Membrane Receptors Research Articles

Inhibitor Development for α-Synuclein Fibril's Disordered Region to Alleviate Parkinson's Disease Pathology.

The amyloid fibrils of α-synuclein (α-syn) are crucial in the pathology of Parkinson's disease (PD), with the intrinsically disordered region (IDR) of its C-terminal playing a key role in interacting with receptors like LAG3 and RAGE, facilitating pathological neuronal spread and inflammation. In this study, we identified Givinostat (GS) as an effective inhibitor that disrupts the interaction of α-syn fibrils with receptors such as LAG3 and RAGE through high-throughput screening. By exploring the structure-activity relationship and optimizing GS, we developed several lead compounds, including GSD-16-24. Utilizing solution-state and solid-state NMR, along with cryo-EM techniques, we demonstrated that GSD-16-24 binds directly to the C-terminal IDR of α-syn monomer and fibril, preventing the fibril from binding to the receptors. Furthermore, GSD-16-24 significantly inhibits the association of α-syn fibrils with membrane receptors, thereby reducing neuronal propagation and pro-inflammatory effects of α-syn fibrils. Our findings introduce a novel approach to mitigate the pathological effects of α-syn fibrils by targeting their IDR with small molecules, offering potential leads for the development of clinical drugs to treat PD.

Deciphering the Interdomain Coupling in a Gram-Negative Bacterial Membrane Insertase.

YidC is a membrane protein that plays an important role in inserting newly generated proteins into lipid membranes. The Sec-dependent complex is responsible for inserting proteins into the lipid bilayer in bacteria. YidC facilitates the insertion and folding of membrane proteins, both in conjunction with the Sec complex and independently. Additionally, YidC acts as a chaperone during the folding of proteins. Multiple investigations have conclusively shown that Gram-positive bacterial YidC has Sec-independent insertion mechanisms. Through the use of microsecond-level all-atom molecular dynamics (MD) simulations, we have carried out an in-depth investigation of the YidC protein originating from Gram-negative bacteria. This research sheds light on the significance of multiple domains of the YidC structure at a detailed molecular level by utilizing equilibrium MD simulations. Specifically, multiple models of YidC embedded in the lipid bilayer were constructed to characterize the critical role of the C2 loop and the periplasmic domain (PD) present in Gram-negative YidC, which is absent in its Gram-positive counterpart. Based on our results, the C2 loop plays a role in the overall stabilization of the protein, most notably in the transmembrane (TM) region, and it also has an allosteric influence on the PD region. We have found critical inter- and intradomain interactions that contribute to the stability of the protein and its function. Finally, our study provides a hypothetical Sec-independent insertion mechanism for Gram-negative bacterial YidC.

Anionic cardiolipin stabilizes the transmembrane region of hyaluronan synthase and promotes catalysis-relevant dynamics

Hyaluronic acid (HA) is a glycosaminoglycan essential for cellular processes and finding increasingly applications in medicine, pharmaceuticals, and cosmetics. While membrane-integrated Class I hyaluronan synthase (HAS) catalyzes HA synthesis in most organisms, the molecular mechanisms by which HAS-lipid interactions impact HAS catalysis remain unclear. This study employed coarse-grained molecular dynamics simulation combined with dimensionality reduction to uncover the interplay between lipids and Streptococcus equisimilis HAS (SeHAS). A minimum of 67 % cardiolipin is necessary for HA synthesis, as determined through simulations using gradient-composed membranes. The anionic cardiolipin stabilizes the cationic transmembrane regions of SeHAS and thereby maintains its conformation. Moreover, the highly dynamic cardiolipin is required to modulate the catalysis-relevant motions in HAS and thus facilitate HA synthesis. These findings provide molecular insights essential not only for understanding the physiological functions of HAS, but also for the development of cell factories and enzyme catalysts for HA production.

Protein-Sequence-Based Search of Nonreceptor ITAM-Like Regions to Identify Cytosolic Syk-Recruiting Proteins.

