scholarly journals Connexin-Based Channel Activity Is Not Specifically Altered by Hepatocarcinogenic Chemicals

2021 ◽  
Vol 22 (21) ◽  
pp. 11724
Author(s):  
Kaat Leroy ◽  
Alanah Pieters ◽  
Axelle Cooreman ◽  
Raf Van Campenhout ◽  
Bruno Cogliati ◽  
...  

Connexin-based channels play key roles in cellular communication and can be affected by deleterious chemicals. In this study, the effects of various genotoxic carcinogenic compounds, non-genotoxic carcinogenic compounds and non-carcinogenic compounds on the expression and functionality of connexin-based channels, both gap junctions and connexin hemichannels, were investigated in human hepatoma HepaRG cell cultures. Expression of connexin26, connexin32, and connexin43 was evaluated by means of real-time reverse transcription quantitative polymerase chain reaction analysis, immunoblot analysis and in situ immunostaining. Gap junction functionality was assessed via a scrape loading/dye transfer assay. Opening of connexin hemichannels was monitored by measuring extracellular release of adenosine triphosphate. It was found that both genotoxic and non-genotoxic carcinogenic compounds negatively affect connexin32 expression. However, no specific effects related to chemical type were observed at gap junction or connexin hemichannel functionality level.

2021 ◽  
Vol 22 (7) ◽  
pp. 3503
Author(s):  
Raf Van Campenhout ◽  
Ana Rita Gomes ◽  
Timo W.M. De Groof ◽  
Serge Muyldermans ◽  
Nick Devoogdt ◽  
...  

Gap junctions and connexin hemichannels mediate intercellular and extracellular communication, respectively. While gap junctions are seen as the “good guys” by controlling homeostasis, connexin hemichannels are considered as the “bad guys”, as their activation is associated with the onset and dissemination of disease. Open connexin hemichannels indeed mediate the transport of messengers between the cytosol and extracellular environment and, by doing so, fuel inflammation and cell death in a plethora of diseases. The present mini-review discusses the mechanisms involved in the activation of connexin hemichannels during pathology.


2021 ◽  
pp. 1358863X2110354
Author(s):  
Saranya Rajendran ◽  
Lakshmikirupa Sundaresan ◽  
Geege Venkatachalam ◽  
Krithika Rajendran ◽  
Jyotirmaya Behera ◽  
...  

Endothelium-derived nitric oxide (NO) is a mediator of angiogenesis. However, NO-mediated regulation of vasculogenesis remains largely unknown. In the present study, we show that the inhibition of NO significantly attenuated endothelial migration, ring formation, and tube formation. The contribution of nitric oxide synthase (NOS) enzymes during early vasculogenesis was assessed by evaluating endothelial NOS (eNOS) and inducible NOS (iNOS) mRNA expression during HH10–HH13 stages of chick embryo development. iNOS but not eNOS was expressed at HH12 and HH13 stages. We hypothesized that vasculogenic events are controlled by NOS-independent reduction of nitrite to NO under hypoxia during the very early phases of development. Semi-quantitative polymerase chain reaction analysis of hypoxia-inducible factor-1α (HIF-1α) showed higher expression at HH10 stage, after which a decrease was observed. This observation was in correlation with the nitrite reductase (NR) activity at HH10 stage. We observed a sodium nitrite-induced increase in NO levels at HH10, reaching a gradual decrease at HH13. The possible involvement of a HIF/NF-κB/iNOS signaling pathway in the process of early vasculogenesis is suggested by the inverse relationship observed between nitrite reduction and NOS activation between HH10 and HH13 stages. Further, we detected that NR-mediated NO production was inhibited by several NR inhibitors at the HH10 stage, whereas the inhibitors eventually became less effective at later stages. These findings suggest that the temporal dynamics of the NO source switches from NR to NOS in the extraembryonic area vasculosa, where both nitrite reduction and NOS activity are defined by hypoxia.


Blood ◽  
2006 ◽  
Vol 108 (4) ◽  
pp. 1223-1229 ◽  
Author(s):  
Dehua Wang ◽  
Jenice D'Costa ◽  
Curt I. Civin ◽  
Alan D. Friedman

Abstract C/EBPα is required for generation of granulocyte-monocyte progenitors, but the subsequent role of C/EBPα in myeloid lineage commitment remains uncertain. We transduced murine marrow cells with C/EBPα-estradiol receptor (ER) or empty vector and subjected these to lineage depletion just prior to culture in estradiol with myeloid cytokines. This protocol limits biases due to lineage-specific effects on developmental kinetics, proliferation, and apoptosis. Also, lowering the dose of estradiol reduced activated C/EBPα-ER to near the physiologic range. C/EBPα-ER increased Mac1+/Gr1–/MPO–/low monocytes 1.9-fold while reducing Mac1+/Gr1+/MPOhi granulocytes 2.5-fold at 48 hours, even in 0.01 μM estradiol. This pattern was confirmed morphologically and by quantitative polymerase chain reaction (PCR) assay of lineage markers. To directly assess effects on immature progenitors, transduced cells were cultured for 1 day with and then in methylcellulose without estradiol. A 2-fold increase in monocytic compared with granulocytic colonies was observed in IL-3/IL-6/SCF or GM-CSF, but not G-CSF, even in 0.01 μM estradiol. C/EBPα-ER induced PU.1 mRNA, and PU.1-ER stimulated monocytic development, suggesting that transcriptional induction of PU.1 by C/EBPα contributes to monopoiesis. A C/EBPα variant incapable of zippering with c-Jun did not induce monopoiesis, and a variant unable to bind NF-κB p50 stimulated granulopoiesis, suggesting their cooperation with C/EBPα during monocytic commitment.


