Recent events

Seminars

Type of Event:
Speaker: M.Sc. Iqra Yaseen
Day: 2023-07-17, at 12:00:00 hrs.
Place: via teams
Title: SYNTHESIS, CHARACTERIZATION, AND COMPARATIVE PHARMACOLOGICAL ANALYSIS OF SILVER AND COPPER NANOPARTICLES FROM LEAF EXTRACT OF EUCALYPTUS GLOBULUS
Abstract:

The present study is aimed to synthesize silver and copper nanoparticles through a green approach using the leaves of Eucalyptus globules (Myrtaceae) to assess the pharmacological activity of the plant. By using leaf extract silver and copper nanoparticles were synthesized. The dark brown color change was observed in the case of silver nanoparticles which confirmed the formation of AgNPswhereas copper nanoparticle formation was observed light green. The synthesized silver and copper nanoparticles were characterized through SEM, UV, and EDX. To check the antimicrobial activity of different microbial strains were taken i.e. E.coli, P.aeruginosa, and A.flavus. Muller Hinton agar was prepared for culturing bacteria similarly PDA was prepared for fungal growth. For microbial analysis Disc diffusion method was used in this method disc of different concentrations of copper and silver nanoparticles were taken whereas a positive control of different drugs for bacterial and fungal strains was used i.e. Ciprofloxacin for E.coli and fluoroquinolones for P.aeruginosa. For fungus i.e. A. flavus positive control was fluconazole and methanol was the negative control. After the incubation period zone of inhibition was taken. MIC values were taken on the spectrophotometer. For antioxidant activity, different concentrations of silver and copper nanoparticles or ascorbic acid were taken. The spectrophotometer was used for taking readings. DPPH was used for measuring the antioxidant potential of copper and silver nanoparticles. Which showed that copper is more antioxidant than silver nanoparticles. Silver nanoparticles showed more antibacterial activity than copper. E.coli is found to be more resistant. Copper showed more antifungal activity as compared to silver nanoparticles.

Type of Event: Evaluation Examination
Speaker: M.Sc. Mario Alejandro Aguilar Chaparro
Day: 2023-07-27, at 12:00:00 hrs.
Place: Closed door with Teachers College & committee in the Cell Biology´s seminar classroom, vía TEAMS to the rest of the department
Title: CD44std and CD44v9 subpopulations show differential features of cancer stem cells and their participation in TGF-β-induced changes
Abstract:

In hepatocellular carcinoma (HCC), CD44 isoforms have been proposed as potential markers to identify cancer stem cells (CSCs). A distinguishing characteristic of CSCs is undergoing an epithelial-mesenchymal transition (EMT), which can be induced by transforming growth factor-beta (TGF-β). However, the CSC traits in relation to CD44 isoforms and the effects of TGF-β on CSC traits in subpopulations expressing CD44 isoforms in HCC have not been fully defined. The aim of this study was to determine the CSC traits in cells expressing CD44 isoforms and analyze their changes induced by TGF-β. Transcriptomic data analysis in HCC patients identified CD44v8-10 as a potential marker for HCC. In SNU-423 cells, CD44 expression was detected in 99% of the population, and two CD44 isoforms, CD44std and CD44v9, were identified. CD44 subpopulations, CD44v9+ (CD44v9) and CD44v9- (CD44std) cells, were obtained through magnetic bead purification. CD44v9 cells exhibited a higher potential for colony formation, sphere formation, and adhesion, while CD44std cells demonstrated significant migration and invasion capacities. Furthermore, during the TGF-β-induced EMT process, there was an interchange of colony and sphere formation traits between CD44std and CD44v9 cells, enhancing their migratory, invasive, and adhesive functions. Proteomic analysis and validation of MAPK signaling revealed its activation in both CD44std and CD44v9 cells following TGF-β treatment. These findings demonstrate that CD44std and CD44v9 modify their CSC traits in response to TGF-β, through various signaling pathways, including MAPK, contributing to the development of HCC.