The recruitment of the protein spleen tyrosine kinase (Syk) to membrane-bound immune receptors is an essential step in initiating an immune response mediated through the activated receptors. Syk recognizes intracellular phosphorylated regions of membrane receptors known as immunoreceptor tyrosine-based activation motifs (ITAMs) defined by a sequence with two tyrosine (Y) amino acids separated by a certain spacing of six to eight residues: YXX(I/L)X6-8YXX(I/L). Syk with doubly phosphorylated ITAM is high-affinity and negatively regulated when Syk itself becomes phosphorylated. While the role of Syk in immune signaling is well characterized, recent information affords new functionality to Syk related to cytoplasmic processes, including the clearance of stress granules and P-bodies, both formed by liquid-liquid phase separation. Little to nothing is known about the molecular interactions involving Syk in these cytoplasmic processes. Given the essential role of receptor ITAMs in recruiting and localizing Syk for immune signaling, we explore here the possibility of a similar localization mechanism occurring for cytoplasmic processes by searching sequences of proteins related to Syk cytoplasmic function for regions that resemble receptor ITAMs. Protein sequence databases were generated from a Syk-dependent phosphoproteome and from genes related to P-bodies. A search of these databases for ITAM-like sequences yielded 102 unique hits, and 33 of these were synthesized and tested experimentally for binding to Syk tandem SH2 domains. The equilibrium dissociation constants were 0.1-50 μM for 28 peptides, and binding was negatively regulated by phosphorylation for many peptides. These results identify cytoplasmic proteins with potential for regulating the localization of Syk in a phosphorylation-dependent manner to nonmembrane cellular regions.

Identification of a Mnlrig-1 involved in testis reproductive immunity in the oriental river prawn Macrobrachium nipponense

The testis evolves a highly organized testicular microenvironment to support spermatogenesis. However, the knowledge about it is limited in crustacean. In this study, we identified a member of immunoglobulin superfamily (IgSF) from Macrobrachium nipponense testis and explored its roles as a potential pattern recognition receptor (PRR) involved in reproductive immunity. Based on the domains it contains and homology analysis result, we designate it as leucine-rich repeats and immunoglobulin-like domains protein-1 (MnLrig-1). The Mnlrig-1 comprises a 3288 bp open reading frame (ORF) encoding a 1095 amino acid protein. MnLrig-1 is consisted of one signaling peptide; one LRR_NT domain; eight LRR domains; five LRR_TYP domains; one LRR_CT domain; three IGc2 regions; one transmembrane region, and C-terminal cytoplasmic tail, sharing similar domains with orthologs in other crustacean species. MnLrig-1 is widely expressed in various tissues of M. nipponense. Mnlrig-1 is significantly induced by LPS, PGN, Aeromonas hydrophila, and Vibrio alginolyticus challenge in the testis at 3 h and maintained a high level from 3 h to 24 h. Additionally, two recombinant immunoglobulin domains of MnLrig-1 are obtained, while only one domain shows direct binding affinity towards LPS, PGN, Escherichia coli, A. hydrophila, Staphylococcus aureus, and Bacillus subtilis in vitro. Moreover, silencing Mnlrig-1 results in a significant upregulation of three anti-lipopolysaccharide factors (ALFs) in the testis. These results reveal the potential role of MnLrig-1 as a PRR involved in the testis reproductive immunity in M. nipponense. The insights gained from this study will expand our understanding of immune system in crustacean and may have implications for aquaculture and disease management in crustaceans.

Cloning and Expression Analysis of TGF-β Type I Receptor Gene in Hyriopsis cumingii.

The TGF-β signaling pathway plays an important role in wound healing and immune response. In this study, a TGF-β type I receptor (TGF-βRI) homolog was cloned and characterized from freshwater mussel Hyriopsis cumingii. The full-length cDNA of the TGF-β RI gene was 2017 bp, with a 1554 bp open reading frame (ORF), and encoded 517 amino acids. The predictive analysis further identified distinct regions within the TGF-βRI protein: a signal peptide, a membrane outer region, a transmembrane region, and an intracellular region. Real-time quantitative PCR results showed that the TGF-β RI gene was expressed in all tissues of healthy mussels. The transcripts of TGF-β RI in hemocytes and hepatopancreas were significantly up-regulated at different periods after stimulation with Aeromonas hydrophila and peptidoglycan (PGN) (P < 0.05). The mRNA expression of TGF-β RI progressively increased from day 1 to day 10 after trauma (P < 0.05), and it returned to the initial level by day 15. The expression levels of TGF-β , Smad5, MMP1/19, and TIMP1/2, but not Smad3/4, were significantly up-regulated at different time points after trauma. However, the expression levels of TGF-β , MMP1/19, and TIMP2 were decreased after treatment with the inhibitor SB431542. Furthermore, the recombinant TGF-βRI proteins were expressed in vitro and existed in the form of inclusion bodies. Western blotting results showed that TGF-βRI proteins were expressed constitutively in various tissues of mussels, and their expression was up-regulated after trauma, which was consistent with the mRNA expression trend. These results indicate that TGF-β RI is involved in the process of wound repair and immune response.

