Cell Biological Changes Research Articles

AT1b receptors contribute to regional disparities in angiotensin II mediated aortic remodelling in mice.

The renin-angiotensin system plays a key role in regulating blood pressure, which has motivated many investigations of associated mouse models of hypertensive arterial remodelling. Such studies typically focus on histological and cell biological changes, not wall mechanics. This study explores tissue-level ramifications of chronic angiotensin II infusion in wild-type (WT) and type 1b angiotensin II (AngII) receptor null (Agtr1b -/-) mice. Biaxial biomechanical and immunohistological changes were quantified and compared in the thoracic and abdominal aorta in these mice following 14 and 28 days of angiotensin II infusion. Preliminary results showed that changes were largely independent of sex. Associated thickening and stiffening of the aortic wall in male mice differed significantly between thoracic and abdominal regions and between genotypes. Notwithstanding multiple biomechanical changes in both WT and Agtr1b -/- mice, AngII infusion caused distinctive wall thickening and inflammation in the descending thoracic aorta of WT, but not Agtr1b -/-, mice. Our study underscores the importance of exploring differential roles of receptor-dependent angiotensin II signalling along the aorta and its influence on distinct cell types involved in regional histomechanical remodelling. Disrupting the AT1b receptor primarily affected inflammatory cell responses and smooth muscle contractility, suggesting potential therapeutic targets.

Micropeptide AF127577.4-ORF hidden in a lncRNA diminishes glioblastoma cell proliferation via the modulation of ERK2/METTL3 interaction.

Micropeptides hidden in long non-coding RNAs (lncRNAs) have been uncovered to program various cell-biological changes associated with malignant transformation-glioblastoma (GBM) cascade. Here, we identified and characterized a novel hidden micropeptide implicated in GBM. We screened potential candidate lncRNAs by establishing a workflow involving ribosome-bound lncRNAs, publicly available MS/MS data, and prognosis-related lncRNAs. Micropeptide expression was detected by western blot (WB), immunofluorescence (IF), and immunohistochemistry (IHC). Cell proliferation rate was assessed by calcein/PI staining and EdU assay. Proteins interacted with the micropeptide were analyzed by proteomics after co-immunoprecipitation (Co-IP). We discovered that lncRNA AF127577.4 indeed encoded an endogenous micropeptide, named AF127577.4-ORF. AF127577.4-ORF was associated with GBM clinical grade. In vitro, AF127577.4-ORF could suppress GBM cell proliferation. Moreover, AF127577.4-ORF reduced m6A methylation level of GBM cells. Mechanistically, AF127577.4-ORF diminished ERK2 interaction with m6A reader methyltransferase like 3 (METTL3) and downregulated phosphorylated ERK (p-ERK) level. The ERK inhibitor reduced p-ERK level and downregulated METTL3 protein expression. AF127577.4-ORF weakened the stability of METTL3 protein by ERK. Also, AF127577.4-ORF suppressed GBM cell proliferation via METTL3. Our study identifies a novel micropeptide AF127577.4-ORF hidden in a lncRNA, with a potent anti-proliferating function in GBM by diminishing METTL3 protein stability by reducing the ERK2/METTL3 interaction. This micropeptide may be beneficial for development of therapeutic strategies against GBM.

The effects of SARS-CoV-2 on susceptible human cells

The biological consequences of viral infection result from biochemical, physiological, structural, morphological and genetic changes in infected cells. In productive infections, virus-induced biological changes in cells may be closely related to the efficiency of viral replication or to the recognition of these cells by the immune system. These changes are usually associated with cytocidal viruses, as in the case of the pandemic coronavirus SARS-CoV-2, which causes COVID-19. Many of these changes are required for effective viral replication. The physiological state of living cells has a significant impact on the outcome of viral infection, as the host cell provides the synthetic machinery, key regulatory molecules and precursors for newly synthesised viral proteins and nucleic acids. This review focuses on novel target cell types for SARS-CoV-2 exposure outside the respiratory tract. Findings and examples are collected that provide information on virus-cell interactions. The identification of unusual target cells for SARS-CoV-2 may help to explain the diverse symptoms in COVID-19 patients and the long-lasting effects after infection. In particular, the discovery of previously undescribed target cells for SARS-CoV-2 action needs to be considered to improve treatment of patients and prevention of infection.

