Regulation of PKD2 channel function by TACAN.

Autosomal dominant polycystic kidney disease is caused by mutations in the membrane receptor PKD1 or the cation channel PKD2. TACAN (also termed TMEM120A), recently reported as an ion channel in neurons for mechanosensing and pain sensing, is also distributed in diverse non-neuronal tissues, such as kidney, heart and intestine, suggesting its involvement in other functions. In this study, we found that TACAN is in a complex with PKD2 in native renal cell lines. Using the two-electrode voltage clamp in Xenopus oocytes, we found that TACAN inhibits the channel activity of PKD2 gain-of-function mutant F604P. TACAN fragments containing the first and last transmembrane domains interacted with the PKD2 C- and N-terminal fragments, respectively. The TACAN N-terminus acted as a blocking peptide, and TACAN inhibited the function of PKD2 by the binding of PKD2 with TACAN. By patch clamping in mammalian cells, we found that TACAN inhibits both the single-channel conductance and the open probability of PKD2 and mutant F604P. PKD2 co-expressed with TACAN, but not PKD2 alone, exhibited pressure sensitivity. Furthermore, we found that TACAN aggravates PKD2-dependent tail curvature and pronephric cysts in larval zebrafish. In summary, this study revealed that TACAN acts as a PKD2 inhibitor and mediates mechanosensitivity of the PKD2-TACAN channel complex. KEY POINTS: TACAN inhibits the function of PKD2 in vitro and in vivo. TACAN N-terminal S1-containing fragment T160X interacts with the PKD2 C-terminal fragment N580-L700, and its C-terminal S6-containing fragment L296-D343 interacts with the PKD2 N-terminal A594X. TACAN inhibits the function of the PKD2 channel by physical interaction. The complex of PKD2 with TACAN, but not PKD2 alone, confers mechanosensitivity.

Comparison of efficacy and safety of robotic surgery and laparoscopic surgery for choledochal cyst in children: a systematic review and proportional meta-analysis.

BACKGROUND: Most commonly, cyst excision and Roux-en-Y hepaticojejunostomy reconstruction are the optimal treatment for choledochal cysts (CC). Robotic surgery (RS) is being conducted with increasing frequency to treat CC. It is unclear whether RS can overcome the limitations of laparoscopic surgery (LS) and improve the prognosis of patients. In terms of efficacy, evidence concerning which minimally invasive surgery is preferred is, however, sparse. Our objective is to further compare the efficacy of RS and LS in children with CC and draw a useful clinical conclusion. METHODS: Studies meeting inclusion criteria were identified from a series of databases, consisting of PubMed, Embase, Scopus, Web of Science, the Cochrane Library and their reference list of articles up to May 2022. Eligible articles comprised at least five objects that were younger than 18 years of age and the language was limited to English. Two authors independently evaluated selected studies and extracted data for analysis. RESULTS: Forty studies were selected for analysis, with thirty-six reporting data on LS and eight containing data on RS. The pooled conversion rate and pooled postoperative complication rate of RS were lower than those of LS, but none of them was statistically significant. Moreover, comparisons of the following detailed postoperative complication rates were not statistically significant, such as intestinal obstruction or ileus, anastomotic bleeding, anastomotic or bile leakage, and anastomotic stenosis. However, the intraoperative blood loss and the postoperative hospital stay in RS group were significantly lower than those in LS group. CONCLUSIONS: RS is a safe and feasible option for children with CC. Further studies with more cases, long-term efficacy and health economics analysis are needed to confirm whether RS is more advantageous.

Robotic-assisted choledochal cyst excision with Roux-en-Y hepaticojejunostomy in children: does age matter?