Characterization and Expression Analysis of the C-Type Lectin Ladderlectin in Litopenaeus vannamei Post-WSSV Infection.

C-type lectins are known for agglutination activity and play crucial roles in regulating the prophenoloxidase (proPO) activation system, enhancing phagocytosis and encapsulation, synthesizing antimicrobial peptides, and mediating antiviral immune responses. This work cloned a C-type lectin, ladderlectin (LvLL), from Litopenaeus vannamei. LvLL comprised a 531 bp open reading frame (ORF) that encoded 176 amino acids. The predicted LvLL protein included a signal peptide and a CLECT domain. LvLL was predicted to feature a transmembrane region, suggesting it may be a transmembrane protein. LvLL was predominantly expressed in the shrimp's hepatopancreas. After WSSV infection, LvLL expression in the hepatopancreas increased significantly by 11.35-fold after 228 h, indicating a general upregulation. Knockdown of LvLL resulted in a significant decrease in WSSV viral load and a notable increase in shrimp survival rates. Additionally, knockdown of LvLL led to a significant downregulation of apoptosis-related genes Bcl-2 and caspase 8 and a significant upregulation of p53 and proPO in WSSV-infected shrimp. This study showed that LvLL played a vital role in the interaction between L. vannamei and WSSV.

Abstract A050: The impact of air pollution on aggressive breast cancer prognoses in women of African descent

Abstract Significance. Breast cancer (BC) is the most diagnosed cancer among women in the US. Though highly heterogeneous, different subtypes can be characterized by the expression of membrane receptors on the cell surface: ER+, HER2+, PR+, or basal-like which does not express any of the three receptors. Basal-like triple-negative breast cancer (TNBC) is a highly aggressive subtype of BC that represents about 15% of overall BC cases. Black women disproportionately experience higher rates of early-onset TNBC phenotypes and worse prognoses when compared to White women. Though genetics is a key factor in oncogenesis and cancer progression, it is now widely recognized that differences in cancer outcomes are influenced, also, by various environmental, social, and lifestyle factors known collectively as the social determinants of health (SDOH). For example, air pollution has consistently been shown to be associated with an increased risk of breast cancer, however, little is known about how air pollution alters biological and molecular mechanisms impacting breast cancer progression. Elucidating these influential factors is critical to understanding and addressing disparate outcomes. We are interested in understanding how air pollution impacts immune-oncology related proteins in breast cancer, specifically for Black and White women living in Baltimore City, Maryland. Methods. In a cohort of 217 women (142 Black, 75 White), we performed statistical analyses to determine the correlation between particulate matter 2.5 (PM2.5) with breast cancer subtype and oncogenic molecular drivers within the tumor and its microenvironment. PM2.5 concentration for Census year 2000 was measured using the EPA Downscale Model. Concentrations at the census-tract level were then linked to each participant's geocoded residential address at study baseline. Results. [BJ1] Our data reveal that a higher exposure to PM2.5 is correlated with breast cancer subtypes incidences[BJ2] (p- value[BJ3] =0.051), specifically for hormone receptor positive (ER+ and/or PR+) and TNBC subtypes (p-value=0.035). Elevated air pollution is also associated with estrogen-receptor status overall (p-value=0.002) and in Black (p-value=0.043) and White (p-value=0.008) women in the stratified analysis. Serum protein measurements in this cohort also revealed significant relationships between elevated air pollution and immune-oncology related proteins, including PD-L1, CAIX, CXCL9, and MCP-2.Discussion. Our preliminary evidence reveals an association between air pollution, breast cancer subtypes, and immune-oncology related proteins, with some of these relationships affecting Black and White populations differently. We will continue to interrogate these differences and begin to reveal the underlying mechanisms exacerbating breast cancer disparities. Citation Format: Kayla S. Ingram, Brittany Jenkins-Lord. The impact of air pollution on aggressive breast cancer prognoses in women of African descent [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr A050.

