bims-bicyki Biomed News
on Bicaudal-C1 and interactors in cystic kidney disease
Issue of 2021‒06‒27
23 papers selected by
Céline Gagnieux
École Polytechnique Fédérale de Lausanne (EPFL)

  1. J Am Soc Nephrol. 2021 Jun 21. pii: ASN.2020071094. [Epub ahead of print]
      Background: In autosomal dominant polycystic kidney disease (ADPKD), cyst development and enlargement lead to end-stage kidney disease. Macrophage recruitment and interstitial inflammation have been shown to promote cyst growth. TWEAK is a TNF superfamily (TNFSF) cytokine that regulates inflammatory responses, cell proliferation and cell death, and its receptor Fn14 (TNFRSF12a) is expressed in macrophage and nephron epithelia. Methods: In order to evaluate the role of the TWEAK signaling pathway in cystic disease, we evaluated Fn14 expression in human and in an orthologous murine model of ADPKD. We also explored the cystic response to TWEAK signaling pathway activation and inhibition by peritoneal injection. Results: Meta-analysis of published animal models data of cystic disease reveals mRNA upregulation of several components of the TWEAK signaling pathway. We also observed that TWEAK and Fn14 were overexpressed in mouse ADPKD kidney cysts, while TWEAK was significantly high in urine and cystic fluid from ADPKD patients. TWEAK administration induced cystogenesis and increased cystic growth, worsening the phenotype in a murine ADPKD model. Anti-TWEAK antibodies significantly slowed the progression of ADPKD, preserved renal function, and improved survival. Furthermore, the anti-TWEAK cystogenesis reduction is related to decreased cell proliferation-MAPK signaling, decreased NF-κB pathway activation, slight reduction of fibrosis and apoptosis, and an indirect decrease of macrophage recruitment. Conclusions: This study identifies the TWEAK signaling pathway as a new disease mechanism involved in cystogenesis and cystic growth and may lead to a new therapeutic approach in ADPKD.
  2. Kidney Int Rep. 2021 Jun;6(6): 1687-1698
      Introduction: Autosomal dominant polycystic kidney disease (ADPKD) causes kidney failure typically in adulthood, but the disease starts in utero. Copeptin, epidermal growth factor (EGF), and monocyte chemoattractant protein-1 (MCP-1) are associated with severity and hold prognostic value in adults but remain unstudied in the early disease stage. Kidneys from adults with ADPKD exhibit macrophage infiltration, and a prominent role of MCP-1 secretion by tubular epithelial cells is suggested from rodent models.Methods: In a cross-sectional study, plasma copeptin, urinary EGF, and urinary MCP-1 were evaluated in a pediatric ADPKD cohort and compared with age-, sex-, and body mass index (BMI)-matched healthy controls. MCP-1 was studied in mouse collecting duct cells, human proximal tubular cells, and fetal kidney tissue.
    Results: Fifty-three genotyped ADPKD patients and 53 controls were included. The mean (SD) age was 10.4 (5.9) versus 10.5 (6.1) years (P = 0.543), and the estimated glomerular filtration rate (eGFR) was 122.7 (39.8) versus 114.5 (23.1) ml/min per 1.73 m2 (P = 0.177) in patients versus controls, respectively. Plasma copeptin and EGF secretion were comparable between groups. The median (interquartile range) urinary MCP-1 (pg/mg creatinine) was significantly higher in ADPKD patients (185.4 [213.8]) compared with controls (154.7 [98.0], P = 0.010). Human proximal tubular cells with a heterozygous PKD1 mutation and mouse collecting duct cells with a PKD1 knockout exhibited increased MCP-1 secretion. Human fetal ADPKD kidneys displayed prominent MCP-1 immunoreactivity and M2 macrophage infiltration.
    Conclusion: An increase in tubular MCP-1 secretion is an early event in ADPKD. MCP-1 is an early disease severity marker and a potential treatment target.
    Keywords:  ADPKD; chemokine; distal tubule; inflammation; pediatric nephrology; proximal tubule
  3. BMC Gastroenterol. 2021 Jun 24. 21(1): 267
      BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is the most frequent genetic kidney disease and polycystic liver disease is its major extrarenal manifestation, however biliary peritonitis due to a liver cyst rupture is extremely rare.CASE PRESENTATION: The patient was a 71-year-old Japanese woman who was diagnosed with ADPKD 3 years previously and developed right abdominal pain suddenly 1 month previously. As abdominal computed tomography (CT) showed a ruptured liver cyst in the right lobe, she was admitted to our hospital. Her symptoms improved with conservative management and she was discharged from the hospital after 1 week. Although she was asymptomatic for a while, she noticed abdominal distension and general malaise at 1 month after hospital discharge. Since abdominal CT showed massive ascites, she was admitted to our hospital again. A physical examination revealed abdominal distention without tenderness. Her serum creatinine, alkaline phosphatase, γ-glutamyl transpeptidase, total bilirubin, and CA19-9 were elevated. Abdominal paracentesis revealed amber transparent ascites and the bilirubin and CA19-9 concentrations were high. She was diagnosed with biliary peritonitis due to a ruptured liver cyst. Hemodialysis treatment was initiated with drainage of the ascites. The outflow of the ascites was no tendency to decrease and drip infusion cholangiography (DIC)-CT revealed a communication between the ruptured cyst and an intrahepatic bile duct. On day 31, she was transferred to a university hospital and abdominal surgery was performed. After removing the necrotic roof of the ruptured cyst on the right liver lobe, the orifice of the bile leakage was sutured. Cholecystectomy was performed and cholangiography showed no stones in the common bile duct. Abdominal CT one month after the operation showed no recurrence of ascites and she was discharged on day 49. Hemodialysis treatment was discontinued immediately after discharge because urine volume increased and her creatinine level decreased. There has been no recurrence of ascites since then.
