DSpace Repository :: Browsing by Author "González, Carlos"

Browsing by Author "González, Carlos"

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A physiological approach to understand the role of respiratory effort in the progression of lung injury in SARS-CoV-2 infection
(2020) Cruces, Pablo; Retamal, Jaime; Hurtado, Daniel E.; Erranz, Benjamín; Iturrieta, Pablo; González, Carlos; Díaz, Franco
Deterioration of lung function during the first week of COVID-19 has been observed when patients remain with insufficient respiratory support. Patient self-inflicted lung injury (P-SILI) is theorized as the responsible, but there is not robust experimental and clinical data to support it. Given the limited understanding of P-SILI, we describe the physiological basis of P-SILI and we show experimental data to comprehend the role of regional strain and heterogeneity in lung injury due to increased work of breathing. In addition, we discuss the current approach to respiratory support for COVID-19 under this point of view
Carbon monoxide: A new player in the redox regulation of connexin hemichannels
(International Union of Biochemistry and Molecular Biology, 2015) Retamal, Mauricio; León-Paravic, Carmen; Ezquer, Marcelo; Ezquer, Fernando; Del Río, Rodrigo; Pupo, Amaury; Martínez, Agustín; González, Carlos
Carbon monoxide (CO) is a gaseous transmitter that is known to be involved in several physiological processes, but surprisingly it is also becoming a promising molecule to treat several pathologies including stroke and cancer. CO can cross the plasma membrane and activate guanylate cyclase, increasing the cGMP concentration and activating some kinases, including PKG. The other mechanism of action involves induction of protein carbonylation. CO is known to directly and indirectly modulate the function of ion channels at the plasma membrane, which in turn have important repercussions in the cellular behavior. One group of these channels is hemichannels, which are formed by proteins known as connexins (Cxs). Hemichannel allows not only the flow of ions through their pore but also the release of molecules such as ATP and glutamate. Therefore, their modulation not only impacts cellular function but also cellular communication, having the capability to affect tissular behavior. Here, we review the most recent results regarding the effect of CO on Cx hemichannels and their possible repercussions on pathologies.
Charged Residues at the First Transmembrane Region Contribute to the Voltage Dependence of the Slow Gate of Connexins
(American Society for Biochemistry and Molecular Biology by Sage, 2016) Pinto, Bernardo; García, Isaac; Pupo, Amaury; Retamal, Mauricio; Martínez, Agustín; Latorre, Ramón; González, Carlos
Connexins (Cxs) are a family of membrane-spanning proteins that form gap junction channels and hemichannels. Connexin-based channels exhibit two distinct voltage-dependent gating mechanisms termed slow and fast gating. Residues located at the C terminus of the first transmembrane segment (TM-1) are important structural components of the slow gate. Here, we determined the role of the charged residues at the end of TM-1 in voltage sensing in Cx26, Cx46, and Cx50. Conductance/voltage curves obtained from tail currents together with kinetics analysis reveal that the fast and slow gates of Cx26 involves the movement of two and four charges across the electric field, respectively. Primary sequence alignment of different Cxs shows the presence of well conserved glutamate residues in the C terminus of TM-1; only Cx26 contains a lysine in that position (lysine 41). Neutralization of lysine 41 in Cx26 increases the voltage dependence of the slow gate. Swapping of lysine 41 with glutamate 42 maintains the voltage dependence. In Cx46, neutralization of negative charges or addition of a positive charge in the Cx26 equivalent region reduced the slow gate voltage dependence. In Cx50, the addition of a glutamate in the same region decreased the voltage dependence, and the neutralization of a negative charge increased it. These results indicate that the charges at the end of TM-1 are part of the slow gate voltage sensor in Cxs. The fact that Cx42, which has no charge in this region, still presents voltage-dependent slow gating suggests that charges still unidentified also contribute to the slow gate voltage sensitivity.
Connexinopathies: a structural and functional glimpse