Effects of Therapeutically Approved Individual Bile Acids on The Development of Metabolic Dysfunction-Associated Steatohepatitis a Low Bile Acid Mouse Model

Abstract Bile acid (BA) signaling dysregulation is an important etiology for the development of Metabolic Dysfunction-associated Steatotic Liver Disease (MASLD). As diverse signaling molecules synthesized in the liver by pathways initiated with CYP7A1 and CYP27A1, BAs are endogenous modulators of farnesoid x receptor (FXR). FXR activation is crucial in maintaining BA homeostasis, regulating lipid metabolism, and suppressing inflammation. Additionally, BAs interact with membrane receptors and gut microbiota to regulate energy expenditure and intestinal health. Complex modulation of BAs in vivo and the lack of suitable animal models impede our understanding of the functions of individual BAs, especially during MASLD development. Previously, we determined that acute feeding of individual BAs differentially affects lipid, inflammation, and oxidative stress pathways in a low-BA mouse model, Cyp7a1/Cyp27a1 double knockout (DKO) mice. Currently, we investigated to what degree that cholic acid (CA), deoxycholic acid (DCA) or ursodeoxycholic acid (UDCA) at physiological concentrations impact MASLD development in DKO mice. The results showed that these three BAs varied in ability to activate hepatic and intestinal FXR, disrupt lipid homeostasis, and modulate inflammation and fibrosis. Additionally, UDCA activated intestinal FXR in these low-BA mice. Significant alterations in lipid uptake and metabolism in DKO mice following CA and DCA feeding indicate differences in cholesterol and lipid handling across genotypes. Overall, the DKO were less susceptible to weight gain, but more susceptible to MASH diet induced inflammation and fibrosis on CA and DCA supplement, while WT mice were more vulnerable to CA-induced fibrosis on control diet.

Multitarget-Directed Ligands Hitting Serotonin Receptors: A Medicinal Chemistry Survey.

Serotonin (5-hydroxytryptamine, 5-HT) is a ubiquitous neurotransmitter in the human body. In the central nervous system, 5-HT affects sleep, pain, mood, appetite, and attention, while in the peripheral nervous system, 5-HT modulates peristalsis, mucus production, and blood vessel dilation. Fourteen membrane receptors mediate 5-HT activity. In agreement with the crucial roles played by 5-HT, many drugs target 5-HT receptors (5-HTRs). Therefore, it is unsurprising that many efforts have been devoted to discovering multitarget-directed ligands (MTDLs) capable of engaging one or more 5-HTRs plus another target phenotypically linked to a particular disease. In this review, we will describe medicinal chemistry efforts in designing MTDLs encompassing activity for one or more 5-HTRs, starting with atypical antipsychotics and moving to dual 5-HT1AR/serotonin transporter ligands, 5-HT6R antagonists/acetyl cholinesterases inhibitors, and 5-HT4R agonists/acetyl cholinesterases inhibitors. We will also provide an outlook on the most recent efforts made in the field.

How Protein Depletion Balances Thrombosis and Bleeding Risk in the Context of Platelet's Activatory and Negative Signaling.

Platelets are small cell fragments that play a crucial role in hemostasis, requiring fast response times and fine signaling pathway regulation. For this regulation, platelets require a balance between two pathway types: the activatory and negative signaling pathways. Activatory signaling mediators are positive responses that enhance stimuli initiated by a receptor in the platelet membrane. Negative signaling regulates and controls the responses downstream of the same receptors to roll back or even avoid spontaneous thrombotic events. Several blood-related pathologies can be observed when these processes are unregulated, such as massive bleeding in activatory signaling inhibition or thrombotic events for negative signaling inhibition. The study of each protein and metabolite in isolation does not help to understand the role of the protein or how it can be contrasted; however, understanding the balance between active and negative signaling could help develop effective therapies to prevent thrombotic events and bleeding disorders.

