WNK bodies cluster WNK4 and SPAK/OSR1 to promote NCC activation in hypokalemia.

K+ deficiency stimulates renal salt reuptake via the Na+-Cl- cotransporter (NCC) of the distal convoluted tubule (DCT), thereby reducing K+ losses in downstream nephron segments while increasing NaCl retention and blood pressure. NCC activation is mediated by a kinase cascade involving with no lysine (WNK) kinases upstream of Ste20-related proline-alanine-rich kinase (SPAK) and oxidative stress-responsive kinase-1 (OSR1). In K+ deficiency, WNKs and SPAK/OSR1 concentrate in spherical cytoplasmic domains in the DCT termed "WNK bodies," the significance of which is undetermined. By feeding diets of varying salt and K+ content to mice and using genetically engineered mouse lines, we aimed to clarify whether WNK bodies contribute to WNK-SPAK/OSR1-NCC signaling. Phosphorylated SPAK/OSR1 was present both at the apical membrane and in WNK bodies within 12 h of dietary K+ deprivation, and it was promptly suppressed by K+ loading. In WNK4-deficient mice, however, larger WNK bodies formed, containing unphosphorylated WNK1, SPAK, and OSR1. This suggests that WNK4 is the primary active WNK isoform in WNK bodies and catalyzes SPAK/OSR1 phosphorylation therein. We further examined mice carrying a kidney-specific deletion of the basolateral K+ channel-forming protein Kir4.1, which is required for the DCT to sense plasma K+ concentration. These mice displayed remnant mosaic expression of Kir4.1 in the DCT, and upon K+ deprivation, WNK bodies developed only in Kir4.1-expressing cells. We postulate a model of DCT function in which NCC activity is modulated by plasma K+ concentration via WNK4-SPAK/OSR1 interactions within WNK bodies.

Renal COP9 Signalosome Deficiency Alters CUL3-KLHL3-WNK Signaling Pathway.

BACKGROUND: The familial hyperkalemic hypertension (FHHt) cullin 3 (CUL3) mutant does not degrade WNK kinases normally, thereby leading to thiazide-sensitive Na-Cl cotransporter (NCC) activation. CUL3 mutant (CUL3Δ9) does not bind normally to the COP9 signalosome (CSN), a deneddylase involved in regulating cullin-RING ligases. CUL3Δ9 also caused increased degradation of the CUL3-WNK substrate adaptor kelch-like 3 (KLHL3). Here, we sought to determine how defective CSN action contributes to the CUL3Δ9 phenotype. METHODS: The Pax8/LC1 mouse system was used to generate mice in which the catalytically active CSN subunit, Jab1, was deleted only along the nephron, after full development (KS-Jab1-/-). RESULTS: Western blot analysis demonstrated that Jab1 deletion increased the abundance of neddylated CUL3. Moreover, total CUL3 expression was reduced, suggesting decreased CUL3 stability. KLHL3 was almost completely absent in KS-Jab1-/- mice. Conversely, the protein abundances of WNK1, WNK4, and SPAK kinases were substantially higher. Activation of WNK4, SPAK, and OSR1 was indicated by higher phosphorylated protein levels and translocation of the proteins into puncta, as observed by immunofluorescence. The ratio of phosphorylated NCC to total NCC was also higher. Surprisingly, NCC protein abundance was low, likely contributing to hypokalemia and Na+ and K+ wasting. Additionally, long-term Jab1 deletion resulted in kidney damage. CONCLUSIONS: Together, the results indicate that deficient CSN binding contributes importantly to the FHHt phenotype. Although defective CUL3Δ9-faciliated WNK4 degradation likely contributes, dominant effects on KLHL3 may be a second factor that is necessary for the phenotype.

Speed consensus control for a parallel six-wheel-legged robot on uneven terrain.

Wheel-legged robots suffer from the disturbances arising from the inconsistent of the wheel's speed and the external environments while driving over the uneven terrain, which may impair the smoothness of driving, or even fail in moving over the terrain. In this study, a speed consensus control (SCC) method that combines the distributed consensus algorithm (DCA) with the linear active disturbance rejection control (LADRC) is proposed to enhance the smoothness of the wheel-legged robot while traversing the uneven terrain. Firstly, the DCA is employed to reach a consensus amongst the speeds of the robot's body and each wheel which are regarded as a multi-agent system. Furthermore, the LADRC is applied to attenuate the disturbances arising from the model uncertainty and the unknown environments and to precisely track each wheel's desired speed obtained by the DCA. Finally, a series of simulations and experiments are conducted on a parallel six-wheel-legged robot (i.e., BIT-NAZAII) to validate the proposed method.

Control strategy of stable walking for a hexapod wheel-legged robot.