Type of Event: Evaluation Examination
Speaker: M.Sc. Fátima Elizabeth Murillo González
Day: 2023-08-10, at 10:00:00 hrs.
Place: Cell Biology´s seminar classroom
Title: Molecular characterization of the AHR-mediated human parkin gene (PRKN) expression in neuroblastoma cells
Abstract:

Parkin is an E3 ligase enzyme that regulate protein degradation and mitophagy in dopaminergic neurons. Deficiencies in Parkin expression or function result in cellular stress, degeneration, and eventual death of dopaminergic neurons, contributing to the development of Parkinson´s disease. Conversely, overexpression of Parkin enhances neuronal survival. Previous studies have shown that the Aryl Hydrocarbon Receptor (AHR) mediates Parkin upregulation in mice; however, the underlying mechanism in human cells remains to be elucidated. In this study, we described the molecular mechanism by which AHR mediates the upregulation of Parkin in human SH-SY5Y neuroblastoma cells, using two AHR agonists: 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the tryptophan catabolite kynurenine. Our study demonstrate that AHR regulates human Parkin gene (PRKN) through two distinct pathways depending on the ligand. The TCDD-mediated upregulation of Parkin involves the promotion of endoplasmic reticulum stress and the AHR-mediated induction of ATF4, which is a key activating transcription factor of PRKN. On the other hand, kynurenine, a nontoxic AHR agonist, directly induces Parkin transcription by promoting AHR binding to the PRKN gene promoter without activating ER stress pathways. Our findings demonstrate that AHR activation represents a potential pharmacological pathway to induce human Parkin. However, attention must be exercised regarding the nature of the AHR ligand to mitigate potential neurotoxic side effects.

Type of Event: Evaluation Examination
Speaker: M.Sc. Tania Reyes Miguel
Day: 2023-09-14, at 12:00:00 hrs.
Place: Cell Biology´s seminar classroom
Title: CDC42 drives RHOA activity and actin polymerization during capacitation
Abstract:

Mammalian sperm acquire their fertilizing capacity because of a process called capacitation. Actin polymerization is important for capacitation; Inhibition of actin polymerization prevents adhesion and fusion of the sperm with the egg. The main function of the Rho proteins, as CDC42 and RhoA, is in the actin polymerization. Although these two proteins are present in mammalian spermatozoa, little is known about their role in capacitation, acrosomal reaction and in the pathway in which they polymerize actin. The purpose of this study was to determine the participation of CDC42 and RhoA in capacitation and acrosomal capacitation and its relationship with actin polymerization using guinea pig spermatozoa. Our results show that inhibition of CDC42 and RhoA alter the kinetics of polymerization, capacitation and acrosomal reaction in different ways. They also show that the initiation of actin polymerization and the activation of RhoA depend on the activation of CDC42 and that RhoA initiates this activity and affects actin polymerization when CDC42 reaches its maximum activity. Since the inhibition of ROCK1, can´t prevent the acrosomal reaction, the participation of RhoA in the capacitation and the acrosomal reaction is independent of Rho Kinase 1 (ROCK1). In general, our results indicate that CDC42 and RhoA have different roles in the capacitation and acrosomal reaction processes. Additionally, CDC42 plays a relevant role in the regulation of these processes.

Exams

Type of Event: M.Sc. EXAMINATION
Speaker: Cristhina Estefania Jaramillo Ordoñez
Day: 2023-07-13, at 12:00:00 hrs.
Place: Closed door Student with Teachers College & committee in the Cell Biology´s seminar classroom. via TEAMS to the rest of the department
Title: Standardization of the expression of latrofilin-3 in neuroblastoma cells to analyze its participation in neurodegenerative processes
Abstract:

Latrophilin 3 (Lphn-3) is a G protein-coupled adhesion receptor, which is expressed mainly in the brain and participates in various processes such as synapse formation, intercellular adhesion, and the activation of different signaling pathways that promote the remodeling of the actin cytoskeleton. However, its abnormal expression and specific structure have been associated with establishing various neurological processes that result in neurodevelopment. Various studies have used cell models to learn more about this receptor´s normal and pathological properties, using non-neuronal cells for the exogenous expression of this molecule and its mutated variants. However, in vitro, cultured neuronal cell models have yet to be used for the same purpose. This initial study pretends to standardize in vitro the exogenous expression of Lphn-3 in cultured neuroblastoma cells to evaluate in the future the pathological or neuroprotective role of this molecule in some other neurological processes, such as Alzheimer´s disease.