Distinct negative-sense RNA viruses induce a common set of transcripts encoding proteins forming an extensive network.

The large group of negative-strand RNA viruses (NSVs) comprises many important pathogens. To identify conserved patterns in host responses, we systematically compared changes in the cellular RNA levels after infection of human hepatoma cells with nine different NSVs of different virulence degrees. RNA sequencing experiments indicated that the amount of viral RNA in host cells correlates with the number of differentially expressed host cell transcripts. Time-resolved differential gene expression analysis revealed a common set of 178 RNAs that are regulated by all NSVs analyzed. A newly developed open access web application allows downloads and visualizations of all gene expression comparisons for individual viruses over time or between several viruses. Most of the genes included in the core set of commonly differentially expressed genes (DEGs) encode proteins that serve as membrane receptors, signaling proteins and regulators of transcription. They mainly function in signal transduction and control immunity, metabolism, and cell survival. One hundred sixty-five of the DEGs encode host proteins from which 47 have already been linked to the regulation of viral infections in previous studies and 89 proteins form a complex interaction network that may function as a core hub to control NSV infections.IMPORTANCEThe infection of cells with negative-strand RNA viruses leads to the differential expression of many host cell RNAs. The differential spectrum of virus-regulated RNAs reflects a large variety of events including anti-viral responses, cell remodeling, and cell damage. Here, these virus-specific differences and similarities in the regulated RNAs were measured in a highly standardized model. A newly developed app allows interested scientists a wide range of comparisons and visualizations.

Relaxin Modulates the Genomic Actions and Biological Effects of Estrogen in the Myometrium.

Estradiol (E2) and relaxin (Rln) are steroid and polypeptide hormones, respectively, with important roles in the female reproductive tract, including myometrium. Some actions of Rln, which are mediated by its membrane receptor RXFP1, require or are augmented by E2 signaling through its cognate nuclear steroid receptor, estrogen receptor alpha (ERα). In contrast, other actions of Rln act in opposition to the effects of E2. Here we explored the molecular and genomic mechanisms that underlie the functional interplay between E2 and Rln in the myometrium. We used both ovariectomized female mice and immortalized human myometrial cells expressing wild-type or mutant ERα (hTERT-HM-ERα cells). Our results indicate that Rln modulates the genomic actions and biological effects of estrogen in the myometrium and myometrial cells by reducing phosphorylation of ERα on serine 118 (S118), as well as by reducing the E2-dependent binding of ERα across the genome. These effects were associated with changes in the hormone-regulated transcriptome, including a decrease in the E2-dependent expression of some genes and enhanced expression of others. The inhibitory effects of Rln cotreatment on the E2-dependent phosphorylation of ERα required the nuclear dual-specificity phosphatases DUSP1 and DUSP5. Moreover, the inhibitory effects of Rln were reflected in a concomitant inhibition of the E2-dependent contraction of myometrial cells. Collectively, our results identify a pathway that integrates Rln/RXFP1 and E2/ERα signaling, resulting in a convergence of membrane and nuclear signaling pathways to control genomic and biological outcomes.

Platelets as mediators of neuropsychiatric and neurodegenerative diseases

Numerous studies showing platelets' role in mechanisms beyond hemostasis have sparked interest in investigating all the pathways in which they may be involved. A growing body of evidence indicates that platelets play a key role in immune response. Platelets carry various membrane receptors and release many bioactive molecules that recruit and activate immune cells. Consequently, platelets have a significant immunoregulatory role in infectious, inflammatory, and degenerative diseases. Moreover, immune cells contribute to neuronal development, neural plasticity, and neuroglial activation. The interaction between platelets and immune cells reveals an additional regulatory mechanism of brain function. This review explores the relationship between platelets and the central nervous system (CNS). It highlights the role of platelets in the development of severe neurodegenerative and neuropsychiatric diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), multiple sclerosis (MS) and depression.