    CONCLUSIONS: While rare, biliary peritonitis can occur in association with the rupture of a liver cyst in ADPKD patients due to communication between the cyst and the intrahepatic bile duct, and DIC-CT should be recommended when biliary cyst rupture is suspected.
    Keywords:  Autosomal dominant polycystic kidney disease; Biliary peritonitis; Liver cyst rupture
  4. Biochem Soc Trans. 2021 Jun 22. pii: BST20200757. [Epub ahead of print]
      Polycystic Kidney Disease (PKD) refers to a group of disorders, driven by the formation of cysts in renal tubular cells and is currently one of the leading causes of end-stage renal disease. The range of symptoms observed in PKD is due to mutations in cilia-localising genes, resulting in changes in cellular signalling. As such, compounds that are currently in preclinical and clinical trials target some of these signalling pathways that are dysregulated in PKD. In this review, we highlight these pathways including cAMP, EGF and AMPK signalling and drugs that target them and may show promise in lessening the disease burden of PKD patients. At present, tolvaptan is the only approved therapy for ADPKD, however, it carries several adverse side effects whilst comparatively, no pharmacological drug is approved for ARPKD treatment. Aside from this, drugs that have been the subject of multiple clinical trials such as metformin, which targets AMPK signalling and somatostatins, which target cAMP signalling have shown great promise in reducing cyst formation and cellular proliferation. This review also discusses other potential and novel targets that can be used for future interventions, such as β-catenin and TAZ, where research has shown that a reduction in the overexpression of these signalling components results in amelioration of disease phenotype. Thus, it becomes apparent that well-designed preclinical investigations and future clinical trials into these pathways and other potential signalling targets are crucial in bettering disease prognosis for PKD patients and could lead to personalised therapy approaches.
    Keywords:  Polycystin-1; Polycystin-2; fibrocystin; polycystic kidney disease; signalling
  5. J Am Soc Nephrol. 2021 Jun 23. pii: ASN.2021010101. [Epub ahead of print]
      Background Genome-wide mapping of transcription factor (TF) binding sites is essential to identify a TF's direct target genes in kidney development and diseases. However, due to the cellular complexity of the kidney and limited numbers of a given cell type, it has been challenging to determine the binding sites of a TF in vivo. cAMP-response element-binding protein (CREB) is phosphorylated and hyperactive in autosomal dominant polycystic kidney disease (ADPKD). We focus on CREB as an example to profile genomic loci bound by a TF and to identify its target genes using low numbers of specific kidney cells. Methods Cleavage under targets and release using nuclease (CUT&RUN) assays were performed with Dolichos biflorus agglutinin (DBA)-positive tubular epithelial cells from normal and ADPKD mouse kidneys. Pharmacological inhibition of CREB with 666-15 and genetic inhibition with A-CREB were undertaken using ADPKD mouse models. Results CUT&RUN to profile genome-wide distribution of phosphorylated CREB (p-CREB) indicated correlation of p-CREB binding with active histone modifications (H3K4me3 and H3K27ac) in cystic epithelial cells. Integrative analysis with CUT&RUN and RNA-sequencing revealed CREB direct targets, including genes involved in ribosome biogenesis and protein synthesis. Pharmacological and genetic inhibition of CREB suppressed cyst growth in ADPKD mouse models. Conclusions CREB promotes cystogenesis by activating ribosome biogenesis genes. CUT&RUN, coupled with transcriptomic analysis, enables interrogation of TF binding and identification of direct TF targets from a low number of specific kidney cells.
  6. J Cell Mol Med. 2021 Jun 25.
      The alteration of the mucociliary clearance is a major hallmark of respiratory diseases related to structural and functional cilia abnormalities such as chronic obstructive pulmonary diseases (COPD), asthma and cystic fibrosis. Primary cilia and motile cilia are the two principal organelles involved in the control of cell fate in the airways. We tested the effect of primary cilia removal in the establishment of a fully differentiated respiratory epithelium. Epithelial barrier integrity was not altered while multiciliated cells were decreased and mucous-secreting cells were increased. Primary cilia homeostasis is therefore paramount for airway epithelial cell differentiation. Primary cilia-associated pathophysiologic implications require further investigations in the context of respiratory diseases.