Type of Event: Final Doctoral Examination
Speaker: M.Sc. Mariana del Carmen Orozco Uribe
Day: 2023-07-14, at 12:00:00 hrs.
Place: closed door Department of Cell Biology´s conference classroom, TEAMS to the entire department
Title: Identification and characterization of plasma cells in mice lymphoid tissue during early postnatal development
Abstract:

Plasma cells (PCs) are terminally differentiated cells responsibles of antibody production and are the result of B cell activation responding to T-independent or T-dependent antigens. PCs are very scarce in circulation of non-immunized individuals. Is generally believed that neonates are uncapable to mount efficient responses to antigens during their earliest stages of development. We decided to seek for the presence of PCs in lymphoid organs of non-immunized mice using flow cytometry, immunofluorescence and ELISPOT. We were able to identify PCs from day 1 after birth using the combination of CD138 and CD98, these PCs exhibit an heterogeneous phenotype and secrete Igs, mainly IgM isotype. Our results suggest that neonates are capable of generating their own antibody-secreting cells in response to the antigens they encounter in their first weeks of life.

Type of Event: M.Sc. EXAMINATION
Speaker: Enrique Nicolai Darquea Bustillos
Day: 2023-07-25, at 10:00:00 hrs.
Place: Cell Biology´s seminar classroom
Title: Standardization in obtaining ovine cells for the evaluation of the effect of bovine lactoferrin on Mannheimia haemolytica A2 adhesion
Abstract:

Mannheimia haemolytica is a Gram-negative coccobacillus belonging to the Pasteurellaceae family. This bacterial species normally inhabits the nasal cavity and tonsils of healthy ruminants. However, when the animal is immunosuppressed, M. haemolytica becomes an opportunistic pathogen that migrates to the lungs, where it invades the alveolar epithelium, causing a respiratory pathology known as mannheimiosis. Serotype A1 is associated with mannheimiosis in cattle, while serotype A2 is the cause of ovine mannheimiosis. The bacterium possesses a potent leukotoxin, as well as several adhesins that mediate the initial contact of the microorganism with the cells it infects. Currently, there is no effective pharmacological treatment or completely efficient vaccines available to treat mannheimiosis. As a result, the use of alternative treatments has emerged, including the use of lactoferrin. This glycoprotein from the innate immune system of mammals is present in significant concentrations in colostrum and milk. Among other things, it has an antibacterial effect due to its ability to bind iron or directly interact with components of the outer membrane of Gram-negative bacteria. In this regard, the present research aimed to standardize protocols for obtaining ovine cells to analyze the effect of bovine apo-Lactoferrin (apo-BLf), administered at different concentrations, on the adhesion of M. haemolytica A2 to these cells. Specifically, the study focused on obtaining ovine buccal epithelial cells, as well as ovine peripheral blood monocytes and macrophages. Once the cell populations were purified, adhesion assays of the bacteria to these cells were performed using different concentrations of apo-BLf. Optical, confocal, and epifluorescence microscopy were used for the analysis and quantification of the number of bacteria adhered to each cell type. Thus, it was determined that the parameters for obtaining ovine buccal epithelial cells need to be modified in order to obtain a significant quantity of these cells for conducting an adhesion assay. On the other hand, doses of 20 µM, 30 µM, and 50 µM of apo-BLf decreased the adhesion of M. haemolytica A2 to ovine peripheral blood monocytes by 58%, 69%, and 68%, respectively. Similarly, doses of 20 µM, 30 µM, and 50 µM of apo-BLf decreased the adhesion of M. haemolytica A2 to ovine peripheral blood macrophages by 34%, 67%, and 67%, respectively. These results suggest a need for changing the parameters for obtaining and handling ovine buccal epithelial cells in order to conduct bacterial adhesion assays on them. Finally, a possible use of apo-LfB to prevent the adhesion of M. haemolytica A2 to ovine peripheral blood monocytes and macrophages is suggested.