BACKGROUND: Robotic-assisted surgery (RAS) is being increasingly used in pediatric choledochal cysts (CCs), but is most commonly performed in older children and adolescents. The outcomes in young infants remain to be explored. The purpose of this study is to compare outcomes in infants aged ≤ 1 year with an older cohort. METHODS: From July 2015 to January 2020, a retrospective study was conducted to evaluate the RAS in patients with CCs at our institution. Patients were divided into two groups (group A ≤ 1 year old and group B > 1 year old). Demographics, intraoperative details, complications, and outcomes were analyzed. RESULTS: A total of 79 patients were included in the study (28 patients in group A and 51patients in group B). The median age of patients at the surgery in group A was 4.9 months (IQR: 3.1-9.1), compared with 46.8 months (IQR: 28.5-86.5) in group B. Three patients in group A were neonates. No conversion to open surgery was required. No significant differences were found between the two groups including sex, Todani type, or diameter of the cysts. The diameter of the common hepatic duct was smaller in group A (6.0 ± 1.7 vs. 9.0 ± 3.0 mm; p < 0.001). Group A had the longer hepaticojejunostomy time [51(44-58) vs. 42(38-53) min; p = 0.013], while Group B had the longer cyst excision time [43(41-59) vs. 50(43-60) min; p = 0.005]. However, their total operative time and console time were similar. There were no statistical differences in length of hospital stay and complications between the two groups. CONCLUSIONS: Robot-assisted cyst resection and hepaticojejunostomy are feasible and safe in infants ≤ 1 year old. Age cannot be considered an absolute contraindication for robotic surgery in patients with CCs.

Laparoscopic lateral duodenojejunostomy for pediatric superior mesenteric artery compression syndrome: a cohort retrospective study.

PURPOSE: There are only a few case reports of laparoscopic lateral duodenojejunostomy (LLDJ) in children with Wilkie's syndrome, also known as superior mesenteric artery compression syndrome (SMAS). We aimed to describe our laparoscopic technique and evaluate its outcomes for SMAS in children. METHODS: From January 2013 to May 2021, SMAS children who received LLDJ were included. The procedure was carried out utilizing the four-trocar technique. The elevation of the transverse colon allows good exposure of the dilated and bulging second and third sections of the duodenum. Using a linear stapler, we established a lateral anastomosis connecting the proximal jejunum with the third part of the duodenum. Following that, a running suture was used to intracorporeally close the common enterotomy. Clinical data on patients was collected for analysis. The demographics, diagnostic findings, and postoperative outcomes were analyzed retrospectively. RESULTS: We retrospectively analyzed 9 SMAS patients (6 females and 3 males) who underwent LLDJ, aged between 7 and 17 years old. The mean operative time was 118.4 ± 16.5 min and the mean estimated blood loss was 5.6 ± 1.4 ml. There were no conversion, intraoperative complications or immediate postoperative complications. The mean postoperative hospital stay was 6.8 ± 1.9 days and the mean follow-up time was 5.4 ± 3.0 years. During follow-up, seven patients (77.8%) experienced complete recovery of symptoms prior to surgery. One patient (11.1%) still had mild vomiting, which resolved with medication. Another patient (11.1%) developed psychological-induced nausea, which significantly improved after treatment with education, training and diet management. CONCLUSIONS: LLDJ represents a feasible and safe treatment option for SMAS in well-selected children. Further evaluation with more cases and case-control studies is required for the real benefits.

Full-Chain FeCl3 Catalyzation Is Sufficient to Boost Cellulase Secretion and Cellulosic Ethanol along with Valorized Supercapacitor and Biosorbent Using Desirable Corn Stalk.

Cellulosic ethanol is regarded as a perfect additive for petrol fuels for global carbon neutralization. As bioethanol conversion requires strong biomass pretreatment and overpriced enzymatic hydrolysis, it is increasingly considered in the exploration of biomass processes with fewer chemicals for cost-effective biofuels and value-added bioproducts. In this study, we performed optimal liquid-hot-water pretreatment (190 °C for 10 min) co-supplied with 4% FeCl3 to achieve the near-complete biomass enzymatic saccharification of desirable corn stalk for high bioethanol production, and all the enzyme-undigestible lignocellulose residues were then examined as active biosorbents for high Cd adsorption. Furthermore, by incubating Trichoderma reesei with the desired corn stalk co-supplied with 0.05% FeCl3 for the secretion of lignocellulose-degradation enzymes in vivo, we examined five secreted enzyme activities elevated by 1.3-3.0-fold in vitro, compared to the control without FeCl3 supplementation. After further supplying 1:2 (w/w) FeCl3 into the T. reesei-undigested lignocellulose residue for the thermal-carbonization process, we generated highly porous carbon with specific electroconductivity raised by 3-12-fold for the supercapacitor. Therefore, this work demonstrates that FeCl3 can act as a universal catalyst for the full-chain enhancement of biological, biochemical, and chemical conversions of lignocellulose substrates, providing a green-like strategy for low-cost biofuels and high-value bioproducts.