    Keywords:  airway epithelium; cell differentiation; cilia
  7. Sci Adv. 2021 Jun;pii: eabe3401. [Epub ahead of print]7(26):
      Mutation of ciliopathy protein HYLS1 causes the perinatal lethal hydrolethalus syndrome (HLS), yet the underlying molecular etiology and pathogenesis remain elusive. Here, we reveal unexpected mechanistic insights into the role of mammalian HYLS1 in regulating primary cilia. HYLS1 is recruited to the ciliary base via a direct interaction with the type Iγ phosphatidylinositol 4-phosphate [PI(4)P] 5-kinase (PIPKIγ). HYLS1 activates PIPKIγ by interrupting the autoinhibitory dimerization of PIPKIγ, which thereby expedites depletion of centrosomal PI(4)P to allow axoneme nucleation. HYLS1 deficiency interrupts the assembly of ciliary NPHP module and agonist-induced ciliary exit of β-arrestin, which, in turn, disturbs the removal of ciliary Gpr161 and activation of hedgehog (Hh) signaling. Consistent with this model of pathogenesis, the HLS mutant HYLS1D211G supports ciliogenesis but not activation of Hh signaling. These results implicate mammalian HYLS1 as a multitasking protein that facilitates ciliogenesis and ciliary signaling by coordinating with the ciliary lipid kinase PIPKIγ.
  8. J Cell Biol. 2021 Sep 06. pii: e202010177. [Epub ahead of print]220(9):
      The Hedgehog pathway, critical to vertebrate development, is organized in primary cilia. Activation of signaling causes the Hedgehog receptor Ptch1 to exit cilia, allowing a second receptor, Smo, to accumulate in cilia and activate the downstream steps of the pathway. Mechanisms regulating the dynamics of these receptors are unknown, but the ubiquitination of Smo regulates its interaction with the intraflagellar transport system to control ciliary levels. A focused screen of ubiquitin-related genes identified nine required for maintaining low ciliary Smo at the basal state. These included cytoplasmic E3s (Arih2, Mgrn1, and Maea), a ciliary localized E3 (Wwp1), a ciliary localized E2 (Ube2l3), a deubiquitinase (Bap1), and three adaptors (Kctd5, Skp1a, and Skp2). The ciliary E3, Wwp1, binds Ptch1 and localizes to cilia at the basal state. Activation of signaling removes both Ptch1 and Wwp1 from cilia, thus providing an elegant mechanism for Ptch1 to regulate ciliary Smo levels.
  9. Front Endocrinol (Lausanne). 2021 ;12 685228
      Primary cilia (PC) are microtubule-based organelles that are present on nearly all thyroid follicle cells and play an important role in physiological development and in maintaining the dynamic homeostasis of thyroid follicles. PC are generally lost in many thyroid cancers (TCs), and this loss has been linked to the malignant transformation of thyrocytes, which is regulated by PC-mediated signaling reciprocity between the stroma and cancer cells. Restoring PC on TC cells is a possible promising therapeutic strategy, and the therapeutic response and prognosis of TC are associated with the presence or absence of PC. This review mainly discusses the role of PC in the normal thyroid and TC as well as their potential clinical utility.
    Keywords:  cell cycle; ciliogenesis; primary cilium; therapeutic strategy; thyroid cancer
  10. Abdom Radiol (NY). 2021 Jun 26.
      PURPOSE: To evaluate the correlation of 2D shape-based features with magnetic resonance elastography (MRE)-derived liver stiffness and portal hypertension (pHTN) in children with ARPKD-associated congenital hepatic fibrosis.METHODS: In a prospective IRB-approved study, 14 children with ARPKD (mean age ± SD = 13.8 ± 5.8 years) and 14 healthy controls (mean age ± SD = 13.7 ± 3.9 years) underwent liver MRE. A 2D region of interest (ROI) outlining the left liver lobe at the level of the abdominal aorta was drawn on sagittal T2-weighted images. Eight shape features (perimeter, major axis length, maximum diameter, perimeter to surface ratio (PSR), elongation, sphericity, minor axis length, and mesh surface) describing the 2D-ROI were calculated. Spearman's correlation was calculated between shape features and MRE-derived liver stiffness (kPa) (n = 28). Shape features were compared between participants with ARPKD with pHTN (splenomegaly and thrombocytopenia), (n = 4) and without pHTN (n = 8) using the Mann Whitney U test. Receiver operating characteristic (ROC) curves were generated to examine the diagnostic accuracy of shape features in identifying cases with liver stiffness > 2.9 kPa.
