes. In conclusion, the results of the present study suggested that the activation of NF-κB and upregulation of UCH-L1 in podocytes may be vital in podocyte injury associated with immune complex-mediated glomerulonephritis.

MicroRNA-922 promotes tau phosphorylation by downregulating ubiquitin carboxy-terminal hydrolase L1 (UCHL1) expression in the pathogenesis of Alzheimer’s disease

Decreased levels of soluble ubiquitin carboxy-terminal hydrolase L1 (UCHL1) have been reported in the brains of sporadic Alzheimer’s disease (AD) patients, and the introduction of UCHL1 rescued the synaptic and cognitive function of AD model mice. Obviously, a reduction in the levels of UCHL1 may play a role in the pathogenesis of AD. However, the mechanisms underlying the regulation of UCHL1 levels in AD have not been fully elucidated. MicroRNAs (miRs) have been shown to participate in the process of AD. In our study, we discovered that microRNA-922 decreased the levels of UCHL1. Neurofibrillary tangles (NFTs) mainly consisting of the hyperphosphorylated microtubule-associated protein tau are the defining pathological features of AD. In the present study, we found the levels of UCHL1 affected the levels of phosphorylated tau: the phosphorylated tau levels increased after knockdown of UCHL1 expression, and the phosphorylated tau levels decreased when UCHL1 was overexpressed. Furthermore, overexpression of microRNA-922 increased the phosphorylated tau levels. In conclusion, miR-922 increasing the levels of phosphorylated tau by regulating UCHL1 levels contributed to the pathogenesis of AD. Our study partly explained one of the mechanisms underlying the downregulation of UCHL1 levels in AD patients and could enrich the content of tau pathology in the pathogenesis of AD.

Differential expression of ubiquitin carboxy-terminal hydrolase L1 in breast carcinoma and its biological significance

Ubiquitin carboxy-terminal hydrolase L1 (UCHL1) is a deubiquitinating enzyme that hydrolyzes ubiquitin. Previous reports have shown both tumorigenic and antitumorigenic roles for UCHL1. However, the expression patterns of UCHL1 protein, an area that is critical for validating its clinicopathologic roles among subtypes of breast cancer, is still lacking. Here we examined the expression of UCHL1 by immunohistochemistry in 243 breast carcinomas of various subtypes. We found expression of UCHL1 in 8.3% of invasive ductal carcinomas but not in other carcinoma subtypes, except for metaplastic carcinomas of the breast, which showed UCHL1 staining in 61.9% of cases, with the sarcomatous components being more intensely stained. UCHL1 expression in invasive ductal carcinomas significantly correlated with a high histologic grade (P = .001), the triple-negative phenotype (P = .02), and the basal-like phenotype (P <.001); furthermore, it was associated with poorer overall survival by univariate and multivariate analyses. Knockdown of UCHL1 in an invasive Snail variant-transfected MCF7 cells with high endogenous UCHL1 protein level significantly reduced invasion and anchorage-independent growth. Conclusively, our results demonstrate a role for UCHL1 in aggressive phenotypes in breast carcinoma. The high expression of UCHL1 in metaplastic carcinomas of the breast, which is pathogenically related to epithelial-mesenchymal transition, may implicate an association between UCHL1 expression and the epithelial-mesenchymal transition in breast cancer.

Sustained resistance to acute MPTP toxicity by hypothalamic dopamine neurons following chronic neurotoxicant exposure is associated with sustained up-regulation of parkin protein

Hypothalamic tuberoinfundibular dopamine (TIDA) neurons remain unaffected in Parkinson disease (PD) while there is significant degeneration of midbrain nigrostriatal dopamine (NSDA) neurons. A similar pattern of susceptibility is observed following acute exposure to the neurotoxicant 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and the resistance of TIDA neurons to MPTP is associated with increased expression of parkin and ubiquitin carboxy-terminal hydrolase L-1 (UCHL-1). In the present study, the response of TIDA and NSDA neurons to acute MPTP administration following chronic MPTP exposure was examined. Mice were treated with ten injections of either MPTP (20mg/kg; s.c.; every 3.5 days) or saline vehicle (10ml/kg; s.c.; every 3.5 days). Following a 21 day recovery period, chronic saline- and MPTP-treated mice received an additional injection of either saline (10ml/kg; s.c.) or MPTP (20mg/kg; s.c.) and were sacrificed 24h later. NSDA neurons displayed significant axon terminal degeneration (as reflected by decreases in DA, tyrosine hydroxylase (TH) and DA transporter concentrations in the striatum) as well as loss of TH-immunoreactive (IR) neurons in the substantia nigra (SN) following MPTP, whereas TIDA neurons revealed no overt axon terminal pathology or loss of TH-IR cell bodies. NSDA neuronal pathology was associated with transient decreases in concentrations of parkin and UCHL-1 protein in the SN, which returned to normal levels by 21 days following cessation of chronic neurotoxicant exposure. Resistance of TIDA neurons to MPTP toxicity was correlated with a transient increase in UCHL-1 and a sustained elevation in parkin in the arcuate nucleus. TIDA neurons represent a DA neuron population with a unique and inherent ability to adapt to acute and chronic toxicant administration with a sustained elevation of the neuroprotective protein parkin. The correlation between the ability to increase parkin and UCHL-1 expression and the resistance of DA neurons to neurotoxicant exposure is consistent with a functional link between these features and an underlying differential susceptibility to toxicant-associated neurodegeneration.

