bims-bicyki Biomed News
on Bicaudal-C1 and interactors in cystic kidney disease
Issue of 2021‒04‒11
23 papers selected by
Céline Gagnieux
École Polytechnique Fédérale de Lausanne (EPFL)

  1. J Digit Imaging. 2021 Apr 05.
      Total kidney volume (TKV) is the main imaging biomarker used to monitor disease progression and to classify patients affected by autosomal dominant polycystic kidney disease (ADPKD) for clinical trials. However, patients with similar TKVs may have drastically different cystic presentations and phenotypes. In an effort to quantify these cystic differences, we developed the first 3D semantic instance cyst segmentation algorithm for kidneys in MR images. We have reformulated both the object detection/localization task and the instance-based segmentation task into a semantic segmentation task. This allowed us to solve this unique imaging problem efficiently, even for patients with thousands of cysts. To do this, a convolutional neural network (CNN) was trained to learn cyst edges and cyst cores. Images were converted from instance cyst segmentations to semantic edge-core segmentations by applying a 3D erosion morphology operator to up-sampled versions of the images. The reduced cysts were labeled as core; the eroded areas were dilated in 2D and labeled as edge. The network was trained on 30 MR images and validated on 10 MR images using a fourfold cross-validation procedure. The final ensemble model was tested on 20 MR images not seen during the initial training/validation. The results from the test set were compared to segmentations from two readers. The presented model achieved an averaged R2 value of 0.94 for cyst count, 1.00 for total cyst volume, 0.94 for cystic index, and an averaged Dice coefficient of 0.85. These results demonstrate the feasibility of performing cyst segmentations automatically in ADPKD patients.
    Keywords:  Autosomal dominant polycystic kidney disease; Convolutional neural networks; Cyst volume; Magnetic resonance imaging; Three-dimensional instance segmentation
  2. Cureus. 2021 Feb 25. 13(2): e13561
      Introduction In this study, we aimed to determine the endothelial dysfunction (ED) and atherosclerosis in patients with autosomal dominant polycystic kidney disease (ADPKD). Materials and methods This study was conducted with 83 subjects (26 male, mean age: 46±11 years) consisted of three groups including ADPKD, hypertension (HT) and healthy control groups. The groups were evaluated in terms of serum endocan and asymmetric dimethylarginine (ADMA) levels, flow-mediated dilatation (FMD), nitroglycerin-mediated dilation (NMD) and carotid intima-media thickness (CIMT). Results Serum endocan and ADMA levels and CIMT were significantly higher while NMD was significantly lower in ADPKD group than control group. FMD and NMD were lower but serum ADMA level was higher in the ADPKD group than HT group; while serum endocan level and CIMT were not significantly different in ADPKD and HT groups. In ADPKD patients, CIMT value and serum endocan and ADMA levels were higher while NMD was lower in patients with eGFR≤60 mL/min/1.73 m2 than patients with eGFR>60 mL/min/1.73 m2. Serum ADMA level was higher and NMD was lower in hypertensive ADPKD patients than non-hypertensive ones. Serum endocan level was higher in ADPKD patients with nephrolithiasis and a negative correlation was detected between serum endocan level and 24-hour urine volume. Conclusions Endothelial dysfunction and atherosclerosis are common conditions in ADPKD patients and it was further reinforced in our study. In order to clarify the relationship between serum endocan level and 24-hour urine volume, which is a remarkable finding in our study, larger studies that including the measurement of urine endocan may be useful.