(2016) García, Isaac E; Prado, Pavel; Pupo, Amaury; Jara, Oscar; Rojas-Gómez, Diana; Mujica, Paula; Flores-Muñoz, Carolina; González-Casanova, Jorge; Soto-Riveros, Carolina; Pinto, Bernardo I; Retamal, Mauricio A.; González, Carlos; Martínez, Agustín D
Mutations in human connexin (Cx) genes have been related to diseases, which we termed connexinopathies. Such hereditary disorders include nonsyndromic or syndromic deafness (Cx26, Cx30), Charcot Marie Tooth disease (Cx32), occulodentodigital dysplasia and cardiopathies (Cx43), and cataracts (Cx46, Cx50). Despite the clinical phenotypes of connexinopathies have been well documented, their pathogenic molecular determinants remain elusive. The purpose of this work is to identify common/uncommon patterns in channels function among Cx mutations linked to human diseases. To this end, we compiled and discussed the effect of mutations associated to Cx26, Cx32, Cx43, and Cx50 over gap junction channels and hemichannels, highlighting the function of the structural channel domains in which mutations are located and their possible role affecting oligomerization, gating and perm/ selectivity processes.
Extracellular Cysteine in Connexins: Role as Redox Sensors
(Lausanne : Frontiers Research Foundation, 2016) Retamal, Mauricio; García, Isaac; Pinto, Bernardo; Pupo, Amaury; Báez, David; Stehberg, Jimmy; Del Río, Rodrigo; González, Carlos
Connexin-based channels comprise hemichannels and gap junction channels. The opening of hemichannels allow for the flux of ions and molecules from the extracellular space into the cell and vice versa. Similarly, the opening of gap junction channels permits the diffusional exchange of ions and molecules between the cytoplasm and contacting cells. The controlled opening of hemichannels has been associated with several physiological cellular processes; thereby unregulated hemichannel activity may induce loss of cellular homeostasis and cell death. Hemichannel activity can be regulated through several mechanisms, such as phosphorylation, divalent cations and changes in membrane potential. Additionally, it was recently postulated that redox molecules could modify hemichannels properties in vitro. However, the molecular mechanism by which redox molecules interact with hemichannels is poorly understood. In this work, we discuss the current knowledge on connexin redox regulation and we propose the hypothesis that extracellular cysteines could be important for sensing changes in redox potential. Future studies on this topic will offer new insight into hemichannel function, thereby expanding the understanding of the contribution of hemichannels to disease progression.
Pannexin-1 expression in tumor cells correlates with colon cancer progression and survival
(2024) Fierro, Aaron; Landskron, Glauben; Camhi, Ilan; Basterrechea, Benjamín; Parada, Daniela; Lobos-González, Lorena; Dubois, Karen; Araneda, Catalina; Romero, Camila; Domínguez, Antonia; Vásquez, Gonzalo; López, Francisco; Alvarez, Karin; González, Carlos; Hager, Carolina; Balboa, Elisa; Eugenin, Eliseo; Hermoso, Marcela; De la Fuente, Marjorie
Aims: Pannexin-1 (PANX1) is a hemichannel that releases ATP upon opening, initiating inflammation, cell proliferation, and migration. However, the role of PANX1 channels in colon cancer remains poorly understood, thus constituting the focus of this study. Main methods: PANX1 mRNA expression was analyzed using multiple cancer databases. PANX1 protein expression and distribution were evaluated by immunohistochemistry on primary tumor tissue and non-tumor colonic mucosa from colon cancer patients. PANX1 inhibitors (probenecid or 10Panx) were used to assess colon cancer cell lines viability. To study the role of PANX1 in vivo, a subcutaneous xenograft model using HCT116 cells was performed in BALB/c NOD/SCID immunodeficient mice to evaluate tumor growth under PANX1 inhibition using probenecid. Key findings: PANX1 mRNA was upregulated in colon cancer tissue compared to non-tumor colonic mucosa. Elevated PANX1 mRNA expression in tumors correlated with worse disease-free survival. PANX1 protein abundance was increased on tumor cells compared to epithelial cells in paired samples, in a cancer stage-dependent manner. In vitro and in vivo experiments indicated that blocking PANX1 reduced cell viability and tumor growth. Significance: PANX1 can be used as a biomarker of colon cancer progression and blocking PANX1 channel opening could be used as a potential therapeutic strategy against this disease.

Browsing by Author "González, Carlos"

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