    RESULTS: In ARPKD participants and healthy controls, all eight shape features, except elongation, showed moderate to strong correlation with liver stiffness (kPa); the perimeter surface ratio had the strongest correlation (rho = - 0.75, p < 0.001). In ROC analysis, a cut-off of PSR ≤ 0.057 mm-1 gave 100% (95% CI: 59.0-100.0) sensitivity and 100% (95% CI: 83.9-100.0) specificity in identifying ARPKD participants with liver stiffness > 2.9 kPa, with an area under the ROC curve (AUC) of 1.0 (95% CI: 0.88-1.00). Individuals with pHTN had a lower median PSR (mean ± SD = 0.05 ± 0.01) than those without (0.07 ± 0.01; p = 0.027) with an AUC of 0.91 (95% CI: 0.60-0.99) in differentiating the participants with and without pHTN.
    CONCLUSION: Shape-based features of the left liver lobe show potential as non-invasive biomarkers of liver fibrosis and portal hypertension in children with ARPKD.
    Keywords:  ARPKD; Congenital hepatic fibrosis; Elastography; Liver stiffness; Shape
  11. EMBO Rep. 2021 Jun 25. e51902
      Aurora kinase A (AURKA) is a conserved kinase that plays crucial roles in numerous cellular processes. Although AURKA overexpression is frequent in human cancers, its pleiotropic functions and multifaceted regulation present challenges in its therapeutic targeting. Key to overcoming these challenges is to identify and characterize the full range of AURKA interactors, which are often weak and transient. Previous proteomic studies were limited in monitoring dynamic and non-mitotic AURKA interactions. Here, we generate the proximity interactome of AURKA in asynchronous cells, which consists of 440 proteins involving multiple biological processes and cellular compartments. Importantly, AURKA has extensive proximate and physical interactions to centriolar satellites, key regulators of the primary cilium. Loss-of-function experiments identify satellites as negative regulators of AURKA activity, abundance, and localization in quiescent cells. Notably, loss of satellites activates AURKA at the basal body, decreases centrosomal IFT88 levels, and causes ciliogenesis defects. Collectively, our results provide a resource for dissecting spatiotemporal regulation of AURKA and uncover its proteostatic regulation by satellites as a new mechanism for its ciliary functions.
    Keywords:  Aurora Kinase A; BioID; centriolar satellites; centrosome; primary cilium
  12. Front Cell Dev Biol. 2021 ;9 669756
      Digestive diseases have become an important source of morbidity and mortality. The considerable financial and health burdens caused by digestive diseases confirm the importance of extensive research to better understand and treat these diseases. The development of reliable preclinical models is essential for understanding the pathogenesis of digestive diseases and developing treatment and prevention methods. However, traditional established cell lines and animal models still have many limitations in the study of the digestive system. Conditional reprogramming (CR) cell culture is a newly developed primary technology that uses irradiated Swiss-3T3-J2 mouse fibroblast cells and the Rho-associated kinase (ROCK) inhibitor Y-27632 to rapidly and efficiently generate many cells from diseased and normal tissues. CR cells (CRCs) can be reprogrammed to maintain a highly proliferative state and recapitulate the histological and genomic features of the original tissue. Moreover, after removing these conditions, the phenotype was completely reversible. Therefore, CR technology may represent an ideal model to study digestive system diseases, to test drug sensitivity, to perform gene profile analysis, and to undertake xenograft research and regenerative medicine. Indeed, together with organoid cultures, CR technology has been recognized as one of the key new technologies by NIH precision oncology and also used for NCI human cancer model initiatives (HCMI) program with ATCC. In this article, we review studies that use CR technology to conduct research on diseases of the digestive system.
    Keywords:  CR technology; cell culture technology; cell model; conditional cell reprogramming; digestive system diseases
  13. Liver Int. 2021 Jun 21.
      Patients suffering from polycystic liver disease can develop large liver volumes, leading to physical and psychological complaints, reducing quality of life. There is an unmet need for new therapies in these patients. Estrogen seems to be a promising target for new therapies. Female sex is the most important risk factor for the presence and severity of disease, estrogen supplementation enhances liver growth and after menopause, liver growth decreases. Experimental studies show the presence of the estrogen receptors alfa and beta on cystic cholangiocytes, and increased in vitro growth after administration of estrogen. In this review, we summarize the available experimental and epidemiological evidence to unravel the role of estrogens and other female hormones in polycystic liver disease. Based on the available evidence, female polycystic liver disease patients should be discouraged from taking estrogen-containing contraceptives or hormone replacement therapy. Since liver growth rates decline after menopause, treatment decisions should be based on measured liver growth in postmenopausal women. Finally, blockage of estrogen receptors or estrogen production is a promising target for new therapies.