    Keywords:  asymmetric dimethylarginine; atherosclerosis; autosomal-dominant polycystic kidney disease; carotid intima-media thickness; endocan; endothelial dysfunction; flow mediated dilatation; nitroglycerin mediated dilation
  3. FASEB J. 2021 May;35(5): e21533
      Polycystic kidney disease (PKD) is a genetic disorder characterized by aberrant renal epithelial cell proliferation and formation and progressive growth of numerous fluid-filled cysts within the kidneys. Previously, we showed that there is elevated Notch signaling compared to normal renal epithelial cells and that Notch signaling contributes to the proliferation of cystic cells. Quinomycin A, a bis-intercalator peptide, has previously been shown to target the Notch signaling pathway and inhibit tumor growth in cancer. Here, we show that Quinomycin A decreased cell proliferation and cyst growth of human ADPKD cyst epithelial cells cultured within a 3D collagen gel. Treatment with Quinomycin A reduced kidney weight to body weight ratio and decreased renal cystic area and fibrosis in Pkd1RC/RC ; Pkd2+/- mice, an orthologous PKD mouse model. This was accompanied by reduced expression of Notch pathway proteins, RBPjk and HeyL and cell proliferation in kidneys of PKD mice. Quinomycin A treatments also normalized cilia length of cyst epithelial cells derived from the collecting ducts. This is the first study to demonstrate that Quinomycin A effectively inhibits PKD progression and suggests that Quinomycin A has potential therapeutic value for PKD patients.
    Keywords:  Notch; Quinomycin A; polycystic kidney; proliferation
  4. Transl Gastroenterol Hepatol. 2021 ;6 26
      Fibrocystic liver diseases (FLDs) comprise a heterogeneous group of rare diseases of the biliary tree, having in common an abnormal development of the embryonic ductal plate caused by genetically-determined dysfunctions of proteins expressed in the primary cilia of cholangiocytes (and therefore grouped among the "ciliopathies"). The ductal dysgenesis may affect the biliary system at multiple levels, from the small intrahepatic bile ducts [congenital hepatic fibrosis (CHF)], to the larger intrahepatic bile ducts [Caroli disease (CD), or Caroli syndrome (CS), when CD coexists with CHF], leading to biliary microhamartomas and segmental bile duct dilations. Biliary changes are accompanied by progressive deposition of abundant peribiliary fibrosis. Peribiliary fibrosis and biliary cysts are the fundamental lesions of FLDs and are responsible for the main clinical manifestations, such as portal hypertension, recurrent cholangitis, cholestasis, sepsis and eventually cholangiocarcinoma. Furthermore, FLDs often associate with a spectrum of disorders affecting primarily the kidney. Among them, the autosomal recessive polycystic kidney disease (ARPKD) is the most frequent, and the renal function impairment is central in disease progression. CHF, CD/CS, and ARPKD are caused by a number of mutations in polycystic kidney hepatic disease 1 (PKHD1), a gene that encodes for fibrocystin/polyductin, a protein of unclear function, but supposedly involved in planar cell polarity and other fundamental cell functions. Targeted medical therapy is not available yet and thus the current treatment aims at controlling the complications. Interventional radiology or surgical treatments, including liver transplantation, are used in selected cases.
    Keywords:  Caroli disease (CD); Caroli syndrome (CS); Fibrocystic liver disease (FLD); biliary fibrosis; congenital hepatic fibrosis (CHF); polycystic kidney hepatic disease 1 (PKHD1)
  5. Evid Based Complement Alternat Med. 2021 ;2021 6683264
      Background: Rho guanine nucleotide exchange factor 10-like protein (ARHGEF10L) is a member of the guanine nucleotide exchange factor family, which regulates Rho GTPase activities, thus contributing to tumorigenesis. Our previous study demonstrated a strong association between the ARHGEF10L gene and the risk of cervical carcinoma. This study investigated the pathogenic role and mechanism of ARHGEF10L in cervical tumors.Methods: The HeLa cell line, which was derived from cervical carcinoma, was transfected with ARHGEF10L-overexpressing plasmids or anti-ARHGEF10L siRNA. Cell counting kit-8 assays, wound-healing assays, and cell apoptosis assays were performed to investigate the effects of ARHGEF10L on cell activities. A Rho pull-down assay and RNA-sequencing analysis were performed to investigate the pathogenic pathway of ARHGEF10L involvement in cervical tumors.