Abstract 350: High-dimensional Analysis Of Circulating Blood Cells Reveals Distinct Granulocyte Activation And NETosis Profiles In COVID-19

Background: Coronavirus disease 19 (COVID-19) represents a perfect storm for immunothrombosis leading to severe disease, with release of neutrophil extracellular traps (NETs) being an important contributor now frequently described both in blood and in tissues. NETs contribute to thrombosis by trapping platelets and activating the coagulation cascade, as well as endotheliopathy. NET formation is an active process initiated by factors such as activated platelets and involving histone modifications including citrullination. Aims: We aimed to characterize early activation toward NETosis in circulating granulocytes in the context of neutrophil activation, immunothrombosis, and the broader immune response in COVID-19, particularly in severe disease involving ICU stays. Methods: We designed a custom panel of 42 antibodies to stain peripheral blood collected from COVID-19 patients in ICU at UZ Leuven during the COVID-19 Delta-wave. This panel comprised cell-specific epitopes, surface activation markers, intracellular staining for NET-associated cell biological changes, and platelet markers to identify complexes. Samples were run using cytometry by time-of-flight (CyTOF) on a Helios mass cytometer and analyzed using FlowJo software with FlowSOM clustering and tSNE visualisation. Results: Nonbiased clustering analysis was performed and identified 18 distinct populations of granulocytes. Four of these populations were present only in COVID-19 patients, with high expression of CD11b, CD177, and CD16. A distinct population of citrullinated histone-positive eosinophils was also identified in COVID-19 patients, with higher expression than any of the neutrophil populations. Ex vivo stimulation of healthy donor granulocytes toward NETosis shifted the expression profile toward that of COVID-19 patient granulocytes. However, morphometric analysis using scatterbody targets failed to identify cell biological changes common to NET formation. Conclusions: High dimensional profiling of circulating blood cells identifies distinct granulocyte populations with activation profiles in COVID-19, highlighting the heterogeneity of neutrophil responses and involvement of eosinophils in extracellular trap release.

Correction to: Tramadol Biological Effects: 4: Effective Therapeutic Efficacy of Lagenaria siceraria Preparation (Gamal & Aref1) and Melatonin on Cell Biological, Histochemical, and Histopathological Changes in the Kidney of Tramadol-Induced Male Mice.

Correction to: Tramadol Biological Effects: 4: Effective Therapeutic Efficacy of Lagenaria siceraria Preparation (Gamal & Aref1) and Melatonin on Cell Biological, Histochemical, and Histopathological Changes in the Kidney of Tramadol-Induced Male Mice.

Modeling cell biological features of meiotic chromosome pairing to study interlock resolution.

During meiosis, homologous chromosomes become associated side by side in a process known as homologous chromosome pairing. Pairing requires long range chromosome motion through a nucleus that is full of other chromosomes. It remains unclear how the cell manages to align each pair of chromosomes quickly while mitigating and resolving interlocks. Here, we use a coarse-grained molecular dynamics model to investigate how specific features of meiosis, including motor-driven telomere motion, nuclear envelope interactions, and increased nuclear size, affect the rate of pairing and the mitigation/resolution of interlocks. By creating in silico versions of three yeast strains and comparing the results of our model to experimental data, we find that a more distributed placement of pairing sites along the chromosome is necessary to replicate experimental findings. Active motion of the telomeric ends speeds up pairing only if binding sites are spread along the chromosome length. Adding a meiotic bouquet significantly speeds up pairing but does not significantly change the number of interlocks. An increase in nuclear size slows down pairing while greatly reducing the number of interlocks. Interestingly, active forces increase the number of interlocks, which raises the question: How do these interlocks resolve? Our model gives us detailed movies of interlock resolution events which we then analyze to build a step-by-step recipe for interlock resolution. In our model, interlocks must first translocate to the ends, where they are held in a quasi-stable state by a large number of paired sites on one side. To completely resolve an interlock, the telomeres of the involved chromosomes must come in close proximity so that the cooperativity of pairing coupled with random motion causes the telomeres to unwind. Together our results indicate that computational modeling of homolog pairing provides insight into the specific cell biological changes that occur during meiosis.

