bims-bicyki Biomed News
on Bicaudal-C1 and interactors in cystic kidney disease
Issue of 2022‒03‒13
thirteen papers selected by
Céline Gagnieux
École Polytechnique Fédérale de Lausanne (EPFL)
  1. c-JUN n-Terminal Kinase (JNK) Signaling in Autosomal Dominant Polycystic Kidney Disease.
  2. Endocannabinoid System in Polycystic Kidney Disease.
  3. Germline Mutations for Kidney Volume in ADPKD.
  4. Primary URECs: a source to better understand the pathology of renal tubular epithelia in pediatric hereditary cystic kidney diseases.
  5. A protocol for generation and live-cell imaging analysis of primary cilia reporter cell lines.
  6. ALW-II-41-27, an EphA2 inhibitor, inhibits proliferation, migration and invasion of cervical cancer cells via inhibition of the RhoA/ROCK pathway.
  7. ALKBH3-dependent m1A demethylation of Aurora A mRNA inhibits ciliogenesis.
  8. Effect of cadmium on Rho GTPases signal transduction during osteoclast differentiation.
  9. Renal mitochondrial injury in the pathogenesis of CKD: mtDNA and mitomiRs.
  10. PCARE requires coiled coil, RP62 kinase binding, and EVH1 domain binding motifs for ciliary expansion.
  11. Rho Kinase regulates neutrophil NET formation that is involved in UVB-induced skin inflammation.
  12. Mechanosensitive calcium flashes promote sustained RhoA activation during tight junction remodeling.
  13. DMBT1 is upregulated in cystic fibrosis, affects ciliary motility, and is reduced by acetylcysteine.
  1. J Cell Signal. 2022 ;3(1): 62-78
    c-JUN n-Terminal Kinase (JNK) Signaling in Autosomal Dominant Polycystic Kidney Disease.
    Abigail O Smith, Julie A Jonassen, Kenley M Preval, Roger J Davis, Gregory J Pazour.
      Polycystic kidney disease is an inherited degenerative disease in which the uriniferous tubules are replaced by expanding fluid-filled cysts that ultimately destroy organ function. Autosomal dominant polycystic kidney disease (ADPKD) is the most common form, afflicting approximately 1 in 1,000 people and is caused by mutations in the transmembrane proteins polycystin-1 (Pkd1) and polycystin-2 (Pkd2). The mechanisms by which polycystin mutations induce cyst formation are not well understood, however pro-proliferative signaling must be involved for tubule epithelial cell number to increase over time. We recently found that the stress-activated mitogen-activated protein kinase (MAPK) pathway c-Jun N-terminal kinase (JNK) pathway is activated in cystic disease and genetically removing JNK reduces cyst growth driven by a loss of Pkd2. This review covers the current state of knowledge of signaling in ADPKD with an emphasis on the JNK pathway.
    Keywords:  Cilia; Jun N Terminal kinase; Mitogen-activated protein kinase signaling; Mus musculus; Polycystic kidney disease; Polycystin-1; Polycystin-2
    DOI:  https://doi.org/10.33696/Signaling.3.068
  2. Am J Nephrol. 2022 Mar 09. 1-9
    Endocannabinoid System in Polycystic Kidney Disease.
    Jost Klawitter, Cristina Sempio, Matthew J Jackson, Peter H Smith, Katharina Hopp, Michel Chonchol, Berenice Y Gitomer, Uwe Christians, Jelena Klawitter.
      INTRODUCTION: Autosomal dominant polycystic kidney disease (ADPKD) is a commonly inherited disorder characterized by renal cyst formation. A major pathological feature of ADPKD is the development of interstitial inflammation. The endocannabinoid (EC) system is present in the kidney and has recently emerged as an important player in inflammation and the pathogenesis of progressive kidney disease.METHODS: Data on ECs were collected using a validated mass spectrometry assay from a well-characterized cohort of 102 ADPKD patients (at baseline and after 2- and 4 years on standard vs. rigorous blood-pressure control) and compared to 100 healthy subjects.