This paper provides a legged stable walking control strategy based on multi-sensor information feedback about BIT-NAZA-II, a large load parallel hexapod wheel-legged robot developing for the problem of vertical contact impact and horizontal sliding of heavy leg robot in complex terrain environments. The BIT-NAZA-II robot has six legs and six wheels, and the wheels are installed on the foot-end. The wheels of each foot-end for the legs of the robot are locked when walking with legs. In order to realize the smooth transition between swing phase and stance phase, the leg motion is divided into different stages for control by state machine switching controller based on event (SMSCE). In the Z-direction, in order to avoid the shaking of the body caused by the contact impact at the moment of contact between the foot-end and the ground during the walking of the robot, an active compliance controller (ACC) based on impedance control (IC) is applied to solve the problem of contact impact. Moreover, in the X-direction, the swing leg retraction (SLR) based on Bezier curve (BC) is introduced to generate the foot-end trajectory of the robot, which solves the slip problem of the heavy leg robot and improves the horizontal stability. Finally, the control strategy of stable walking is respectively verified by the simulations and experiments. The results show that the ACC based on IC can effectively reduce the contact impact between the foot-end and the ground in the Z-direction and improve the stability of body. Besides, the anti-sliding ability is realized after introducing SLR based on BC in the X-direction, and we also verify that stable walking control strategy is effective, which provides a reference value for the stable walking of heavy leg robot in complex terrain.

Healthy neonate born to a SARS-CoV-2 infected woman: A case report and review of literature.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a newly discovered coronavirus that has generated a worldwide outbreak of infections. Many people with coronavirus disease-2019 (COVID-19) have developed severe illness, and a significant number have died. However, little is known regarding infection by the novel virus in pregnant women. We herein present a case of COVID-19 confirmed in a woman delivering a neonate who was negative for SARS-CoV-2 and related it to a review of the literature on pregnant women and human coronavirus infections. CASE SUMMARY: The patient was a 36-year-old pregnant woman in her third trimester who had developed progressive clinical symptoms when she was confirmed as infected with SARS-CoV-2. Given the potential risks for both the pregnant woman and the fetus, an emergency cesarean section was performed, and the baby and his mother were separately quarantined and cared for. As a result, the baby currently shows no signs of SARS-CoV-2 infection (his lower respiratory tract samples were negative for the virus), while the mother completely recovered from COVID-19. CONCLUSION: Although we presented a single case, the successful result is of great significance for pregnant women with SARS-CoV-2 infection and with respect to fully understanding novel coronavirus pneumonia.

WNK4 limits distal calcium losses following acute furosemide treatment.

The distal nephron is essential for calcium homeostasis. This is evidenced by disordered calcium transport following disrupted distal nephron function occurring in salt-wasting tubulopathies or with diuretic use. A plethora of studies support a role for WNK4 in thick ascending limb (TAL) and distal convoluted tubule ion transport with most studies focusing on sodium transport. Little is known about the in vivo role of WNK4 in regulating calcium homeostsis. Here, we investigated the role of WNK4 in regulating distal nephron calcium transport using WNK4 knockout animals (WNK4-/- ). As has been shown previously, we found that baseline urinary calcium levels are normal following WNK4 deletion. Following acute treatment with the loop diuretic, furosemide, which causes hypercalciuria through TAL inhibition, WNK4-/- animals demonstrated increased calcium wasting compared with wild-type controls. WNK4-/- animals had decreased TRPV5 expression along DCT2 supporting a mechanistic role for this calcium channel in the increased calciuresis. As this supported the hypothesis that WNK4-/- animals have a tendency toward calcium wasting under stress, we tested the effects of a calcium-deplete diet on urinary calcium excretion. Urinary calcium excretion and plasma ionized calcium levels were not different between control and knockout animals following consumption of a calcium-deplete diet. Our data show that WNK4, via regulation of TRPV5, limits distal calcium losses following acute treatment with furosemide; however, WNK4 deletion does not affect the chronic renal response to dietary calcium depletion. Our data reveal an in vivo role for WNK4 in distal nephron calcium handling that is important for fine-tuning calcium reabsorption.

Toxicities of different first-line chemotherapy regimens in the treatment of advanced ovarian cancer: A network meta-analysis.