Tramadol Biological Effects, 2: Effective Therapeutic Efficacy of Lagenaria siceraria Preparation and Melatonin on Cell Biological, Histochemical and Histopathological Changes in Hepatocytes of Tramadol-Induced Male Mice

Tramadol Biological Effects, 2: Effective Therapeutic Efficacy of Lagenaria siceraria Preparation and Melatonin on Cell Biological, Histochemical and Histopathological Changes in Hepatocytes of Tramadol-Induced Male Mice

Immortalized striatal precursor neurons from Huntington's disease patient-derived iPS cells as a platform for target identification and screening for experimental therapeutics.

We have previously established induced pluripotent stem cell (iPSC) models of Huntington's disease (HD), demonstrating CAG-repeat-expansion-dependent cell biological changes and toxicity. However, the current differentiation protocols are cumbersome and time consuming, making preparation of large quantities of cells for biochemical or screening assays difficult. Here, we report the generation of immortalized striatal precursor neurons (ISPNs) with normal (33) and expanded (180) CAG repeats from HD iPSCs, differentiated to a phenotype resembling medium spiny neurons (MSN), as a proof of principle for a more tractable patient-derived cell model. For immortalization, we used co-expression of the enzymatic component of telomerase hTERT and conditional expression of c-Myc. ISPNs can be propagated as stable adherent cell lines, and rapidly differentiated into highly homogeneous MSN-like cultures within 2 weeks, as demonstrated by immunocytochemical criteria. Differentiated ISPNs recapitulate major HD-related phenotypes of the parental iPSC model, including brain-derived neurotrophic factor (BDNF)-withdrawal-induced cell death that can be rescued by small molecules previously validated in the parental iPSC model. Proteome and RNA-seq analyses demonstrate separation of HD versus control samples by principal component analysis. We identified several networks, pathways, and upstream regulators, also found altered in HD iPSCs, other HD models, and HD patient samples. HD ISPN lines may be useful for studying HD-related cellular pathogenesis, and for use as a platform for HD target identification and screening experimental therapeutics. The described approach for generation of ISPNs from differentiated patient-derived iPSCs could be applied to a larger allelic series of HD cell lines, and to comparable modeling of other genetic disorders.

Possible Short-Term Biological Effects of Kefir Beverage: Ⅰ: Effect of Kefir Beverage on The Cell Biological, Histochemical, Histopathological and Biochemical Changes in Pancreas of High Fat-Fed STZ- Induced Diabetic Male Wistar Rat