2016 ◽  
Vol 29 (12) ◽  
pp. 990-1003 ◽  
Author(s):  
Hua Li ◽  
Zhanquan Zhang ◽  
Chang He ◽  
Guozheng Qin ◽  
Shiping Tian

The NADPH oxidase (NOX) complex has been shown to play a crucial role in stress response and in the virulence of various fungal pathogens. The underlying molecular mechanisms of NOX, however, remain largely unknown. In the present study, a comparative proteomic analysis compared changes in protein abundance in wild-type Botrytis cinerea and ΔbcnoxR mutants in which the regulatory subunit of NOX was deleted. The ΔbcnoxR mutants exhibited reduced growth, sporulation, and impaired virulence. A total of 60 proteins, representing 49 individual genes, were identified in ΔbcnoxR mutants that exhibited significant differences in abundance relative to wild-type. Reverse transcription-quantitative polymerase chain reaction analysis demonstrated that the differences in transcript levels for 36 of the genes encoding the identified proteins were in agreement with the proteomic analysis, while the remainder exhibited reverse levels. Functional analysis of four proteins that decreased abundance in the ΔbcnoxR mutants indicated that 6-phosphogluconate dehydrogenase (BcPGD) played a role in the growth and sporulation of B. cinerea. The Δbcpgd mutants also displayed impaired virulence on various hosts, such as apple, strawberry, and tomato fruit. These results suggest that NOX can influence the expression of BcPGD, which has an impact on growth, sporulation, and virulence of B. cinerea.


Homeopathy ◽  
2018 ◽  
Vol 108 (01) ◽  
pp. 043-053 ◽  
Author(s):  
José Mazón-Suástegui ◽  
Joan Salas-Leiva ◽  
Andressa Teles ◽  
Dariel Tovar-Ramírez

Background This research aimed to observe the effect of homeopathic treatments prepared from Vibrio parahaemolyticus and V. alginolyticus (H1) and commercial homeopathic medication Phosphoricum acidum and Silicea terra (H2) on the immune and antioxidant response in Seriola rivoliana juveniles under usual culture conditions and challenged with V. parahaemolyticus. Materials and Methods Quantitative polymerase chain reaction analysis was used to study changes in the expression of key genes related to immune response, cytokines (interleukin-1β [IL-1β]), adapter protein for cytokine release (MyD88) and piscidin and spectrophotometric techniques to analyze the activity of antioxidant superoxide dismutase (SOD) and catalase (CAT) enzymes in Seriola rivoliana juveniles at 30 (weaning stage [WS]) and 60 (early juveniles [EJ]) days post-hatching. Results The H1 treatment led to over-expression of the IL-1β and MyD88 genes in fish at WS and EJ with respect to control, contrary to the H2 treatment that led to under-expression of the IL-1β, MyD88 and piscidin genes at the EJ stage. In fish challenged with V. parahaemolyticus, both H1 and H2 led to over-expression of IL-1β and MyD88; H2 caused an over-expression of piscidin. The SOD activity was higher in H1 with respect to H2 and the control group. CAT remained relatively stable with both H1 and H2 treatments. Conclusions The results suggest that the overall effect of H1 was due to the presence of unknown antigens in low concentrations, while the response to H2—specifically during challenge—may have been due to a stimulating effect of nano-structures, prevailing from mother tincture after sequential dilution/succussion, in a pathway similar to that attributed to nano-vaccines.


2018 ◽  
Vol 30 (4) ◽  
pp. 651 ◽  
Author(s):  
Kevin Danastas ◽  
Emily J. Miller ◽  
Alison J. Hey-Cunningham ◽  
Christopher R. Murphy ◽  
Laura A. Lindsay

Angiogenesis is a critical step in the development of ectopic lesions during endometriosis. Although total vascular endothelial growth factor (VEGF) A is elevated in the peritoneal fluid of women with endometriosis, there are contradictory reports on how levels of total endometrial VEGFA are altered in this disease. Furthermore, limited research is available on different VEGFA isoforms in women with endometriosis. Thus, the aim of the present study was to analyse levels of various VEGFA isoforms in women with and without endometriosis at different stages of the menstrual cycle. Quantitative polymerase chain reaction analysis showed that total VEGFA was highest during menstruation in endometriosis compared with controls (P = 0.0373). VEGF121 and VEGF189 were similarly highest during menstruation in endometriosis compared with controls (P = 0.0165 and 0.0154 respectively). The present study is also the first to identify the natural expression of VEGF111 in human tissue, which is also highest during menstruation in endometriosis (P = 0.0464). This discovery of the natural production of VEGF111 in human endometrium, as well as the upregulation of VEGFA isoforms during menstruation in endometriosis, may shed further light on the development and progression of the disease, and improve our understanding of the regulation of endometrial angiogenesis.


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