    RESULTS: Compared to healthy individuals, we found higher interleukins-6 and -1b as well as reduced plasma levels of anandamide (AEA), 2-arachidonoyl-glycerol (2-AG), and their congeners in ADPKD patients. Baseline AEA concentration negatively associated with the progression of ADPKD as expressed by the yearly percent change in height-corrected total kidney volume and positively with the yearly change in renal function (measured as estimated glomerular filtration rate, ΔeGFR). AEA analog palmitoylethanolamide (PEA) is also associated positively with the yearly change in eGFR.
    DISCUSSION AND CONCLUSION: The results of the present study suggest that ADPKD patients present with lower levels of ECs and that reestablishing the normality of the renal EC system via augmentation of AEA, PEA, and 2-AG levels, either through the increase of their synthesis or through a reduction of their degradation, could be beneficial and may present a promising therapeutic target in said patients.
    Keywords:  2-Arachidonoylglycerol; Anandamide; Autosomal dominant polycystic kidney disease; Endocannabinoids
    DOI:  https://doi.org/10.1159/000522113
  3. Kidney Int Rep. 2022 Mar;7(3): 537-546
    Germline Mutations for Kidney Volume in ADPKD.
    Hiroshi Kataoka, Rie Yoshida, Naomi Iwasa, Masayo Sato, Shun Manabe, Keiko Kawachi, Shiho Makabe, Taro Akihisa, Yusuke Ushio, Atsuko Teraoka, Ken Tsuchiya, Kosaku Nitta, Toshio Mochizuki.
      Introduction: Valid prediction models or predictors of disease progression in children and young patients with autosomal dominant polycystic kidney disease (ADPKD) are lacking. Although total kidney volume (TKV) and Mayo imaging classification are generally used to predict disease progression in patients with ADPKD, it remains unclear whether germline mutation types are associated with these factors. We therefore investigated the association between mutation type and TKV and Mayo imaging classification among patients with ADPKD.Methods: A total of 129 patients with ADPKD who underwent genetic analyses were enrolled in the study. The associations between the severity of PKD (TKV ≥ 1000 ml and Mayo classes 1C-1E) and the PKD1 mutation types (nonsense mutation, frameshift or splicing mutation, and substitution) were evaluated.
    Results: Among the mutation types, only PKD1 splicing/frameshift mutation had significant associations with TKV ≥ 1000 ml in sex-adjusted and multivariable logistic analyses. Similarly, only the PKD1 splicing/frameshift mutation was significantly associated with Mayo 1C-1E in sex-adjusted and multivariable logistic analyses. PKD1 nonsense mutation, PKD1 substitution, or PKD1 mutation position had no significant association with TKV ≥ 1000 ml or Mayo 1C-1E.
    Conclusion: Kidney cyst severity differs according to the mutation types in PKD1. Patients with PKD1 splicing mutations or PKD1 frameshift mutations are associated with TKV ≥ 1000 ml or Mayo 1C-1E. Detailed assessment of mutation types may be useful for predicting renal prognosis in patients with ADPKD and may especially contribute to the care of a high-risk group of children with ADPKD.
    Keywords:  Mayo imaging classification; autosomal dominant polycystic kidney disease; frameshift mutation; germline mutation; kidney volume; splicing mutation
    DOI:  https://doi.org/10.1016/j.ekir.2021.12.012
  4. Orphanet J Rare Dis. 2022 Mar 09. 17(1): 122
    Primary URECs: a source to better understand the pathology of renal tubular epithelia in pediatric hereditary cystic kidney diseases.
    Wolfgang H Ziegler, Sarah Lüdiger, Fatima Hassan, Margarita E Georgiadis, Kathrin Swolana, Amrit Khera, Arne Mertens, Doris Franke, Kai Wohlgemuth, Mareike Dahmer-Heath, Jens König, Claudia Dafinger, Max C Liebau, Metin Cetiner, Carsten Bergmann, Birga Soetje, Dieter Haffner.