The present study was designed to investigate the biological effects of kefir and whether kefir consumption protects and/or repairs the pancreas of high-fat diet-fed streptozotocin-diabetic rats, and how does it do that?. Our results showed Kefir decreased both the volume of nuclei and RNA content and increased both collagen and lipoproteins material contents in the normal pancreatic cells. Also, kefir increased RNA, protein, and lipoproteins materials content and decreased the volume of nuclei of pancreatic cells in diabetic male rats. Immunohistochemically, kefir showed highly immunoreactive signals of insulin granules inside the Langerhans Islands. Our results showed kefir consumption had a beneficial effect on controlling the glycemic state in diabetic rats by lowering insulin levels and kept the pancreas tissue structurally almost normal. Kefir probably acts as follows: From the cell biological and histochemical points of view, the results showed an increase in the nuclei volume and DNA, RNA, and total protein contents in the pancreatic cells of diabetic rats treated with kefir. Also, the biochemical and immunohistochemical results showed an increase in insulin hormone (functional protein) of these pancreatic cells, which’s probably a result of an increase in the cellular activities or/and the number of beta cells. Finally, therefore we propose that kefir has a stimulatory effect on the cellular activity of beta cells leading to activation of genes responsible for the protein synthesis included insulin hormone, and/or increasing the cell proliferation of beta cells in the pancreas of diabetic rats. From Cell biological, Histochemical, Immunohistochemical, pathological, and Biochemical points of view, the preclinical treatment with kefir or insulin of normal or diabetic male rats, beneficially highly alternates the cellular activities, histochemical and immunohistochemical materials components, and histological architecture. of the pancreas therefore Kefir and insulin may, to some extent, repair the pathological side effects of type 1 diabetes mellitus. The positive results of using kefir and insulin in treating the Pathogen effects of type 1 diabetes mellitus on the pancreas of male mice gave us a hope of possibility to obtain positive clinical applications/implications. Therefore, these positive beneficial results make us continue our work and complete the various pre-clinical trial and clinical experiments phases.

Possible Short-Term Biological Effects of Kefir: Ⅱ: Protective Role and Therapeutic Efficacy of Kefir Beverage on The Cell Biological, Histochemical, Histopathological and Biochemical Changes in Liver of High-Fat-Fed STZ- Induced Diabetic Male Wistar Rat

This study was designed to investigate the protective role of kefir and insulin consumption on cellular activities, histochemical components, histological architecture, and integrity of the liver by measuring IL-6 and TNF-α in high fat-fed STZ- induced diabetic male Wistar rats. From a cell biological and histochemical point of view, both kefir and insulin have beneficial various effects on cellular activities and the histochemical components such as DNA, RNA, total protein, collagen, polysaccharides, and phospholipids materials synthesis in the examined normal and diabetic hepatocytes of the male rats. Biochemically, kefir and insulin have various biochemical effects on the serum IL-6 and TNF-α levels. From a pathological point of view, we can say the beneficial various cell biological and histochemical effects of kefir, pathologically may make kefir, to some extent, completely repair all the pathological side effects of type1 diabetes on the hepatocytes in diabetic rats. Also, insulin repair some of the pathological side effects of diabetes on the hepatocytes. The positive results of using kefir and insulin in treating the pathogen effects of diabetes make it possible to obtain positive clinical applications/implications. Therefore, these positive results encourage us to continue working and complete the various long-term pre-clinical trials and clinical trials phases.

Possible Short-Term Biological Effects of Kefir: ⅡⅠ: Efficacy of Kefir Beverage on The Cell Biological, Histochemical, Histopathological and Biochemical Changes in Kidney of High-Fat Fed STZ- Induced Diabetic Male Wistar Rat.

This study was designed to investigate the possible protective role of kefir beverage on kidney structure biologically, histochemical and some biochemical parameters such as cholesterol level, MCP-1, and resistin in high-fat diet-fed streptozotocin-diabetic rats. 60 rats were divided into two experiments by six groups: experiment Ⅰ included 3 non-diabetic ones and experiment ⅠⅠ included three STZ- induced diabetes groups. The groups were fed as follows: group 1 received a standard diet and served as control. Group 2 was fed on a standard diet and kefir (0.7 ml/animal/day by gavage). Group 3 received a high-fat diet and kefir (0.7 ml/animal/day by gavage). The diabetic males of groups A, B, and C were fed on the high-fat diet. Group B received besides kefir (0.7 ml/animal/day by gavage), while group C was injected additionally with insulin (0.76 UI/200 mg BW/day). After 5 weeks, animals of all groups were sacrificed. From the cell biological, histochemical, and histopathological conceptions, both kefir and insulin have various effects on cellular activities and different chemical materials contents, such as DNA, RNA, total protein, collagen, polysaccharides, and lipoproteins, in the examined normal and diabetic renal tubule cells of the male rats. Overall, it seems like kefir beverage may, to some extent, completely repair the diabetic pathological side effects such as kidney dysfunction regarding keeping the kidney tissue structurally almost normal with some changes in the histochemical components investigated, also there was an improvement in cholesterol level with a beneficial effect on lowering inflammatory markers. Finally, kefir highly reduces the collagen formation in the renal cells that prevent renal nephron from its function and we propose probably kefir treats kidney failure as a side effect of diabetes, by a mechanism that is opposite to the proposed mechanism, for the formation of this kidney failure induced by diabetes, via us in the present work.