    Keywords:  ADPKD; GnRH analogues; estrogen; polycystic liver disease; progesterone; tamoxifen
  14. Dev Dyn. 2021 Jun 26.
      BACKGROUND: Lymphatic vascular development is regulated by well-characterised signalling and transcriptional pathways. These pathways regulate lymphatic endothelial cell (LEC) migration, motility, polarity and morphogenesis. Canonical and non-canonical WNT signalling pathways are known to control LEC polarity and development of lymphatic vessels and valves. PKD1, encoding Polycystin-1, is the most commonly mutated gene in polycystic kidney disease but has also been shown to be essential in lymphatic vascular morphogenesis. The mechanism by which Pkd1 acts during lymphangiogenesis remains unclear.RESULTS: Here we find that loss of non-canonical WNT signalling components Wnt5a and Ryk phenocopy lymphatic defects seen in Pkd1 knockout mice. To investigate genetic interaction, we generated Pkd1;Wnt5a double knockout mice. Loss of Wnt5a suppressed phenotypes seen in the lymphatic vasculature of Pkd1-/- mice and Pkd1 deletion suppressed phenotypes observed in Wnt5a-/- mice. Thus, we report mutually suppressive roles for Pkd1 and Wnt5a, with developing lymphatic networks restored to a more wild type state in double mutant mice. This genetic interaction between Pkd1 and the non-canonical WNT signalling pathway ultimately controls LEC polarity and the morphogenesis of developing vessel networks.
    CONCLUSION: Our work suggests that Pkd1 acts at least in part by regulating non-canonical WNT signalling during the formation of lymphatic vascular networks. This article is protected by copyright. All rights reserved.
    Keywords:  Polycystin 1, PC1; WNT5A; lymphangiogenesis, vascular, Polycystic kidney disease; planar cell polarity
  15. Br J Cancer. 2021 Jun 25.
      BACKGROUND: Metastasis is a hallmark of cancer and responsible for most cancer deaths. Migrastatics were defined as drugs interfering with all modes of cancer cell invasion and thus cancers' ability to metastasise. First anti-metastatic treatments have recently been approved.METHODS: We used bioinformatic analyses of publicly available melanoma databases. Experimentally, we performed in vitro target validation (including 2.5D cell morphology analysis and mass spectrometric analysis of RhoA binding partners), developed a new traceable spontaneously metastasising murine melanoma model for in vivo validation, and employed histology (haematoxylin/eosin and phospho-myosin II staining) to confirm drug action in harvested tumour tissues.
    RESULTS: Unbiased and targeted bioinformatic analyses identified the Rho kinase (ROCK)-myosin II pathway and its various components as potentially relevant targets in melanoma. In vitro validation demonstrated redundancy of several RhoGEFs upstream of RhoA and confirmed ROCK as a druggable target downstream of RhoA. The anti-metastatic effects of two ROCK inhibitors were demonstrated through in vivo melanoma metastasis tracking and inhibitor effects also confirmed ex vivo by digital pathology.
    CONCLUSIONS: We proposed a migrastatic drug development pipeline. As part of the pipeline, we provide a new traceable spontaneous melanoma metastasis model for in vivo quantification of metastasis and anti-metastatic effects by non-invasive imaging.
  16. Microb Pathog. 2021 Jun 17. pii: S0882-4010(21)00326-0. [Epub ahead of print]158 105054
      The ability of Helicobacter pylori to manipulate host autophagy is an important pathogenic mechanism. We found an inverse correlation between the expression of ILK and the autophagy marker protein LC3B in H. pylori-positive human samples, H. pylori-infected mice models and H. pylori-infected GES-1 cell lines. When the ILK-knockdown GES-1 cells were infected by H. pylori, CagA were significantly degraded, autophagosomes accumulation and autolysosomes formation were significantly increased, and LC3B protein levels and ratio of LC3BII to LC3BI were also remarkably upregulated. And chloroquine treatment increased LC3B levels in ILK-knockdown GES-1 cells. The expression levels of both Rac1 and RhoA were downregulated in GES-1 cells after H. pylori infection and were decreased in ILK-knockdown GES-1 cells. The mRNA and protein levels of PAK1, MLC, and LIMK were significantly decreased and cofilin mRNA and protein levels were significantly increased in GES-1 cells treated with the Rac1 inhibitor NSC 23766. The mRNA and protein levels of ROCK1, ROCK2, MLC, and LIMK1 were significantly reduced and cofilin mRNA and protein levels were significantly increased in GES-1 cells treated with the RhoA inhibitor CCG-1423. F-actin was significantly reduced in Rac1- or RhoA-inhibited GES-1 cells. F-actin depolymerization induced autophagosomes accumulation, autolysosomes formation, and the increase of LC3B levels in GES-1 cells. Therefore, these findings revealed that ILK could serve as a novel regulator to affect Rac1/PAK1 and RhoA/ROCKs signaling pathways, thereby influencing H. pylori-induced autophagy.