Up-regulation of MDSCs accumulation and Th2 biased response to co-stimulation of CsESP from Clonorchis sinensis and HBeAg in vitro

Co-infection with Clonorchis sinensis (C. sinensis) and Hepatitis B virus (HBV) are commonly observed in endemic areas of Clonorchiasis. Chronic infection of C. sinensis or HBV is more likely to happen. However, the immune mechanisms related to the pathogenesis of co-infection remain unknown. In the present study, Myeloid-derived suppressor cells (MDSCs) accumulation, bone marrow derived dendritic cells (BMDCs) reaction and the consequent effectors on Th1/Th2 polarization to co-incubation of excretory-secretory products from C. sinensis (CsESP) and Hepatitis B e antigen (HBeAg) in vitro were investigated for further understanding the immune response during co-infection. The results indicated that compared with CsESP or HBeAg alone, co-stimulation dominantly promoted MDSCs accumulation. Co-stimulation significantly downregulated the expression of CD80 and CD86, and reduced IL-12p70 release while augmented IL-10 levels of BMDCs. Higher transcription levels of mannose receptor (MR) while lower mRNA level of toll like receptor 4 (TLR-4) were detected among membrane receptors of BMDCs with co-treatment. In addition, after CD4 naïve T cells were stimulated by LPS-treated BMDCs with CsESP and HBeAg, the proportion of CD4+IL-4+ T cells and IL-4 increased, while CD4+INF-γ+ T cells percentage and INF-γ down-regulated. In conclusion, CsESP and HBeAg co-incubation more distinctly suppressed maturation of BMDCs resulting in increase of IL-10 and decrease of IL-12 highly possible by up-regulation of MR and down-regulation of TLR-4 of BMDCs, and successively induce Th2 immune skewing. These findings laid the cornerstone to further clarify immune responses during the co-infection contributing to the better precise treatment and progression assessment of co-infection patients.

Synthesis of a 13C/2H Labeled Building Block to Probe the Phosphotyrosine Interactome Using Biomolecular NMR Spectroscopy.

Phosphotyrosine (pTyr) recognition coordinates the assembly of protein complexes, thus controlling key events of cell cycle, cell development and programmed cell death. Although many aspects of membrane receptor function and intracellular signal transduction have been deciphered in the last decades, the details of how phosphorylation alters protein-protein interaction and creates regulating switches of protein activity and localization often remains unclear. We developed a synthetic route to a protected phophotyrosine building block with isolated 13C-1H spins in the aromatic ring. The compound can be used for solid phase peptide synthesis (SPPS) and readily applied to study affinity, dynamics and interactions on an atomic level using NMR spectroscopy. As a first example, we prepared an isotopologue of a pTyr containing 12mer peptide (pY1021) as part of the platelet-derived growth factor to analyze the binding to the phospholipase C-γ (PLCγ-1) SH2 domain.

MASTER-NAADP: a membrane permeable precursor of the Ca2+ mobilizing second messenger NAADP

Upon stimulation of membrane receptors, nicotinic acid adenine dinucleotide phosphate (NAADP) is formed as second messenger within seconds and evokes Ca2+ signaling in many different cell types. Here, to directly stimulate NAADP signaling, MASTER-NAADP, a Membrane permeAble, STabilized, bio-rEversibly pRotected precursor of NAADP is synthesized and release of its active NAADP mimetic, benzoic acid C-nucleoside, 2’-phospho-3’F-adenosine-diphosphate, by esterase digestion is confirmed. In the presence of NAADP receptor HN1L/JPT2 (hematological and neurological expressed 1-like protein, HN1L, also known as Jupiter microtubule-associated homolog 2, JPT2), this active NAADP mimetic releases Ca2+ and increases the open probability of type 1 ryanodine receptor. When added to intact cells, MASTER-NAADP initially evokes single local Ca2+ signals of low amplitude. Subsequently, also global Ca2+ signaling is observed in T cells, natural killer cells, and Neuro2A cells. In contrast, control compound MASTER-NADP does not stimulate Ca2+ signaling. Likewise, in cells devoid of HN1L/JPT2, MASTER-NAADP does not affect Ca2+ signaling, confirming that the product released from MASTER-NAADP is a bona fide NAADP mimetic.