Expression and Development of TARP γ-4 in Embryonic Zebrafish.

Fast excitatory synaptic transmission in the CNS is mediated by the neurotransmitter glutamate, binding to and activating AMPA receptors (AMPARs). AMPARs are known to interact with auxiliary proteins that modulate their behavior. One such family of proteins is the transmembrane AMPAR-related proteins, known as TARPs. Little is known about the role of TARPs during development or about their function in nonmammalian organisms. Here, we report on the presence of TARP γ-4 in developing zebrafish. We find that zebrafish express 2 forms of TARP γ-4: γ-4a and γ-4b as early as 12 h post-fertilization. Sequence analysis shows that both γ-4a and γ-4b shows great level of variation particularly in the intracellular C-terminal domain compared to rat, mouse, and human γ-4. RT-qPCR showed a gradual increase in the expression of γ-4a throughout the first 5 days of development, whereas γ-4b levels were constant until day 5 when levels increased significantly. Knockdown of TARP γ-4a and γ-4b via either splice-blocking morpholinos or translation-blocking morpholinos resulted in embryos that exhibited deficits in C-start escape responses, showing reduced C-bend angles. Morphant larvae displayed reduced bouts of swimming. Whole-cell patch-clamp recordings of AMPAR-mediated currents from Mauthner cells showed a reduction in the frequency of mEPCs but no change in amplitude or kinetics. Together, these results suggest that γ-4a and γ-4b are required for proper neuronal development.

TRIM4 interacts with TRPM8 and regulates its channel function through K423-mediated ubiquitination.

Transient receptor potential melastatin member 8 (TRPM8), a Ca2+ -permeable nonselective cation channel activated by cold and cooling agents, mediates allodynia. Dysfunction or abnormal expression of TRPM8 has been found in several human cancers. The role of ubiquitination in the regulation of TRPM8 function remains poorly understood. Here, we identified the ubiquitin (Ub)-ligase E3, tripartite motif-containing 4 (TRIM4), as a novel interaction partner of TRPM8 and confirmed that the TRIM4-TRPM8 interaction was mediated through the SPRY domain of TRIM4. Patch-clamp assays showed that TRIM4 negatively regulates TRPM8-mediated currents in HEK293 cells. Moreover, TRIM4 reduced the expression of TRPM8 on the cell surface by promoting the K63-linked ubiquitination of TRPM8. Further analyses revealed that the TRPM8 N-terminal lysine residue at 423 was the major ubiquitination site that mediates its functional regulation by TRIM4. A Ub-activating enzyme E1, Ub-like modifier-activating enzyme 1 (UBA1), was also found to interact with TRPM8, thereby regulating its channel function and ubiquitination. In addition, knockdown of UBA1 impaired the regulation of TRPM8 ubiquitination and function by TRIM4. Thus, this study demonstrates that TRIM4 downregulates TRPM8 via K423-mediated TRPM8 ubiquitination and requires UBA1 to regulate TRPM8.

The Fabp5/calnexin complex is a prerequisite for sensitization of mice to experimental autoimmune encephalomyelitis.