      BACKGROUND: In pediatric hereditary cystic kidney diseases, epithelial cell defects mostly result from rare, autosomal recessively inherited pathogenic variants in genes encoding proteins of the cilia-centrosome complex. Consequences of individual gene variants on epithelial function are often difficult to predict and can furthermore depend on the patient's genetic background. Here, we studied urine-derived renal tubular epithelial cells (URECs) from genetically determined, pediatric cohorts of different hereditary cystic kidney diseases, comprising autosomal recessive polycystic kidney disease, nephronophthisis (NPH) and the Bardet Biedl syndrome (BBS). UREC characteristics and behavior in epithelial function-related 3D cell culture were compared in order to identify gene and variant-specific properties and to determine aspects of epithelial (cell) dysfunction.RESULTS: UREC preparations from patients (19) and healthy controls (39) were studied in a qualitative and quantitative manner using primary cells cultured for up-to 21 days. In patients with biallelic pathogenic variants in PKHD1 or NPHP genes, we were able to receive satisfactory amounts of URECs of reproducible quality. In BBS patients, UREC yield was lower and more dependent on the individual genotype. In contrast, in UREC preparations derived from healthy controls, no predictable and satisfactory outcome could be established. Considering cell proliferation, tubular origin and epithelial properties in 2D/3D culture conditions, we observed distinct and reproducible epithelial properties of URECs. In particular, the cells from patients carrying PKHD1 variants were characterized by a high incidence of defective morphogenesis of monolayered spheroids-a property proposed to be suitable for corrective intervention. Furthermore, we explored different ways to generate reference cell lines for both-patients and healthy controls-in order to eliminate restrictions in cell number and availability of primary URECs.
    CONCLUSIONS: Ex vivo 3D cell culture of primary URECs represents a valuable, non-invasive source to evaluate epithelial cell function in kidney diseases and as such helps to elucidate the functional consequences of rare genetic disorders. In combination with genetically defined control cell lines to be generated in the future, the cultivation of primary URECs could become a relevant tool for testing personalized treatment of epithelial dysfunction in patients with hereditary cystic kidney disease.
    Keywords:  3D culture; Children; Epithelial morphogenesis; Hereditary cystic kidney diseases; Personalized medicine; Spheroids; Urine-derived renal tubular epithelial cells (URECs)
    DOI:  https://doi.org/10.1186/s13023-022-02265-1
  5. STAR Protoc. 2022 Mar 18. 3(1): 101199
    A protocol for generation and live-cell imaging analysis of primary cilia reporter cell lines.
    Lucia Binó, Erika Mikulenková, Luděk Štepánek, Ondřej Bernatík, David Vysloužil, Petra Pejšková, Peter Gorilák, Martina Huranová, Vladimír Varga, Lukáš Čajánek.
      Primary cilia are hair-like sensory organelles protruding from the surface of most human cells. As cilia are dynamic, several aspects of their biology can only be revealed by real-time analysis in living cells. Here we describe the generation of primary cilia reporter cell lines. Furthermore, we provide a detailed protocol of how to use the reporter cell lines for live-cell imaging microscopy analysis of primary cilia to study their growth as well as intraciliary transport. For complete details on the use and execution of this protocol, please refer to Bernatik et al. (2020) and Pejskova et al. (2020).
    Keywords:  Cell Biology; Cell culture; Microscopy; Molecular Biology
    DOI:  https://doi.org/10.1016/j.xpro.2022.101199
  6. Oncol Lett. 2022 Apr;23(4): 129
    ALW-II-41-27, an EphA2 inhibitor, inhibits proliferation, migration and invasion of cervical cancer cells via inhibition of the RhoA/ROCK pathway.
    Xiang Li, Dan Li, Rong Ma.