Effect of BRAF-mediated PI3K/Akt/mTOR pathway on biological characteristics and chemosensitivity of NSCLC A549/DDP cells.

The present study aimed to explore the biological characteristics of non-small cell lung cancer (NSCLC) cells and the mechanism of chemosensitivity through the role of the PI3K/Akt/mTOR signaling pathway mediated by BRAF gene silencing. Following cell transfection and grouping, an MTT assay detected the activity of NSCLC cells, a scratch wound test assessed the migration ability, flow cytometry using PI staining detected the cell cycle phase, TUNEL and flow cytometry through Annexin V-PI staining assessed the apoptosis, and colony formation was used to detect the sensitivity of lung cancer cells to cisplatin chemotherapy. Furthermore, the relative expression levels of BRAF, PTEN, PI3K, mTOR mRNA were assessed by RT-qPCR, and the protein expression levels of BRAF, PTEN, PI3K, phosphorylated (p)-PI3K, Akt, p-Akt, mTOR, p-mTOR, cisplatin resistance-related enzymes ERCC1 and BRCA1, apoptotic proteins Bax and Bcl-2 were assessed by western blotting. Compared with the control group and NC group, there were differences in decreased BRAF mRNA expression levels in the small interfering (si)BRAF group and siBRAF + IGF-1 group (both P<0.05). In addition, compared with the control group, the siBRAF, NVP-BEZ235 and siBRAF + NVP-BEZ235 groups had significant decreased cell viability at 2–6 days, decreased migration ability, shortened proportion of S-phase cells, increased proportion of G1/G0-phase cells, increased apoptosis rate, decreased number of colony-forming cells, decreased mRNA expression of PI3K, Akt and mTOR, increased PTEN mRNA expression, decreased protein expression levels of PI3K, p-PI3K, Akt, p-Akt, mTOR, p-mTOR, ERCC1, BRCA1 and Bcl-2, and increased protein expression levels of PTEN and Bax (all P<0.05); and more obvious trends were revealed in the siBRAF + NVP-BEZ235 group (all P<0.05); whereas opposite results were detected in the siBRAF + IGF-1 group when compared with the siBRAF group and NVP-BEZ235 group (all P<0.05). Silencing of BRAF gene expression to inhibit the activation of the PI3K/Akt/mTOR signaling pathway exerted a synergistic effect decreasing cell viability, inhibiting the cell cycle and migration, increasing the apoptosis rate, decreasing the number of colony-forming cells and increasing chemosensitivity of NSCLC. Activation of the PI3K/Akt/mTOR signaling pathway may reverse the role of silencing of BRAF gene expression, providing a potential approach for improving the chemosensitivity of NSCLC. The present study for the first time, to the best of our knowledge, clarified the possible mechanism of NSCLC cell biological characteristic changes and chemosensitivity from the perspective of BRAF gene silencing and PI3K/Akt/mTOR signaling pathway activation, providing a potential reference for suppressing tumor aggravation and improving the therapeutic outcomes of NSCLC at the genetic level.