Type of Event: M.Sc. EXAMINATION
Speaker: Montserrat Gutiérrez Soto
Day: 2023-07-26, at 11:00:00 hrs.
Place: Cell Biology´s seminar classroom
Title: Identification of the Pic receptor for enteroaggregative Escherichia coli in goblet cells by in silico and in vitro assays
Abstract:

Enteroagradative Escherichia coli (EAEC) is associated with acute diarrhea in children and adults. Among its EAEC virulence factors is the Pic protein, important in the colonization of the intestinal epithelium of the host. Recently, it was reported that Pic has dual activity as a mucin secretagogue in goblet cells, independent of its serine protease motif, and as a mucinase, which is dependent on this motif. In that work was also described that the molecular mechanism for the rapid secretion of mucins is related to the PLC/DAG-IP3/Calcium pathway. However, the goblet cell receptor that triggers this entire signaling pathway is unknown until now. Therefore, we consider to determine which is the receptor that triggers this signaling pathway, as well as the motif sequence in Pic that recognizes this receptor. To determinate this, we first performed an in silico analysis in which we three-dimensionally modeled the passenger domain (DP) of Pic, to subsequently make molecular dockings with the candidate receptors and DP Pic. We found that the probable molecular interactions interacted were: with A1R and PAR2 at the d1 subdomain, while ALX/FPR2, P2Y2R and EGFR interacted with the d2 subdomain. Within all the molecular dockings, we identified that the one with the highest affinity of interaction was the PAR2 receptor with the d1 subdomain presenting an affinity energy of ꟷ8.8 kcal/mol and its Kd of 3.6 ´ 10-7. With these results, we proceeded to construct a Pic mutant, deleting the d1 subdomain of PD Pic (PicΔd1) by inverse PCR. This mutant has 3,310 base pairs in length and the secreted PicΔd1 protein has a molecular weight of 82.6 kDa. The pTrcHis2B::picΔd1 construct and the in silico assays performed in this project will serve to identify the receptor that binds to DP Pic to trigger the rapid mucin secretion signaling pathway.

Type of Event: M.Sc. EXAMINATION
Speaker: Mónica Vizcarra Soto
Day: 2023-07-28, at 10:00:00 hrs.
Place: Cell Biology´s seminar classroom
Title: Participation of cyclooxygenase-1 in the secretion/cargo of extracellular vesicles in migration and metastasis processes in an in vitro and in vivo model of breast cancer
Abstract:

Breast cancer is the neoplasia with the highest incidence and mortality in women, nationally and worldwide. Most cancer deaths are associated with a metastatic process, which can be promoted by extracellular vesicles (EVs) derived from cancer cells. Previous studies have shown that linoleic acid (LA), the main omega-6 fatty acid in the Western diet, induces migration and invasion in MDA-MB-231 breast cancer cells, in addition to the release of EVs that promote these processes in an autocrine manner, as well as epithelial-mesenchymal transition in MCF10A cells. In the present work, we demonstrate that LA-induced migration and invasion is dependent on COX-1 activity in MDA-MB-231 and 4T1 cells. It was also shown that LA induces an increase in VEs secretion, which is independent of COX-1 activity in MDA-MB-231 cells. However, EVs induced by LA are captured in a higher proportion and induce migration, invasion, and greater metastatic capacity to lung and liver in 4T1 cells; by inhibiting COX-1 in the cells of origin, the derived EVs do not induce these effects. Therefore, the results of this work suggest that LA induces the inclusion of molecules in EVs that cause a greater metastatic capacity in breast cancer cells, and this charge is dependent on COX-1 activity.