    Results: ARHGEF10L overexpression promoted cell proliferation and migration, reduced cell apoptosis, and induced epithelial-to-mesenchymal transition (EMT) via downregulation of E-cadherin and upregulation of N-cadherin and Slug in transfected HeLa cells. The overexpression of ARHGEF10L also upregulated GTP-RhoA, ROCK1, and phospho-ezrin/radixin/moesin (ERM) expression in HeLa cells. RNA-sequencing analysis detected altered transcription of 31 genes in HeLa cells with ARHGEF10L overexpression. Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) pathway analyses identified significant differences in cyclin-dependent protein serine/threonine kinase activity, cell responses to vitamin A, and Toll-like receptor signaling pathways. Both real-time PCR and Western blotting verified the increased expression of heat shock 70 kDa protein 6 (HSPA6) in ARHGEF10L-overexpressing HeLa cells. Since we reported that ARHGEF10L played a role through RhoA-ROCK1-ERM signaling, an important pathway in tumorigenesis, and stimulated EMT and HSPA6 expression in liver tumors and gastric tumor cells, we suggest that ARHGEF10L is a novel oncogene in many tumors.
  6. Biochem Biophys Res Commun. 2021 Apr 03. pii: S0006-291X(21)00493-9. [Epub ahead of print]555 190-195
      Primary cilia are microtubule-based organelles that are involved in sensing micro-environmental cues and regulating cellular homeostasis via triggering signaling cascades. Hypoxia is one of the most common environmental stresses that organ and tissue cells may often encounter during embryogenesis, cell differentiation, infection, inflammation, injury, cerebral and cardiac ischemia, or tumorigenesis. Although hypoxia has been reported to promote or inhibit primary ciliogenesis in different tissues or cultured cell lines, the role of hypoxia in ciliogenesis is controversial and still unclear. Here we investigated the primary cilia change under cobalt chloride (CoCl2)-simulated hypoxia in immortalized human retina pigment epithelial-1 (hTERT RPE-1) cells. We found CoCl2 treatment elongated primary cilia in a time- and dose-dependent manner. The prolonged cilia recovered back to near normal length when CoCl2 was washed out from the cell culture medium. Under CoCl2-simulated hypoxia, the protein expression levels of HIF-1/2α and acetylated-α-tubulin (cilia marker) were increased, while the protein expression level of Rabaptin-5 is decreased during hypoxia. Taken together, our results suggest that hypoxia may elongate primary cilia by downregulating Rabaptin-5 involved endocytosis. The coordination between endocytosis and ciliogenesis may be utilized by cells to adapt to hypoxia.
    Keywords:  Cilia length; Cobalt chloride; Endocytosis; Hypoxia; Primary ciliogenesis; Rabaptin-5
  7. Kidney Int. 2021 Apr 05. pii: S0085-2538(21)00359-8. [Epub ahead of print]
      Various cellular insult and injury to renal epithelial cells stimulate repair mechanisms to adapt and restore the organ homeostasis. Renal tubular epithelial cells (RTECs) are endowed with regenerative capacity, which allows for a restoration of nephron function after acute kidney injury (AKI). However, recent evidence indicates that the repair is often incomplete, leading to maladaptive responses that promote the progression to CKD. The dysregulated cell cycle and proliferation is also a key feature of RTECs in polycystic kidney disease (PKD) and HIV-associated nephropathy (HIVAN). Therefore, in this review, we provide an overview of cell cycle regulation and the consequences of dysregulated cell proliferation in AKI, PKD, and HIVAN. An increased understanding of these processes may help define better targets for kidney repair and combat CKD progression.
    Keywords:  Renal tubular epithelial cells; acute kidney injury; and HIVAN; cell cycle; polycystic kidney
  8. FASEB J. 2021 May;35(5): e21570
      The liver is the only visceral organ in the body with a tremendous capacity to regenerate in response to insults that induce inflammation, cell death, and injury. Liver regeneration is a complicated process involving a well-orchestrated activation of non-parenchymal cells in the injured area and proliferation of undamaged hepatocytes. Furthermore, the liver has a Hepatostat, defined as adjustment of its volume to that required for homeostasis. Understanding the mechanisms that control different steps of liver regeneration is critical to informing therapies for liver repair, to help patients with liver disease. The Hippo signaling pathway is well known for playing an essential role in the control and regulation of liver size, regeneration, stem cell self-renewal, and liver cancer. Thus, the Hippo pathway regulates dynamic cell fates in liver, and in absence of its downstream effectors YAP and TAZ, liver regeneration is severely impaired, and the proliferative expansion of liver cells blocked. We will mainly review upstream mechanisms activating the Hippo signaling pathway following partial hepatectomy in mouse model and patients, its roles during different steps of liver regeneration, metabolism, and cancer. We will also discuss how targeting the Hippo signaling cascade might improve liver regeneration and suppress liver tumorigenesis.