Autophagy and multivesicular body formation in blastocysts during the experimental diapause in mice

In experimentally induced diapause model in mice, blastocysts remain dormant for an extended period but resume implantation competency upon estrogen injection. The underlying mechanism by which extended longevity of dormant blastocysts is maintained is unclear. We have previously shown that dormant blastocysts, during experimentally induced diapause, exhibit heightened autophagic activation. Activation of autophagy appears to be a crucial adaptive response for survival in the unfavorable uterine environment, as inhibiting autophagy reduces the survival rate of dormant blastocysts. As a unique cell biological change occurring following estrogen supplementation to activate dormant blastocysts, multivesicular bodies (MVBs) accumulate in the trophectoderm. In various cellular contexts, autophagy and MVB formation are linked cell biological phenomena. Herein, we discuss the implications of these cell biological changes in dormant and activated blastocysts.

Correlation of Nucleostemin with Programmed Death-ligand-1 in Multiple Myeloma U266 Cells

To investigate the correlation of nucleostemin (NS) gene with programmed death ligand-1 (PD-L1) in myeloma cells and the effect of NS expression down-regulation on the apoptosis of multiple myeloma cells, and to evaluate the associations among NS, PD-L1 and biological behavior of MM cells, and the feasibility of both NS and PD-1 as markers reflecting the status of MM cells. The NS gene expression in U266 cells was down-regulated by NS-RNAi-GV248 recombinant lentivirus, the real-time PCR was used to detect the mRNA expression of NS, PD-L1 and PI3K/AKT/mTOR. The Western blot and flow cytometry were used to detect the expression of NS and PD-L1. The Annexin V-APC/7-AAD staining method was used to detect the apoptosis of U266 cells before and after knocking out the NS gene. Under the condition of MOI=10, the transfection efficiency was more than 75% by means of the fluorescent microscopy; real-time PCR showed that compared with the negative control group (1.002±0.026), the mRNA expression of NS, PD-L1 and PI3K/AKT/mTOR gene in the transfection group (0.415±0.089) was significantly reduced (P＜0.05). The results of flow cytometry and Western blot showed that the protein expression of PD-L1 was significantly down-regulated after transfection. After down-regulation of NS gene expression, the apoptosis of U266 cells increased (P＜0.05). The abnormal high expression of NS and PD-L1 genes exists in U266 cells, moreover, the down-regulation of PD-L1 and the related PISK/AKT/mTOR pathway gene expression appears after down-regulation of NS gene expression, which suggest that the cell biological changes resulted from above-mentioned results, show a synergestic effect on U266 cells.

Cell biology and mechanopathology of laminopathic cardiomyopathies.

Miroshnikova, Hammesfahr, and Wickström illustrate the complex cell biological changes observed in cells of patients with Lamin A/C cardiomyopathies.

Proteomic Profiling for Target Identification of Biologically Active Small Molecules Using 2D DIGE.

Recent improvements in technologies such as omics analysis have enabled us to acquire a large amount of data regarding the biological changes in cells treated with bioactive small molecules. Using such data, a variety of profiling methods have been established for target identification of such bioactive compounds. In this chapter, we describe a proteomic profiling system, ChemProteoBase, based on proteome analysis using two-dimensional difference gel electrophoresis. This system compares the similarities in protein expression of 296 spots detected in the gel among the test compounds.

Key features of the nephrogenic zone in the fetal human kidney-hardly known but relevant for the detection of first traces impairing nephrogenesis.