    Keywords:  Autophagy; F-actin; H. pylori; ILK; Rac1; RhoA
  17. J Int Med Res. 2021 Jun;49(6): 3000605211021752
      INTRODUCTION: Oxidative stress is a pathologic feature of hyperuricemia that is highly prevalent and that contributes to kidney tubular interstitial fibrosis. Rho-kinase is closely related to mitochondrial-induced oxidative stress. Herein, we designed a study to explore the expression and role of Rho-kinase in hyperuricemia nephropathy. The secondary objective was to investigate whether the Rho-kinase signaling pathway regulates hyperuricemic tubular oxidative injury and apoptosis via the mitochondrial pathway in addition to the mechanisms that are involved.MATERIALS AND METHODS: HK-2 cells were divided into the following five groups: normal; uric acid (UA); UA+Fasudil; UA+ROCK1 si-RNA; and UA+sc-siRNA. Rho-kinase activity, mitochondrial oxidative injury, and apoptosis-related protein levels were measured in each group. A t-test was used to analyze the difference between groups.
    RESULTS: Myosin phosphatase target subunit 1 (MYPT1) overexpression was shown in HK-2 cells, which was caused by UA. High concentrations of UA also up-regulated Rho-kinase expression and mitochondrial and apoptosis-related protein expression, while treatment with fasudil and ROCK1 si-RNA significantly attenuated these responses.
    CONCLUSION: The Rho-kinase signaling pathway participates in tubular mitochondrial oxidative injury and apoptosis via regulating mitochondrial dyneins/biogenic genes in UA nephropathy, which suggests that the mitochondrial pathway might be a potential therapeutic target for hyperuricemia nephropathy.
    Keywords:  Hyperuricemia; Rho kinase; dynein; gene regulation; signaling pathway; tubular mitochondrial oxidative injury; uric acid nephropathy
  18. JHEP Rep. 2021 Jun;3(3): 100251
      The family of vascular endothelial growth factors (VEGFs) includes 5 members (VEGF-A to -D, and placenta growth factor), which regulate several critical biological processes. VEGF-A exerts a variety of biological effects through high-affinity binding to tyrosine kinase receptors (VEGFR-1, -2 and -3), co-receptors and accessory proteins. In addition to its fundamental function in angiogenesis and endothelial cell biology, VEGF/VEGFR signalling also plays a role in other cell types including epithelial cells. This review provides an overview of VEGF signalling in biliary epithelial cell biology in both normal and pathologic conditions. VEGF/VEGFR-2 signalling stimulates bile duct proliferation in an autocrine and paracrine fashion. VEGF/VEGFR-1/VEGFR-2 and angiopoietins are involved at different stages of biliary development. In certain conditions, cholangiocytes maintain the ability to secrete VEGF-A, and to express a functional VEGFR-2 receptor. For example, in polycystic liver disease, VEGF secreted by cystic cells stimulates cyst growth and vascular remodelling through a PKA/RAS/ERK/HIF1α-dependent mechanism, unveiling a new level of complexity in VEFG/VEGFR-2 regulation in epithelial cells. VEGF/VEGFR-2 signalling is also reactivated during the liver repair process. In this context, pro-angiogenic factors mediate the interactions between epithelial, mesenchymal and inflammatory cells. This process takes place during the wound healing response, however, in chronic biliary diseases, it may lead to pathological neo-angiogenesis, a condition strictly linked with fibrosis progression, the development of cirrhosis and related complications, and cholangiocarcinoma. Novel observations indicate that in cholangiocarcinoma, VEGF is a determinant of lymphangiogenesis and of the immune response to the tumour. Better insights into the role of VEGF signalling in biliary pathophysiology might help in the search for effective therapeutic strategies.
    Keywords:  ADPKD, adult dominant polycystic kidney disease; Anti-Angiogenic therapy; BA, biliary atresia; BDL, bile duct ligation; CCA, cholangiocarcinoma; CCl4, carbon tetrachloride; CLDs, chronic liver diseases; Cholangiocytes; Cholangiopathies; DP, ductal plate; DPM, ductal plate malformation; DRCs, ductular reactive cells; Development; HIF-1α, hypoxia-inducible factor type 1α; HSCs, hepatic stellate cells; IHBD, intrahepatic bile ducts; IL-, interleukin-; LECs, lymphatic endothelial cells; LSECs, liver sinusoidal endothelial cells; Liver repair; MMPs, matrix metalloproteinases; PBP, peribiliary plexus; PC, polycystin; PDGF, platelet-derived growth factor; PIGF, placental growth factor; PLD, polycystic liver diseases; Polycystic liver diseases; SASP, senescence-associated secretory phenotype; TGF, transforming growth factor; VEGF, vascular endothelial growth factors; VEGF-A; VEGF/VEGFR-2 signalling; VEGFR-1/2, vascular endothelial growth factor receptor 1/2; mTOR, mammalian target of rapamycin