    Keywords:  Hippo signaling pathway; liver cancer; liver metabolism; liver regeneration
  9. Sci Adv. 2021 Apr;pii: eabf2629. [Epub ahead of print]7(15):
      Cells in vivo generate mechanical traction on the surrounding 3D extracellular matrix (ECM) and neighboring cells. Such traction and biochemical cues may remodel the matrix, e.g., increase stiffness, which, in turn, influences cell functions and forces. This dynamic reciprocity mediates development and tumorigenesis. Currently, there is no method available to directly quantify single-cell forces and matrix remodeling in 3D. Here, we introduce a method to fulfill this long-standing need. We developed a high-resolution microfabricated sensor that hosts a 3D cell-ECM tissue formed by self-assembly. This sensor measures cell forces and tissue stiffness and can apply mechanical stimulation to the tissue. We measured single and multicellular force dynamics of fibroblasts (3T3), human colon (FET) and lung (A549) cancer cells, and cancer-associated fibroblasts (CAF05) with 1-nN resolution. Single cells show notable force fluctuations in 3D. FET/CAF coculture system, mimicking cancer tumor microenvironment, increased tissue stiffness by three times within 24 hours.
  10. Front Cell Dev Biol. 2021 ;9 603742
      Cell migration is an essential cellular process that requires coordination of cytoskeletal dynamics, reorganization, and signal transduction. The actin cytoskeleton is central in maintaining the cellular structure as well as regulating the mechanisms of cell motility. Glycosylation, particularly sialylation of cell surface proteins like integrins, regulates signal transduction from the extracellular matrix to the cytoskeletal network. The activation of integrin by extracellular cues leads to recruitment of different focal adhesion complex proteins (Src, FAK, paxillin, etc.) and activates the signal including Rho GTPases for the regulation of actin assembly and disassembly. During cell migration, the assembly and disassembly of actin filament provides the essential force for the cell to move. Abnormal sialylation can lead to actin signaling dysfunction leading to aberrant cell migration, one of the main characteristics of cancer and myopathies. In the present study, we have reported altered F-actin to G-actin ratios in GNE mutated cells. These cells exhibit pathologically relevant mutations of GNE (UDP N-acetylneuraminic 2-epimerase/N-acetylmannosamine kinase), a key sialic acid biosynthetic enzyme. It was found that GNE neither affects the actin polymerization nor binds directly to actin. However, mutation in GNE resulted in increased binding of α-actinin to actin filaments. Further, through confocal imaging, GNE was found to be localized in focal adhesion complex along with paxillin. We further elucidated that mutation in GNE resulted in upregulation of RhoA protein and Cofilin activity is downregulated, which could be rescued with Rhosin and chlorogenic acid, respectively. Lastly, mutant in GNE reduced cell migration as implicated from wound healing assay. Our study indicates that molecules altering Cofilin function could significantly revert the cell migration defect due to GNE mutation in sialic acid-deficient cells. We propose cytoskeletal proteins to be alternate drug targets for disorders associated with GNE such as GNE myopathy.