We previously showed that calnexin (Canx)-deficient mice are desensitized to experimental autoimmune encephalomyelitis (EAE) induction, a model that is frequently used to study inflammatory demyelinating diseases, due to increased resistance of the blood-brain barrier to immune cell transmigration. We also discovered that Fabp5, an abundant cytoplasmic lipid-binding protein found in brain endothelial cells, makes protein-protein contact with the cytoplasmic C-tail domain of Canx. Remarkably, both Canx-deficient and Fabp5-deficient mice commonly manifest resistance to EAE induction. Here, we evaluated the importance of Fabp5/Canx interactions on EAE pathogenesis and on the patency of a model blood-brain barrier to T-cell transcellular migration. The results demonstrate that formation of a complex comprised of Fabp5 and the C-tail domain of Canx dictates the permeability of the model blood-brain barrier to immune cells and is also a prerequisite for EAE pathogenesis.

LncRNA PVT1 promotes gemcitabine resistance of pancreatic cancer via activating Wnt/ß-catenin and autophagy pathway through modulating the miR-619-5p/Pygo2 and miR-619-5p/ATG14 axes.

BACKGROUND: Pancreatic cancer is one of the most lethal malignancies and has an extremely poor diagnosis and prognosis. The development of resistance to gemcitabine is still a major challenge. The long noncoding RNA PVT1 was reported to be involved in carcinogenesis and chemoresistance; however, the mechanism by which PVT1 regulates the sensitivity of pancreatic cancer to gemcitabine remains poorly understood. METHODS: The viability of pancreatic cancer cells was assessed by MTT assay in vitro and xenograft tumor formation assay in vivo. The expression levels of PVT1 and miR-619-5p were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Western blotting analysis and qRT-PCR were performed to assess the protein and mRNA levels of Pygo2 and ATG14, respectively. Autophagy was explored via autophagic flux detection under confocal microscopy and autophagic vacuole investigation under transmission electron microscopy (TEM). The functional role and mechanism of PVT1 were further investigated by gain- and loss-of-function assays in vitro. RESULTS: In the present study, we demonstrated that PVT1 was up-regulated in gemcitabine-resistant pancreatic cancer cell lines. Gain- and loss-of-function assays revealed that PVT1 impaired sensitivity to gemcitabine in vitro and in vivo. We further found that PVT1 up-regulated the expression of both Pygo2 and ATG14 and thus regulated Wnt/ß-catenin signaling and autophagic activity to overcome gemcitabine resistance through sponging miR-619-5p. Moreover, we discovered three TCF/LEF binding elements (TBEs) in the promoter region of PVT1, and activation of Wnt/ß-catenin signaling mediated by the up-regulation of Pygo2 increased PVT1 expression by direct binding to the TBE region. Furthermore, PVT1 was discovered to interact with ATG14, thus promoting assembly of the autophagy specific complex I (PtdIns3K-C1) and ATG14-dependent class III PtdIns3K activity. CONCLUSIONS: These data indicate that PVT1 plays a critical role in the sensitivity of pancreatic cancer to gemcitabine and highlight its potential as a valuable target for pancreatic cancer therapy.

Two pools of IRE1α in cardiac and skeletal muscle cells.

The endoplasmic reticulum (ER) plays a central role in cellular stress responses via mobilization of ER stress coping responses, such as the unfolded protein response (UPR). The inositol-requiring 1α (IRE1α) is an ER stress sensor and component of the UPR. Muscle cells also have a well-developed and highly subspecialized membrane network of smooth ER called the sarcoplasmic reticulum (SR) surrounding myofibrils and specialized for Ca2+ storage, release, and uptake to control muscle excitation-contraction coupling. Here, we describe 2 distinct pools of IRE1α in cardiac and skeletal muscle cells, one localized at the perinuclear ER and the other at the junctional SR. We discovered that, at the junctional SR, calsequestrin binds to the ER luminal domain of IRE1α, inhibiting its dimerization. This novel interaction of IRE1α with calsequestrin, one of the highly abundant Ca2+ handling proteins at the junctional SR, provides new insights into the regulation of stress coping responses in muscle cells.-Wang, Q., Groenendyk, J., Paskevicius, T., Qin, W., Kor, K. C., Liu, Y., Hiess, F., Knollmann, B. C., Chen, S. R. W., Tang, J., Chen, X.-Z., Agellon, L. B., Michalak, M. Two pools of IRE1α in cardiac and skeletal muscle cells.