In healthy newborn babies, nephrogenesis proceeds unnoticed until birth. With start of the perinatal period, morphogenetic activity in the renal outer cortex consisting of an inner maturation zone and an outer nephrogenic zone is downregulated by unknown signals. One of the results is that the entire nephrogenic zone as well as the contained progenitor cells and niches disintegrate. In contrast, a too early inactivation of the nephrogenic zone takes place in the kidneys of preterm and low birth weight babies. Although they are born in a period of active nephrogenesis, pathological findings show that they evolve to a high incidence oligonephropathy. However, very few data exist about cell biological changes that are evoked by harming, further most of causing molecules, exact cell targets, and related molecular pathways are not identified. Although impairment of nephrogenesis was the subject of research in animal species, there is only limited information available pertaining to the pathological traces in the nephrogenic zone of the human fetal kidney. In this situation, the lack of basic morphological data is particularly aggravating. Surprisingly, there are not even ultrastructural investigations available. Since concrete information is lacking also in relevant textbooks, the current contribution likes to present key features of the nephrogenic zone in the fetal human kidney. Simultaneously, it is a call to explore systematically a hardly known area.

See brain cancer as more than just the sum of biology.

Neurological symptoms, as well as biological changes in cells and tissues, contribute to the disease’s characteristics, says Terri S. Armstrong. Neurological symptoms, as well as biological changes in cells and tissues, contribute to the disease’s characteristics, says Terri S. Armstrong.

Tramadol Biological Effects: Ⅰ: Effective Therapeutic Efficacy of Lagenaria siceraria Preparation (Gamal &amp; Aref1) and Melatonin on Cell Biological, Histochemical and histopathological Changes in Ileum of Tramadol-Induced Male Mice

Tramadol is used worldwide and is listed in many medical guidelines to treat both acute and chronic pain. There is growing evidence of abuse of tramadol in some African and West Asian countries. Tramadol has some side effects. The present study was designed a follow-up and treatment of the cell biological, histochemical and Pathological response which might be induced in the ileum of tramadol application. A total number of 70 adult males Swiss albino mice were obtained and survived during experiments from/in (Autoradiographic lab. of Cell Biology and Immunology studies, Faculty of Science, South Valley University), under supervision Dr. Abdel-baset Aref Mohamed. At the time of the experiments, the mice were aged 90 ± 5 days and weighed 30 ± 2 g. All male mice were kept under the same conditions of light-dark cycle (12h-12h), temperature (23 ± 2oc), and humidity (37-40%). They were supplied standard food and water ad libitum. The daily injections of tramadol for 20 reach to 40 days highly changed the volume of nuclei and protein, RNA and DNA materials contained in the cells lining ileum, therefore, extensively and severely destructions showed in the normal histological architecture of ileum of male mice. Finally, we could say, Although, tramadol has many cytological, histochemical and histopathological, side effects on ileum of male mice but the treatments with Lagenaria siceraria and melatonin have a more effective therapeutic effect on tramadol side effects.

Ectopic expression of aquaporin-5 in noncancerous epithelial MDCK cells changes cellular morphology and actin fiber formation without inducing epithelial-to-mesenchymal transition.

Aquaporin-5 (AQP5) is a plasma membrane water channel mainly expressed in secretory glands. Increased expression of AQP5 is observed in multiple cancers, including breast cancer, where high expression correlates with the degree of metastasis and poor prognosis. Moreover, studies in cancer cells have suggested that AQP5 activates Ras signaling, drives morphological changes, and in particular increased invasiveness. To design intervention strategies, it is of utmost importance to characterize and dissect the cell biological changes induced by altered AQP5 expression. To isolate the effect of AQP5 overexpression from the cancer background, AQP5 was overexpressed in normal epithelial MDCK cells which have no endogenous AQP5 expression. AQP5 overexpression promoted actin stress fiber formation and lamellipodia dynamics. Moreover, AQP5 decreased cell circularity. Phosphorylation of AQP5 on serine 156 in the second intracellular loop has been shown to activate the Ras pathway. When serine 156 was mutated to alanine to mimic the nonphosphorylated state, the decrease in cell circularity was reversed, indicating that the AQP5-Ras axis is involved in the effect on cell shape. Interestingly, the cellular changes mediated by AQP5 were not associated with induction of epithelial-to-mesenchymal transition. Thus, AQP5 may contribute to cancer by altering cellular morphology and actin organization, which increase the metastatic potential.