BACKGROUND: Ovarian cancer (OC) is the 5th leading cause of cancer-related deaths around the world, and several chemotherapy regimens have been applied in the treatment of OC. We aim to compare toxicities of different chemotherapy regimens in the treatment of advanced ovarian cancer (AOC) using network meta-analysis. METHODS: Literature research in Cochrane Library, PubMed, and EMBASE was performed up to November 2015. Eligible randomized controlled trials (RCTs) of different chemotherapy regimens were included. Network meta-analysis combined direct and indirect evidence to assess pooled odds ratios (ORs) and draw the surface under the cumulative ranking (SUCRA) curves. RESULTS: Thirteen eligible RCTs were included in this network meta-analysis, including 8 chemotherapy regimens (paclitaxel + carboplatin [PC], pegylated liposomal doxorubicin [PLD] + carboplatin, carboplatin, gemcitabine + carboplatin, paclitaxel, PC + epirubicin, PC + topotecan, docetaxel + carboplatin). Gemcitabine + carboplatin regimen exerted higher incidence of anemia when compared with carboplatin and paclitaxel regimens. The incidence of febrile neutropenia of gemcitabine + carboplatin regimen was higher than that of PC, PLD + carboplatin, carboplatin, and PC + topotecan regimens. Topotecan PC + epirubicin regimen had a higher toxicity, comparing with PC, PLD + carboplatin, and PC + topotecan regimens. As for thrombocytopenia, gemcitabine + carboplatin chemotherapy regimen produced an obviously higher toxicity than PC and carboplatin. As for nausea, PLD + carboplatin chemotherapy regimen had a significantly higher toxicity than that of carboplatin chemotherapy regimen. Moreover, when compared with PC and carboplatin chemotherapy regimens, the toxicity of PC + epirubicin was greatly higher to patients with AOC. CONCLUSION: The nonhematologic toxicity of PLD + carboplatin regimen was higher than other regimens, which was clinically significant for the treatment of AOC.

Expressions of lysophosphatidic acid receptors in the development of human ovarian carcinoma.

AIM: To investigate the associations between the expressions of three lysophosphatidic acid (LPA) receptors (LPA1-3) and the development of ovarian carcinoma (OC). METHOD: Ovarian tissue specimens, including normal ovarian epithelium tissues, benign ovarian tumor tissues and OC tissues were collected from patients who underwent surgical resections between March 2012 and December 2014. Immunohistochemical staining was used to detect LPA receptor expressions in ovarian tissues. Reverse transcription-polymerase chain reaction and Western blotting were used to detect mRNA and protein expression of LPA receptors, respectively. Association analysis between LPA receptors protein expression and clinical pathological characteristics was conducted. The value of LPA2 and LPA3 in discriminating OC was confirmed by receiver-operator characteristic (ROC) curves analysis. RESULTS: The positive expression rates of LPA2 and LPA3 in OC group was obviously higher than normal control and benign groups. The LPA2 and LPA3 mRNA and protein levels in OC group were higher than in normal control and benign groups. LPA2 and LPA3 mRNA expression levels were positively correlated with LPA2 and LPA3 protein expression in OC group. ROC curve analysis revealed that LPA2 yield a specificity of 96.3% and a sensitivity of 97.9%, and LPA3 yield a specificity of 98.5% and a sensitivity of 97.9% for the detection of OC. CONCLUSION: LPA2 and LPA3 were highly expressed in OC tissues, which may be involved in the development of OC. Further, LPA2 and LPA3 had higher sensitivity and specificity in distinguishing the OC from benign ovarian tumors, which could be potential diagnostic indictors in OC.

Role of RASSF1A promoter methylation in the pathogenesis of ovarian cancer: a meta-analysis.

OBJECTIVE: The aim of the current meta-analysis was to comprehensively assess the role of RASSF1A promoter methylation in the pathogenesis of ovarian cancer. METHOD: A range of electronic databases were searched: Web of Science (1945-2013), the Cochrane Library Database (Issue 12, 2013), PubMed (1966-2013), EMBASE (1980-2013), CINAHL (1982-2013), and the Chinese Biomedical Database (1982-2013) without language restrictions. Meta-analysis was conducted using the STATA 12.0 software. The crude odds ratio (OR) with its corresponding 95% confidence interval (CI) was calculated. RESULTS: Twelve clinical cohort studies with a total of 739 ovarian cancer patients were included in the current meta-analysis. The results of our meta-analysis suggested that the frequency of RASSF1A promoter methylation in cancer tissues was higher compared with benign, adjacent, and normal tissues (cancer tissues vs. benign tissues: OR=9.92, 95% CI: 7.67-12.82, p<0.001; cancer tissues vs. adjacent tissues: OR=68.15, 95% CI: 39.30-118.18, p<0.001; cancer tissues vs. normal tissues: OR=30.71, 95% CI: 23.12-40.80, p<0.001; respectively). Subgroup analysis based on ethnicity and sample types revealed that RASSF1A gene methylation was closely associated with the pathogenesis of ovarian cancer in all subgroups (all p<0.05). CONCLUSION: Our findings indicated that abnormal RASSF1A promoter methylation may be strongly correlated with the pathogenesis of ovarian cancer.