  19. J Pathol. 2021 Jun 22.
      Micropapillary carcinoma (MPC) is a morphologically distinctive form of carcinoma, composed of small nests of cancer cells surrounded by lacunar spaces. Invasive MPC is associated with poor prognosis. The nests of tumor cells in MPC reportedly exhibit reverse polarity, although the molecular mechanisms underlying MPC patterns are poorly understood. Using the cancer tissue-originated spheroid (CTOS) method, we previously reported polarity switching in colorectal cancer (CRC). When cultured in suspension, the apical membrane promptly switches from the outside surface of the CTOSs to the surface of the lumen inside the CTOSs under extracellular matrix (ECM)-embedded conditions, and vice versa. Here, we investigated two CTOS lines from CRC patient tumors with MPC lesions. Xenograft tumors from the CTOSs exhibited the MPC phenotype. The MPC-CTOSs did not switch polarity in vitro. Time-course analysis of polarity switching using real-time imaging of the apical membrane revealed that local switching was continually propagated in non-MPC-CTOSs, while MPC-CTOSs were unable to complete the process. Integrin β4 translocated to the outer membrane when embedded in ECM in both MPC and non-MPC-CTOSs. Protein levels, as well as the active form of RhoA, were higher in MPC-CTOSs. The suppression of RhoA activity by GAP overexpression enabled MPC-CTOSs to complete polarity switching both in vitro and in vivo, while overexpression of active RhoA did not affect polarity switching in non-MPC-CTOSs. Pretreatment with a ROCK inhibitor enabled MPC-CTOSs to complete polarity switching both in vitro and in vivo, although delayed treatment after becoming embedded in ECM failed to do so. Thus, the inability to polarity switch might be a cause of MPC, in which the aberrant activation of RhoA plays a critical role. This article is protected by copyright. All rights reserved.
    Keywords:  3D Imaging; Colorectal cancer; Micropapillary carcinoma; Organoid; polarity
  20. Tissue Barriers. 2021 Jun 21. 1926190
      In some organs, such as the brain, endothelial cells form a robust and highly selective blood-to-tissue barrier. However, in other organs, such as the intestine, endothelial cells provide less stringent permeability, to allow rapid exchange of solutes and nutrients where needed. To maintain the structural and functional integrity of the highly dynamic blood-brain and gut-vascular barriers, endothelial cells form highly specialized cell-cell junctions, known as adherens junctions and tight junctions. Claudins are a family of four-membrane-spanning proteins at tight junctions and they have both barrier-forming and pore-forming properties. Tissue-specific expression of claudins has been linked to different diseases that are characterized by barrier impairment. In this review, we summarize the more recent progress in the field of the claudins, with particular attention to their expression and function in the blood-brain barrier and the recently described gut-vascular barrier, under physiological and pathological conditions.Abbreviations: 22q11DS 22q11 deletion syndrome; ACKR1 atypical chemokine receptor 1; AD Alzheimer disease; AQP aquaporin; ATP adenosine triphosphate; Aβ amyloid β; BAC bacterial artificial chromosome; BBB blood-brain barrier; C/EBP-α CCAAT/enhancer-binding protein α; cAMP cyclic adenosine monophosphate (or 3',5'-cyclic adenosine monophosphate); CD cluster of differentiation; CNS central nervous system; DSRED discosoma red; EAE experimental autoimmune encephalomyelitis; ECV304 immortalized endothelial cell line established from the vein of an apparently normal human umbilical cord; EGFP enhanced green fluorescent protein; ESAM endothelial cell-selective adhesion molecule; GLUT-1 glucose transporter 1; GVB gut-vascular barrier; H2B histone H2B; HAPP human amyloid precursor protein; HEK human embryonic kidney; JACOP junction-associated coiled coil protein; JAM junctional adhesion molecules; LYVE1 lymphatic vessel endothelial hyaluronan receptor 1; MADCAM1 mucosal vascular addressin cell adhesion molecule 1; MAPK mitogen-activated protein kinase; MCAO middle cerebral artery occlusion; MMP metalloprotease; MS multiple sclerosis; MUPP multi-PDZ domain protein; PATJ PALS-1-associated tight junction protein; PDGFR-α platelet-derived growth factor receptor α polypeptide; PDGFR-β platelet-derived growth factor receptor β polypeptide; RHO rho-associated protein kinase; ROCK rho-associated, coiled-coil-containing protein kinase; RT-qPCR real time quantitative polymerase chain reactions; PDGFR-β soluble platelet-derived growth factor receptor, β polypeptide; T24 human urinary bladder carcinoma cells; TG2576 transgenic mice expressing the human amyloid precursor protein; TNF-α tumor necrosis factor α; WTwild-type; ZO zonula occludens.
    Keywords:  Claudins; blood–brain barrier; gut–vascular barrier; permeability barrier; tight junctions
  21. Stem Cell Res Ther. 2021 Jun 25. 12(1): 362
      BACKGROUND: Vitamin B3 (nicotinamide) plays important roles in metabolism as well as in SIRT and PARP pathways. It is also recently reported as a novel kinase inhibitor with multiple targets. Nicotinamide promotes pancreatic cell differentiation from human embryonic stem cells (hESCs). However, its molecular mechanism is still unclear. In order to understand the molecular mechanism involved in pancreatic cell fate determination, we analyzed the downstream pathways of nicotinamide in the derivation of NKX6.1+ pancreatic progenitors from hESCs.METHODS: We applied downstream modulators of nicotinamide during the induction from posterior foregut to pancreatic progenitors, including niacin, PARP inhibitor, SIRT inhibitor, CK1 inhibitor and ROCK inhibitor. The impact of those treatments was evaluated by quantitative real-time PCR, flow cytometry and immunostaining of pancreatic markers. Furthermore, CK1 isoforms were knocked down to validate CK1 function in the induction of pancreatic progenitors. Finally, RNA-seq was used to demonstrate pancreatic induction on the transcriptomic level.