    Keywords:  GNE myopathy; RhoA; actin dynamics; cell migration; cofilin; sialylation
  11. Mol Biol Cell. 2021 Apr 07. mbcE20100685
      Activation of T cells leads to the formation of the immunological synapse (IS) with antigen presenting cells. This requires T cell polarization and coordination between the actomyosin and microtubule cytoskeletons. The interactions between these two cytoskeletal components during T cell activation are not well understood. Here, we elucidate the interactions between microtubules and actin at the IS with high-resolution fluorescence microscopy. We show that microtubule growth dynamics in the peripheral actin-rich region are distinct from those in the central actin-free region. We further demonstrate that these differences arise from differential involvement of Arp2/3- and formin-nucleated actin structures. Formin inhibition results in a moderate decrease in microtubule growth rates, which is amplified in the presence of integrin engagement. In contrast, Arp2/3 inhibition leads to an increase in microtubule growth rates. We find that microtubule filaments are more deformed and exhibit greater shape fluctuations in the periphery of the IS compared to the center. Using small molecule inhibitors, we show that actin dynamics and actomyosin contractility play key roles in defining microtubule deformations and shape fluctuations. Our results indicate a mechanical coupling between the actomyosin and microtubule systems during T cell activation, whereby different actin structures influence microtubule dynamics in distinct ways. [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text].
  12. Front Physiol. 2021 ;12 645857
      Chronic Kidney Disease (CKD) is characterized by organ remodeling and fibrosis due to failed wound repair after on-going or severe injury. Key to this process is the continued activation and presence of matrix-producing renal fibroblasts. In cancer, metabolic alterations help cells to acquire and maintain a malignant phenotype. More recent evidence suggests that something similar occurs in the fibroblast during activation. To support these functions, pro-fibrotic signals released in response to injury induce metabolic reprograming to meet the high bioenergetic and biosynthetic demands of the (myo)fibroblastic phenotype. Fibrogenic signals such as TGF-β1 trigger a rewiring of cellular metabolism with a shift toward glycolysis, uncoupling from mitochondrial oxidative phosphorylation, and enhanced glutamine metabolism. These adaptations may also have more widespread implications with redirection of acetyl-CoA directly linking changes in cellular metabolism and regulatory protein acetylation. Evidence also suggests that injury primes cells to these metabolic responses. In this review we discuss the key metabolic events that have led to a reappraisal of the regulation of fibroblast differentiation and function in CKD.
    Keywords:  TGF-β1; fibroblast; fibrosis; glutaminolysis; glycolysis; metabolic; metabolism; priming
  13. Front Cell Dev Biol. 2021 ;9 630678
      In vitro construction is a major trend involved in cartilage regeneration and repair. Satisfactory in vitro cartilage regeneration depends on a suitable culture system. Current chondrogenic culture systems with a high content of transforming growth factor beta-1 effectively promote cartilaginous extracellular matrix (ECM) production but inhibit chondrocyte survival. As is known, inhibition of the c-Jun N-terminal kinase (JNK) signaling pathway acts in blocking the progression of osteoarthritis by reducing chondrocyte apoptosis and cartilage destruction. However, whether inhibiting JNK signaling resists the inhibitory effect of current chondrogenic medium (CM) on cell survival and affects in vitro auricular cartilage regeneration (including cell proliferation, ECM synthesis, and degradation) has not been investigated. In order to address these issues and optimize the chondrogenic culture system, we generated a three-dimensional in vitro auricular cartilage regeneration model to investigate the effects of SP600125 (a JNK-specific inhibitor) on chondrocyte proliferation and ECM metabolism. SP600125 supplementation efficiently promoted cell proliferation at both cellular and tissue levels and canceled the negative effect of our chondrogenic culture system on cell survival. Moreover, it significantly inhibited ECM degradation by reducing the expressions of tumor necrosis factor-alpha, interleukin-1-beta, and matrix metalloproteinase 13. In addition, SP600125 inhibited ECM synthesis at both cellular and tissue levels, but this could be canceled and even reversed by adding chondrogenic factors; yet this enabled a sufficient number of chondrocytes to be retained at the same time. Thus, SP600125 had a positive effect on in vitro auricular cartilage regeneration in terms of cell proliferation and ECM degradation but a negative effect on ECM synthesis, which could be reversed by adding CM. Therefore, a combination of SP600125 and CM might help in optimizing current chondrogenic culture systems and achieve satisfactory in vitro cartilage regeneration by promoting cell proliferation, reducing ECM degradation, and enhancing ECM synthesis.