Type of Event: M.Sc. EXAMINATION
Speaker: Jesús Yaniel Ayala Camejo
Day: 2023-07-28, at 12:00:00 hrs.
Place: Cell Biology´s seminar classroom
Title: Obtaining subcellular fractions from Selinexor-treated healthy and progeroid fibroblasts for proteomic analysis
Abstract:

Hutchinson-Gilford progeroid syndrome (HGPS) is characterized by accelerated and premature aging that mimics the characteristics of biological aging. The most common genetic origin of this disease lies in the mutation (C1824→T) in the LMNA gene, which codes for lamin A/C. This change activates a cryptic splicing site that causes the deletion of 50 amino acids in the mutated protein, also known as progerin. Progerin causes multiple cellular alterations that lead to cellular senescence and general aging. Recently, our work group demonstrated that in individuals with HGPS, the export of nuclear proteins is increased by the overexpression of the exportin XPO1 and that treatment of progeroid fibroblasts with Selinexor, a specific XPO1 inhibitor, normalizes nuclear export and decreases several brands of cellular senescence. However, it is still unknown which proteins are involved in the recovery of the normal phenotype. To answer this question, we planned to study the sub-proteomes of the nuclear and cytoplasmic fractions of progeroid fibroblasts when treated with and in the absence of Selinexor. In this work we implemented a cell fractionation strategy that allowed us to obtain nuclear and cytoplasmic extracts with the purity necessary for proteomic studies. The efficacy of Selinexor to retain proteins with a nuclear export signal in the nucleus was also confirmed, and p53 was reinforced as an excellent candidate to verify the effect of selective inhibitors of nuclear export on nuclear-cytoplasmic traffic. Once concluded, this study will contribute to elucidate the molecular mechanisms that are affected in individuals with HGPS, which could be extrapolated to what happens during physiological aging.

Type of Event: M.Sc. EXAMINATION
Speaker: Q.B.T. Susana María Ayala Cháidez
Day: 2023-09-13, at 10:00:00 hrs.
Place: Cell Biology´s seminar classroom
Title: Regulation of neuronal L-type calcium channels (CaV1.3) by α-synuclein
Abstract:

Calcium ions contribute to determining the electrical properties of excitable cells and function as a second messenger in different physiological events. For its entry into cells, calcium requires permeability pathways in the plasma membrane, among which voltage-gated calcium channels (CaV) are prominent. These channels are classified into two families, low voltage-activated (LVA) channels, conformed by an ion-conducting subunit CaVα1, and high voltage-activated (HVA) channels, comprising the CaVα1 subunit and auxiliary subunits called CaVβ, CaVα2δ, and CaVγ. Depending on the type of CaVα1 subunit that the channel contains, Cav channels are classified into three subfamilies (CaV1-CaV3). The CaV1 channels (type L) include the CaV1.3 channels that are the central object of study in this thesis work. In pathological states, CaV1.3 channels participate in neurodegenerative diseases such as Parkinson´s disease (PD), characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta and which triggers the classic motor symptoms of the disease. In addition, the pathophysiology of PD has the participation of the cytosolic protein α-synuclein (α-syn), a regulator of synaptic homeostasis, which is abundant in neurons and is not natively structured. Interestingly, in PD, elevated intracellular calcium induces α-syn oligomerization and aggregation, and it has been speculated that α-syn could, in turn, regulate calcium channel activity. This thesis shows evidence of a possible molecular interaction between CaV1.3 channels and α-syn, using the PLA technique in the HEK-293 cell line transiently transfected with the channel complex and the α-syn protein. Furthermore, the possible functional relevance of this novel molecular interaction was studied by electrophysiology in HEK-293 cells heterologously expressing CaV1.3 channels in the absence and presence of α-syn. Interestingly, the data show a differential regulation of α-syn on CaV1.3 channels that seems to depend on the type of CaVβ subunit present in the channel complex. Taken together, the results show a probable relationship, hitherto unknown, relevant to the physiology of neurons, and given that both molecules have been implicated in the pathophysiology of PD, it may lay the foundations for an important field of study.