      Recent studies have shown that the Eph receptor A2 (EphA2) and its inhibitor ALW-II-41-27 could regulate various cellular processes in several types of cancer. However, the manner in which ALW-II-41-27 affects the development of cervical cancer (CC) remains unknown. The present study aimed to evaluate the role of ALW-II-41-27 in inhibiting the proliferation, invasion and migration of human papilloma virus-positive CC cells and to verify whether Ras homolog family member A (RhoA)/Rho-associated protein kinase (ROCK) may be a crucial pathway involved in this process. Reverse transcription-quantitative PCR and western blotting analyses indicated an upregulation of EphA2 expression in CC cell lines (HeLa and CaSki). Furthermore, the results from MTT and colony formation assays indicated that ALW-II-41-27 inhibited cell proliferation. Results from wound healing and Transwell assays further demonstrated the inhibitory effect of ALW-II-41-27 on CaSki and HeLa cell migration and invasion, respectively. Furthermore, ALW-II-41-27 inhibited the protein expression of GTP-RhoA and ROCK1 in CaSki and HeLa cells. In addition, the ALW-II-41-27-induced inhibition of the biological function of CaSki and HeLa cells was promoted by cell co-culture with RhoA and ROCK inhibitors. Taken together, the present findings revealed that ALW-II-41-27 inhibited CC cell proliferation, migration and invasion by blocking the RhoA/ROCK pathway. These findings provide further insight into the mechanism of CC progression and significant information for the development of potential therapeutic targets for CC.
    Keywords:  ALW-II-41-27; Eph receptor A2; Ras homolog family member A/Rho-associated protein kinase; cervical cancer; invasion; migration; proliferation
    DOI:  https://doi.org/10.3892/ol.2022.13249
  7. Cell Discov. 2022 Mar 11. 8(1): 25
    ALKBH3-dependent m1A demethylation of Aurora A mRNA inhibits ciliogenesis.
    Wenjun Kuang, Hao Jin, Feng Yang, Xiying Chen, Jianzhao Liu, Ting Li, Yongxia Chang, Min Liu, Zhangqi Xu, Chunxiao Huo, Xiaoyi Yan, Yuehong Yang, Wei Liu, Qiang Shu, Shanshan Xie, Tianhua Zhou.
      Primary cilia are antenna-like subcellular structures to act as signaling platforms to regulate many cellular processes and embryonic development. m1A RNA modification plays key roles in RNA metabolism and gene expression; however, the physiological function of m1A modification remains largely unknown. Here we find that the m1A demethylase ALKBH3 significantly inhibits ciliogenesis in mammalian cells by its demethylation activity. Mechanistically, ALKBH3 removes m1A sites on mRNA of Aurora A, a master suppressor of ciliogenesis. Depletion of ALKBH3 enhances Aurora A mRNA decay and inhibits its translation. Moreover, alkbh3 morphants exhibit ciliary defects, including curved body, pericardial edema, abnormal otoliths, and dilation in pronephric ducts in zebrafish embryos, which are significantly rescued by wild-type alkbh3, but not by its catalytically inactive mutant. The ciliary defects caused by ALKBH3 depletion in both vertebrate cells and embryos are also significantly reversed by ectopic expression of Aurora A mRNA. Together, our data indicate that ALKBH3-dependent m1A demethylation has a crucial role in the regulation of Aurora A mRNA, which is essential for ciliogenesis and cilia-associated developmental events in vertebrates.
    DOI:  https://doi.org/10.1038/s41421-022-00385-3
  8. Environ Toxicol. 2022 Mar 08.
    Effect of cadmium on Rho GTPases signal transduction during osteoclast differentiation.
    Shuangjiang He, Kanglei Zhang, Ying Cao, Gang Liu, Hui Zou, Ruilong Song, Zongping Liu.