    Keywords:  JNK inhibitors; SP600125; cartilage regeneration; cell proliferation; extracellular matrix; in vitro
  14. J Cell Biol. 2021 Jun 07. pii: e202007146. [Epub ahead of print]220(6):
      Activated ezrin-radixin-moesin (ERM) proteins link the plasma membrane to the actin cytoskeleton to generate apical structures, including microvilli. Among many kinases implicated in ERM activation are the homologues LOK and SLK. CRISPR/Cas9 was used to knock out all ERM proteins or LOK/SLK in human cells. LOK/SLK knockout eliminates all ERM-activating phosphorylation. The apical domains of cells lacking LOK/SLK or ERMs are strikingly similar and selectively altered, with loss of microvilli and with junctional actin replaced by ectopic myosin-II-containing apical contractile structures. Constitutively active ezrin can reverse the phenotypes of either ERM or LOK/SLK knockouts, indicating that a central function of LOK/SLK is to activate ERMs. Both knockout lines have elevated active RhoA with concomitant enhanced myosin light chain phosphorylation, revealing that active ERMs are negative regulators of RhoA. As RhoA-GTP activates LOK/SLK to activate ERM proteins, the ability of active ERMs to negatively regulate RhoA-GTP represents a novel local feedback loop necessary for the proper apical morphology of epithelial cells.
  15. Bioengineered. 2021 Dec;12(1): 1138-1149
      Axis formed by integrin β3 (ITGβ3)-Ras homolog gene family, member A (RhoA), and Yes-associated protein (YAP) plays an important role in atherosclerosis. In addition, ITGβ3 overexpression was noted in high-glucose (HG) exposure podocytes. However, the ITGβ3-RhoA-YAP axis on HG-induced podocyte injury remains unclear. This study aimed to investigate whether ITGβ3 regulates podocyte injury by regulating the RhoA-YAP axis. The function and potential mechanism of ITGβ3 were observed through in vitro wound-healing assays, flow cytometry, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and western blot assay. Results showed that HG treatment increased the ability of wound closure and apoptosis; however, in spite of HG treatment, ITGβ3 inhibition mitigated the ability of wound closure and apoptosis in podocytes. By contrast, overexpression of ITGβ3 increased the wound closure and apoptosis abilities of podocytes. Under HG treatment, ITGβ3 knockdown is associated with upregulation of RhoA, total YAP1, and nucleus YAP1, whereas ITGβ3 overexpression has opposite effect. In addition, RhoA overexpression in podocytes reverses the effect of ITGβ3 overexpression on the wound closure and apoptosis abilities of podocytes, rescue the expression of YAP in ITGβ3 overexpression podocytes. Taken together, ITGβ3 overexpression promotes podocytes injury by inhibiting RhoA-YAP axis. This will provide a new clue for preventing podocyte from damage.
    Keywords:  ITGβ3; RhoA/YAP pathway; high glucose; podocyte
  16. J Biol Chem. 2021 Jan 08. pii: S0021-9258(21)00028-4. [Epub ahead of print]296 100261
      GPR56 is a member of the adhesion G-protein-coupled receptor family shown to play important roles in cell adhesion, brain development, immune function, and tumorigenesis. GPR56 is highly upregulated in colorectal cancer and correlates with poor prognosis. Several studies have shown GPR56 couples to the Gα12/13 class of heterotrimeric G-proteins to promote RhoA activation. However, due to its structural complexity and lack of a high-affinity receptor-specific ligand, the complete GPR56 signaling mechanism remains largely unknown. To delineate the activation mechanism and intracellular signaling functions of GPR56, we generated a monoclonal antibody (mAb) that binds with high affinity and specificity to the extracellular domain (ECD). Using deletion mutants, we mapped the mAb binding site to the GAIN domain, which mediates membrane-proximal autoproteolytic cleavage of the ECD. We showed that GPR56 overexpression in 293T cells leads to increased phosphorylation of Src, Fak, and paxillin adhesion proteins and activation of the Gα12/13-RhoA-mediated serum response factor (SRF) pathway. Treatment with the mAb potentiated Src-Fak phosphorylation, RhoA-SRF signaling, and cell adhesion. Consistently, GPR56 knockdown in colorectal cancer cells decreased Src-Fak pathway phosphorylation and cell adhesion. Interestingly, GPR56-mediated activation of Src-Fak phosphorylation occurred independent of RhoA, yet mAb-induced potentiation of RhoA-SRF signaling was Src-dependent. Furthermore, we show that the C-terminal portion of the Serine-Threonine-Proline-rich (STP) region, adjacent to the GAIN domain, was required for Src-Fak activation. However, autoproteolytic cleavage of the ECD was dispensable. These data support a new ECD-dependent mechanism by which GPR56 functions to regulate adhesion through activation of Src-Fak signaling.