Ubiquitin carboxy-terminal hydrolase L1 may be involved in the development of mammary phyllodes tumors

Phyllodes tumors (PTs) are characterized by co-proliferation of the stroma and epithelium, with the stroma being the neoplastic element. Ubiquitin carboxy-terminal hydrolase L1 (UCHL1) is a deubiquitinating enzyme that was originally considered to be a neuronal-specific marker, but later reports have shown both tumorigenic and antitumorigenic roles for UCHL1. Although a role for UCHL1 has been explored in many cancers, a study on PTs has never been reported. We assessed UCHL1 expression in 49 cases of PTs and 16 fibroadenomas using immunohistochemistry and examined associations with clinicopathological features. In normal breast, strong staining for UCHL1 was consistently observed in the nerve bundles, if present, in breast stroma. Scattered stromal cells showed negative to weak staining. The ductal and lobular units, in contrast, showed no staining. In contrast to the 16 fibroadenomas, of which only 3 showed mild staining, UCHL1 expression was consistently observed in all 49 PTs. There was a significantly increasing trend of UCHL1 expression with increasing PT grade (P < 0.001); strong staining was observed in 24 % of benign PTs, but was present in 56 and 90 % of borderline and malignant PTs, respectively. Consistently, UCHL1 was focally positive in regions of benign to borderline malignancy, but strongly and diffusely immunoreactive in regions of malignancy in cases of malignant PTs. In addition to PT grade, UCHL1 expression correlated with increasing stromal atypia (P = 0.01), but not with other clinicopathological parameters. In conclusion, the consistent expression of UCHL1 in PTs and an increasing trend of UCHL1 expression with an increasing PT grade suggest a role for UCHL1 in the pathogenesis and malignant progression of PTs.

Recovery of hypothalamic tuberoinfundibular dopamine neurons from acute toxicant exposure is dependent upon protein synthesis and associated with an increase in parkin and ubiquitin carboxy-terminal hydrolase-L1 expression

Hypothalamic tuberoinfundibular dopamine (TIDA) neurons remain unaffected in Parkinson disease (PD) while there is significant degeneration of midbrain nigrostriatal dopamine (NSDA) neurons. A similar pattern of susceptibility is observed in acute and chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse and rotenone rat models of degeneration. It is not known if the resistance of TIDA neurons is a constitutive or induced cell-autonomous phenotype for this unique subset of DA neurons. In the present study, treatment with a single injection of MPTP (20mg/kg; s.c.) was employed to examine the response of TIDA versus NSDA neurons to acute injury. An acute single dose of MPTP caused an initial loss of DA from axon terminals of both TIDA and NSDA neurons, with recovery occurring solely in TIDA neurons by 16h post-treatment. Initial loss of DA from axon terminals was dependent on a functional dopamine transporter (DAT) in NSDA neurons but DAT-independent in TIDA neurons. The active metabolite of MPTP, 1-methyl, 4-phenylpyradinium (MPP+), reached higher concentration and was eliminated slower in TIDA compared to NSDA neurons, which indicates that impaired toxicant bioactivation or distribution is an unlikely explanation for the observed resistance of TIDA neurons to MPTP exposure. Inhibition of protein synthesis prevented TIDA neuron recovery, suggesting that the ability to recover from injury was dependent on an induced, rather than a constitutive cellular mechanism. Further, there were no changes in total tyrosine hydroxylase (TH) expression following MPTP, indicating that up-regulation of the rate-limiting enzyme in DA synthesis does not account for TIDA neuronal recovery. Differential candidate gene expression analysis revealed a time-dependent increase in parkin and ubiquitin carboxyl-terminal hydrolase-L1 (UCH-L1) expression (mRNA and protein) in TIDA neurons during recovery from injury. Parkin expression was also found to increase with incremental doses of MPTP. The increase in parkin expression occurred specifically within TIDA neurons, suggesting that these neurons have an intrinsic ability to up-regulate parkin in response to MPTP-induced injury. These data suggest that TIDA neurons have a compensatory mechanism to deal with toxicant exposure and increased oxidative stress, and this unique TIDA neuron phenotype provides a platform for dissecting the mechanisms involved in the natural resistance of central DA neurons following toxic insult.