      Osteoclasts are the key target cells for cadmium (Cd)-induced bone metabolism diseases, while Rho GTPases play an important role in osteoclast differentiation and bone resorption. To identify new therapeutic targets of Cd-induced bone diseases; we evaluated signal transduction through Rho GTPases during osteoclast differentiation under the influence of Cd. In osteoclastic precursor cells, 10 nM Cd induced pseudopodia stretching, promoted cell migration, upregulated the levels of Cdc42, and RhoQ mRNAs and downstream Rho-associated coiled-coil kinase 1 (ROCK1) and ROCK2 proteins, and downregulated the actin-related protein 2/3 (ARP2/3) levels. Cd at 2 and 5 μM shortened the pseudopodia, inhibited cell migration, and decreased ROCK1, ROCK2, and ARP2/3 protein levels; Cd at 5 μM also reduced the mRNA expression levels of Rac1, Rac2, and RhoU mRNAs and decreased the level of phosphorylated (p)-cofilin. In osteoclasts, 10 nM Cd induced the formation of sealing zones, slightly upregulated Cdc42 mRNA levels and ROCK2 and ARP2/3 protein levels and significantly reduced p-cofilin levels. Cd at 2 μM and 5 μM Cd blocked the fusion of precursor cells; and 5 μM Cd downregulated the expression levels of RhoB, Rac1, Rac3, and RhoU mRNAs, and ROCK1, p-cofilin and ARP2/3 protein levels, significantly. In vivo, Cd (at 5 or 25 mg/L) increased the levels of key proteins RhoA, Rac1/2/3, Cdc42, and RhoU and their mRNAs in bone marrow cells. In summary, the results suggested that Cd affected the differentiation process of osteoclast and altered the expression of several Rho GTPases, which might be crucial targets of Cd during the differentiation of osteoclasts.
    Keywords:  RAW264.7 cells; Rho GTPase; bone; cadmium; cytoskeleton; osteoclasts
    DOI:  https://doi.org/10.1002/tox.23510
  9. Clin Sci (Lond). 2022 Mar 18. 136(5): 345-360
    Renal mitochondrial injury in the pathogenesis of CKD: mtDNA and mitomiRs.
    Maria V Irazabal, Alejandro R Chade, Alfonso Eirin.
      Chronic kidney disease (CKD) is a public health concern that affects over 200 million people worldwide and is associated with a tremendous economic burden. Therefore, deciphering the mechanisms underpinning CKD is crucial to decelerate its progression towards end-stage renal disease (ESRD). Renal tubular cells are populated with a high number of mitochondria, which produce cellular energy and modulate several important cellular processes, including generation of reactive oxygen species (ROS), calcium homeostasis, proliferation, and apoptosis. Over the past few years, increasing evidence has implicated renal mitochondrial damage in the pathogenesis of common etiologies of CKD, such as diabetes, hypertension, metabolic syndrome (MetS), chronic renal ischemia, and polycystic kidney disease (PKD). However, most compelling evidence is based on preclinical studies because renal biopsies are not routinely performed in many patients with CKD. Previous studies have shown that urinary mitochondrial DNA (mtDNA) copy numbers may serve as non-invasive biomarkers of renal mitochondrial dysfunction. Emerging data also suggest that CKD is associated with altered expression of mitochondria-related microRNAs (mitomiRs), which localize in mitochondria and regulate the expression of mtDNA and nucleus-encoded mitochondrial genes. This review summarizes relevant evidence regarding the involvement of renal mitochondrial injury and dysfunction in frequent forms of CKD. We further provide an overview of non-invasive biomarkers and potential mechanisms of renal mitochondrial damage, especially focusing on mtDNA and mitomiRs.
    Keywords:  Chronic kidney disease; Metabolic syndrome; Mitochondria; PKD; microRNA; mtDNA
    DOI:  https://doi.org/10.1042/CS20210512
  10. Hum Mol Genet. 2022 Mar 07. pii: ddac057. [Epub ahead of print]
    PCARE requires coiled coil, RP62 kinase binding, and EVH1 domain binding motifs for ciliary expansion.