    Keywords:  ADGRG1; G-protein-coupled receptor (GPCR); GPR56; Src; cell adhesion; colorectal cancer (CRC); focal adhesion kinase (Fak); monoclonal antibody; paxillin
  17. Semin Cell Dev Biol. 2021 Apr 06. pii: S1084-9521(21)00067-7. [Epub ahead of print]
      Centrosomes were first described by Edouard Van Beneden and named and linked to chromosome segregation by Theodor Boveri around 1870. In the 1960-1980s, electron microscopy studies have revealed the remarkable ultrastructure of a centriole -- a nine-fold symmetrical microtubular assembly that resides within a centrosome and organizes it. Less than two decades ago, proteomics and genomic screens conducted in multiple species identified hundreds of centriole and centrosome core proteins and revealed the evolutionarily conserved nature of the centriole assembly pathway. And now, super resolution microscopy approaches and improvements in cryo-tomography are bringing an unparalleled nanoscale-detailed picture of the centriole and centrosome architecture. In this chapter, we summarize the current knowledge about the architecture of human centrioles. We discuss the structured organization of centrosome components in interphase, focusing on localization/function relationship. We discuss the process of centrosome maturation and mitotic spindle pole assembly in centriolar and acentriolar cells, emphasizing recent literature.
    Keywords:  Centriole; Centrosome; Centrosome maturation; Pericentriolar material
  18. Nat Rev Mol Cell Biol. 2021 Apr 09.
      Fine-tuning cellular physiology in response to intracellular and environmental cues requires precise temporal and spatial control of gene expression. High-resolution imaging technologies to detect mRNAs and their translation state have revealed that all living organisms localize mRNAs in subcellular compartments and create translation hotspots, enabling cells to tune gene expression locally. Therefore, mRNA localization is a conserved and integral part of gene expression regulation from prokaryotic to eukaryotic cells. In this Review, we discuss the mechanisms of mRNA transport and local mRNA translation across the kingdoms of life and at organellar, subcellular and multicellular resolution. We also discuss the properties of messenger ribonucleoprotein and higher order RNA granules and how they may influence mRNA transport and local protein synthesis. Finally, we summarize the technological developments that allow us to study mRNA localization and local translation through the simultaneous detection of mRNAs and proteins in single cells, mRNA and nascent protein single-molecule imaging, and bulk RNA and protein detection methods.
  19. Bioact Mater. 2021 Oct;6(10): 3343-3357
      Periprosthetic osteolysis (PPO) remains the key factor in implant failure and subsequent revision surgery and is mainly triggered by wear particles. Previous studies have shown that inhibition of osteoblastic differentiation is the most widespread incident affecting the interface of trabecular and loosening prostheses. Additionally, the NLRP3 inflammasome is activated by prosthetic particles. Sirtuin3, an NAD+-dependent deacetylase of mitochondria, regulates the function of mitochondria in diverse activities. However, whether SIRT3 can mitigate wear debris-induced osteolysis by inhibiting the NLRP3 inflammasome and enhancing osteogenesis has not been previously reported. Therefore, we investigated the role of SIRT3 during the process of titanium (Ti) particle-induced osteolysis. We revealed that upregulated SIRT3 dramatically attenuated Ti particle-induced osteogenic inhibition through suppression of the NLRP3 inflammasome and improvement of osteogenesis in vivo and in vitro. Moreover, we found that SIRT3 interference in the process of Ti particle-induced osteolysis relied on the GSK-3β/β-catenin signalling pathway. Collectively, these findings indicated that SIRT3 may serve as a rational new treatment against debris-induced PPO by deacetylase-dependent inflammasome attenuation.