    RESULTS: First, we demonstrated that nicotinamide promoted pancreatic progenitor differentiation in chemically defined conditions, but it did not act through either niacin-associated metabolism or the inhibition of PARP and SIRT pathways. In contrast, nicotinamide modulated differentiation through CK1 and ROCK inhibition. We demonstrated that CK1 inhibitors promoted the generation of PDX1/NKX6.1 double-positive pancreatic progenitor cells. shRNA knockdown revealed that the inhibition of CK1α and CK1ε promoted pancreatic progenitor differentiation. We then showed that nicotinamide also improved pancreatic progenitor differentiation through ROCK inhibition. Finally, RNA-seq data showed that CK1 and ROCK inhibition led to pancreatic gene expression, similar to nicotinamide treatment.
    CONCLUSIONS: In this report, we revealed that nicotinamide promotes generation of pancreatic progenitors from hESCs through CK1 and ROCK inhibition. Furthermore, we discovered the novel role of CK1 in pancreatic cell fate determination.
    Keywords:  Casein kinase 1 (CK1); Human embryonic stem cells; Kinase inhibitor; Nicotinamide; Pancreatic progenitors; Rho-associated protein kinase (ROCK)
  22. Life Sci. 2021 Jun 16. pii: S0024-3205(21)00711-6. [Epub ahead of print] 119725
      AIMS: Pulmonary hypertension (PH) is a serious lung disease that caused by cellular proliferation, vascular wall inflammation and fibrosis. MicroRNAs (miRNAs) have been known to participate in the pathogenesis of PH and could be used to treat PH. In this study, we investigated the molecular mechanism of a miRNA candidate and its roles in the process of hypoxic PH.MAIN METHODS: The hypoxic PH model was established in SD rats treated with 10% O2 for 21 days. The change of body weight, the hemodynamic index, the right ventricular remodeling index and the pulmonary artery remodeling were monitored during treatments. CCK8 and Transwell assay were applied for detection of the primary pulmonary artery smooth muscle cells (PASMCs) activity and migration.
    KEY FINDINGS: High expression of HIF-1α and low expression of miR-92b-3p were found in pulmonary artery and primary PASMCs of hypoxia-treated rats. Overexpression of miR-92b-3p or suppression of HIF-1α inhibited hypoxia-induced pulmonary remodeling, inflammatory cytokines and proliferation/migration of primary PASMCs. RIP and luciferase reporter gene assay suggested a direct interaction between miR-92b-3p and HIF-1α, and overexpression of miR-92b-3p could inhibit the expression of HIF-1α, RhoA and ROCK activity. Upregulated miR-92b-3p partially reduced inflammatory cytokines, inhibited pulmonary remodeling, and thus alleviating the hypoxic PH. miR-92b-3p could alleviate the hypoxia-induced PH.
    SIGNIFICANCES: Our findings offer basis for better understanding the role of miRNAs in PH.
    Keywords:  Hypoxia; Hypoxia inducible factor 1alpha; MicroRNA-92b-3p; Pulmonary hypertension; RhoA/ROCK signaling
  23. Exp Neurol. 2021 Jun 21. pii: S0014-4886(21)00202-8. [Epub ahead of print] 113794
      Regeneration is bungled following CNS injuries, including spinal cord injury (SCI). Inherent decay of permissive conditions restricts the regrowth of the mature CNS after an injury. Hypertrophic scarring, insignificant intrinsic axon-growth activity, and axon-growth inhibitory molecules such as myelin inhibitors and scar inhibitors constitute a significant hindrance to spinal cord repair. Besides these molecules, a combined absence of various mechanisms responsible for axonal regeneration is the main reason behind the dereliction of the adult CNS to regenerate. The neutralization of specific inhibitors/proteins by stymieing antibodies or encouraging enzymatic degradation results in improved axon regeneration. Previous efforts to induce regeneration after SCI have stimulated axonal development in or near lesion sites, but not beyond them. Several pathways are responsible for the axonal growth obstruction after a CNS injury, including SCI. Herein, we summarize the axonal, glial, and intrinsic factor which impedes the regeneration. We have also discussed the methods to stabilize microtubules and through this to maintain the proper cytoskeletal dynamics of growth cone as disorganized microtubules lead to the failure of axonal regeneration. Moreover, we primarily focus on diverse inhibitors of axonal growth and molecular approaches to counteract them and their downstream intracellular signaling through the RhoA/ROCK pathway.
    Keywords:  CNS injury; CSPG; Microtubules; ROCK; Spinal cord injury