The pro-inflammatory cytokines IL-1β and IL-6 promote upregulation of the ST6GAL1 sialyltransferase in pancreatic cancer cells

The ST6GAL1 sialyltransferase is overexpressed in multiple cancers including pancreatic ductal adenocarcinoma (PDAC). ST6GAL1 adds an α2-6-linked sialic acid to N-glycosylated membrane receptors, which consequently modulates receptor structure and function. While many studies have investigated the effects of ST6GAL1 on cell phenotype, there is a dearth of knowledge regarding mechanisms that regulate ST6GAL1 expression. In the current study, we evaluated the regulation of ST6GAL1 by two pro-inflammatory cytokines, IL-1β and IL-6, that are abundant within the PDAC tumor microenvironment. Cytokine activity was monitored using the Suit-2 PDAC cell line and two Suit-2-derived metastatic subclones, S2-013 and S2-LM7AA. For all three cell models, treatment with IL-1β or IL-6 increased the expression of ST6GAL1 protein and mRNA. Specifically, IL-1β and IL-6 induced expression of the ST6GAL1 YZ mRNA isoform, which is driven by the P3 promoter. The ST6GAL1 H and X isoforms were not detected. Promoter reporter assays confirmed that IL-1β and IL-6 activated transcription from the P3 promoter. We then examined downstream signaling mechanisms. IL-1β is known to signal through the NFκB transcription factor, whereas IL-6 signals through the STAT3 transcription factor. CUT&RUN experiments revealed that IL-1β promoted the binding of NFκB to the ST6GAL1 P3 promoter, and IL-6 induced the binding of STAT3 to the P3 promoter. Finally, we determined that inhibitors of NFκB and STAT3 blocked the upregulation of ST6GAL1 stimulated by IL-1β and IL-6, respectively. Together, these results highlight a novel molecular pathway by which cytokines within the tumor microenvironment stimulate the upregulation of ST6GAL1 in PDAC cells.

Exploring the potential of nanoparticles as a drug delivery system for cancer therapy: A review

In this review, we discuss the use of organic nanoparticles such as liposomes, polymeric nanoparticles, dendrimers, and inorganic nanoparticles such as gold nanoparticles and mesoporous silica nanoparticles in drug delivery in chemotherapy for cancer therapy. Another strategy is the use of nanoparticle vehicles for drug delivery through the natural openings on tumor vessels called fenestrations. Both of these can be functionalized to attach angiotensin to lymphocytes or any certain part of the cancer cell membrane, microenvironment, or cytoplasmic or nuclear receptor sites, and therefore a high concentration of drug delivery to targeted cancer cells is achieved, but with less or no toxicity to normal tissue. The potential advantages evident in this technology are useful approaches to established high-concentration drug treatment of cancer tissues without harming normal cells. Some features of a nanoparticle-based drug delivery system include the durability of the vehicle, biocompatibility, permeation, and ability to target specific types of cells. Organic and inorganic nanoparticles have developed this kind of drug-carrier system. Particulate systems are also still being explored for cancer drug resistance mechanisms, and their function in immunotherapy is expanding.

Optimization of SOX2 Expression for Enhanced Glioblastoma Stem Cell Virotherapy

The Zika virus has been shown to infect glioblastoma stem cells via the membrane receptor αvβ5, which is activated by the stem-specific transcription factor SOX2. Since the expression level of SOX2 is an important predictive marker for successful virotherapy, it is important to understand the fundamental mechanisms of the role of SOX2 in the dynamics of cancer stem cells and Zika viruses. In this paper, we develop a mathematical ODE model to investigate the effects of SOX2 expression levels on Zika virotherapy against glioblastoma stem cells. Our study aimed to identify the conditions under which SOX2 expression level, viral infection, and replication can reduce or eradicate the glioblastoma stem cells. Analytic work on the existence and stability conditions of equilibrium points with respect to the basic reproduction number are provided. Numerical results were in good agreement with analytic solutions. Our results show that critical threshold levels of both SOX2 and viral replication, which change the stability of equilibrium points through population dynamics such as transcritical and Hopf bifurcations, were observed. These critical thresholds provide the optimal conditions for SOX2 expression levels and viral bursting sizes to enhance therapeutic efficacy of Zika virotherapy against glioblastoma stem cells. This study provides critical insights into optimizing Zika virus-based treatment for glioblastoma by highlighting the essential role of SOX2 in viral infection and replication.