    Keywords:  NLRP3 inflammasome; Osteoblast; Periprosthetic osteolysis; SIRT3; Titanium particles
  20. J Cell Physiol. 2021 Apr 06.
      The last two decades have witnessed a tremendous increase in cell biology data. Not least is this true for studies of the dynamic organization of the microfilament and microtubule systems in animal cells where analyses of the molecular components and their interaction patterns have deepened our understanding of these complex force-generating machineries. Previous observations of a molecular cross-talk between the two systems have now led to the realization of the existence of several intricate mechanisms operating to maintain their coordinated cellular organization. In this short review, we relate to this development by discussing new results concerning the function of the actin regulator profilin 1 as a control component of microfilament-microtubule cross-talk.
    Keywords:  actin microtubule cross-talk; cell migration; cytoarchitecture regulation; cytoskeletal control; profilin
  21. J Pathol. 2021 Apr 08.
      Many chronic diseases are marked by fibrosis, which is defined by an abundance of activated fibroblasts and excessive deposition of extracellular matrix, resulting in loss of normal function of the affected organs. The initiation and progression of fibrosis are elaborated by profibrotic cytokines, the most critical of which is transforming growth factor-β1 (TGF-β1). This review focuses on the fibrogenic roles of increased TGF-β activities and underlying signaling mechanisms in the activated fibroblast population and other cell types that contribute to progression of fibrosis. Insight into these roles and mechanisms of TGF-β as universal driver of fibrosis have stimulated the development of therapeutic interventions to attenuate fibrosis progression, based on interference with TGF-β signaling. Their promise in preclinical and clinical settings will be discussed. This article is protected by copyright. All rights reserved.
  22. Cell Calcium. 2021 Mar 27. pii: S0143-4160(21)00058-0. [Epub ahead of print]96 102404
      To elucidate S100 protein-mediated signaling pathways, we attempted to identify novel binding partners for S100A2 by screening protein arrays carrying 19,676 recombinant glutathione S-transferase (GST)-fused human proteins with biotinylated S100A2. Among newly discovered putative S100A2 interactants, including TMLHE, TRH, RPL36, MRPS34, CDR2L, OIP5, and MED29, we identified and characterized the tubulin polymerization-promoting protein (TPPP) as a novel S100A2-binding protein. We confirmed the interaction of TPPP with Ca2+/S100A2 by multiple independent methods, including the protein array method, S100A2 overlay, and pulldown assay in vitro and in transfected COS-7 cells. Based on the results from the S100A2 overlay assay using various GST-TPPP mutants, the S100A2-binding region was identified in the C-terminal (residues 111-160) of the central core domain of a monomeric form of TPPP that is involved in TPPP dimerization. Chemical cross-linking experiments indicated that S100A2 suppresses dimer formation of His-tagged TPPP in a dose-dependent and a Ca2+-dependent manner. In addition to S100A2, TPPP dimerization is disrupted by other multiple S100 proteins, including S100A6 and S100B, in a Ca2+-dependent manner but not by S100A4. This is consistent with the fact that S100A6 and S100B, but not S100A4, are capable of interacting with GST-TPPP in the presence of Ca2+. Considering these results together, TPPP was identified as a novel target for S100A2, and it is a potential binding target for other multiple S100 proteins, including S100A6 and S100B. Direct binding of the S100 proteins with TPPP may cause disassembly of TPPP dimer formation in response to the increasing concentration of intracellular Ca2+, thus resulting in the regulation of the physiological function of TPPP, such as microtubule organization.
    Keywords:  Calcium signaling; Dimerization; Genomewide screening; Intracellular calcium signal transduction; Microtubule organization; Multiple system atrophy; Oligodendrocytes; Parkinson's disease; Protein active array; Protein-protein interaction; S100A2; S100A6; S100B; TPPP; Tubulin polymerization-promoting protein; α-Synuclein