    Tess A V Afanasyeva, Yan-Ting Schnellbach, Toby J Gibson, Ronald Roepman, Rob W J Collin.
      Retinitis Pigmentosa (RP) is a genetically heterogeneous form of inherited retinal disease that leads to progressive visual impairment. One genetic subtype of RP, RP54, has been linked to mutations in PCARE (Photoreceptor Cilium Actin Regulator). We have recently shown that PCARE recruits WASF3 to the tip of a primary cilium, and thereby activates an Arp2/3 complex which results in the remodeling of actin filaments that drives the expansion of the ciliary tip membrane. Based on these findings, and the lack of proper photoreceptor development in mice lacking Pcare, we postulated that PCARE plays an important role in photoreceptor outer segment disk formation. In this study, we aimed to decipher the relationship between predicted structural and function amino acid motifs within PCARE and its function. Our results show that PCARE contains a predicted helical coiled coil domain together with evolutionary conserved binding sites for photoreceptor kinase MAK (type RP62), as well as EVH1 domain binding linear motifs. Upon deletion of the helical domain, PCARE failed to localize to the cilia. Furthermore, upon deletion of the EVH1 domain binding motifs separately or together, co-expression of mutant protein with WASF3 resulted in smaller ciliary tip membrane expansions. Finally, inactivation of the lipid modification on the cysteine residue at amino acid position 3 also caused a moderate decrease in the sizes of ciliary tip expansions. Taken together, our data illustrate the importance of amino acid motifs and domains within PCARE in fulfilling its physiological function.
    DOI:  https://doi.org/10.1093/hmg/ddac057
  11. Theranostics. 2022 ;12(5): 2133-2149
    Rho Kinase regulates neutrophil NET formation that is involved in UVB-induced skin inflammation.
    Minghui Li, Xing Lyu, James Liao, Victoria P Werth, Ming-Lin Liu.
      Objective: Ultraviolet B (UVB) is an important trigger of skin inflammation and lupus with leukocyte recruitment to inflamed skin. We recently reported the involvement of neutrophil NETosis in UVB-induced skin inflammation, and that NETotic nuclear envelope rupture is driven by PKCα-mediated nuclear lamin B disassembly. To address the role of Actin cytoskeleton in NETosis, we investigated the effects of Rho kinase (ROCK) and its downstream actomyosin cytoskeletal networks on PKCα nuclear translocation and NET formation, as well as their involvement in UVB-induced skin inflammation. Methods: We studied the dynamic changes of ROCK and actomyosin cytoskeletal networks during NETosis induction and their involvement in PKCα nuclear translocation. Using mice with hematopoietic-specific ROCK1 deficiency, we investigated the effects of ROCK1 deficiency on NETosis, and its involvement in UVB-induced skin inflammation. Results: Our time course studies demonstrated the dynamic changes of actin polymerization and ROCK activation, support the role of actin cytoskeleton in nuclear translocation of cytosolic PKCα in early stage of NETosis induction. Inhibition of actin polymerization or key molecules of the ROCK/MLCK/myosin pathway decreased PKCα nuclear translocation and NET formation. Genetic deficiency of ROCK1, inhibited NETosis ex vivo and in vivo, decreased extracellular display of NET-associated IL-17A, TNFα, IFNγ, and IFNα in inflamed skin, which were correlated with the ameliorated skin inflammation in UVB-irradiated mice with hematopoietic-specific ROCK1 deficiency. Conclusions: ROCK regulated NETosis through modulation of PKCα nuclear translocation via actomyosin cytoskeletal networks in neutrophils. ROCK1 deficiency ameliorated UVB-induced skin inflammation by attenuation of NETosis and NET-associated cytokines.
    Keywords:  NETosis; Neutrophil; Rho kinase; Skin inflammation; UVB
    DOI:  https://doi.org/10.7150/thno.66457
  12. J Cell Biol. 2022 Apr 04. pii: e202105107. [Epub ahead of print]221(4):
    Mechanosensitive calcium flashes promote sustained RhoA activation during tight junction remodeling.
    Saranyaraajan Varadarajan, Shahana A Chumki, Rachel E Stephenson, Eileen R Misterovich, Jessica L Wu, Claire E Dudley, Ivan S Erofeev, Andrew B Goryachev, Ann L Miller.
      Epithelial cell-cell junctions remodel in response to mechanical stimuli to maintain barrier function. Previously, we found that local leaks in tight junctions (TJs) are rapidly repaired by local, transient RhoA activation, termed "Rho flares," but how Rho flares are regulated is unknown. Here, we discovered that intracellular calcium flashes and junction elongation are early events in the Rho flare pathway. Both laser-induced and naturally occurring TJ breaks lead to local calcium flashes at the site of leaks. Additionally, junction elongation induced by optogenetics increases Rho flare frequency, suggesting that Rho flares are mechanically triggered. Depletion of intracellular calcium or inhibition of mechanosensitive calcium channels (MSCs) reduces the amplitude of calcium flashes and diminishes the sustained activation of Rho flares. MSC-dependent calcium influx is necessary to maintain global barrier function by regulating reinforcement of local TJ proteins via junction contraction. In all, we uncovered a novel role for MSC-dependent calcium flashes in TJ remodeling, allowing epithelial cells to repair local leaks induced by mechanical stimuli.
    DOI:  https://doi.org/10.1083/jcb.202105107
  13. Mol Cell Pediatr. 2022 Mar 05. 9(1): 4
    DMBT1 is upregulated in cystic fibrosis, affects ciliary motility, and is reduced by acetylcysteine.
    Alexander Kiefer, Erika Plattner, Renate Ruppel, Christel Weiss, Zhe Zhou-Suckow, Marcus Mall, Marcus Renner, Hanna Müller.
      BACKGROUND: Cystic fibrosis (CF) is the most common genetic disorder in the Caucasian population. Despite remarkable improvements in morbidity and mortality during the last decades, the disease still limits survival and reduces quality of life of affected patients. Moreover, CF still represents substantial economic burden for healthcare systems. Inflammation and infection already start in early life and play important roles in pulmonary impairment. The aim of this study is to analyze the potential role of DMBT1, a protein with functions in inflammation, angiogenesis, and epithelial differentiation, in CF.RESULTS: Immunohistochemically DMBT1 protein expression was upregulated in lung tissues of CF patients compared to healthy controls. Additionally, pulmonary expression of Dmbt1 was approximately 6-fold increased in an established transgenic mouse model of CF-like lung disease (ENaC tg) compared to wild-type mice as detected by qRT-PCR. Since acetylcysteine (ACC) has been shown to reduce inflammatory markers in the airways, its potential influence on DMBT1 expression was analyzed. A549 cells stably transfected with an expression plasmid encoding the largest (8kb) DMBT1 variant (DMBT1+ cells) or an empty vector control (DMBT1- cells) and incubated with ACC both showed significantly reduced DMBT1 concentrations in the culture medium (p = 0.0001). To further elucidate the function of DMBT1 in pulmonary airways, respiratory epithelial cells were examined by phase contrast microscopy. Addition of human recombinant DMBT1 resulted in altered cilia motility and irregular beat waves (p < 0.0001) suggesting a potential effect of DMBT1 on airway clearance.
    CONCLUSIONS: DMBT1 is part of inflammatory processes in CF and may be used as a potential biomarker for CF lung disease and a potential tool to monitor CF progression. Furthermore, DMBT1 has a negative effect on ciliary motility thereby possibly compromising airway clearance. Application of ACC, leading to reduced DMBT1 concentrations, could be a potential therapeutic option for CF patients.
    Keywords:  Acetylcysteine; Ciliary motility; Cystic fibrosis; DMBT1; Inflammation
    DOI:  https://doi.org/10.1186/s40348-022-00136-0
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