Biology subjects

Hussain, A.

Publications and source records attributed to Hussain, A..

At least 37 records · Page 2Linked to original sources

bioRxiv2024

Analysis of differential expression of matrix metalloproteins and defensins in the nasopharyngeal milieu of mild and severe COVID-19 cases

IntroductionA subset of COVID-19 disease patients suffers a severe form of the illness, however, underlying early pathophysiological mechanisms associated with the severe form of COVID-19 disease remain to be fully understood. Several studies showed the association of COVID-19 disease severity with the changes in the expression profile of various matrix metalloproteinases (MMPs) and defensins. However, the link between the changes in the expression of matrix metalloproteinase (MMPs) and defensins (DA) in the nasopharyngeal milieu, during early phases of infection, and disease severity remains poorly understood. Therefore, we performed differential gene expression analysis of matrix metalloproteinases (MMPs) and defensins in the nasopharyngeal swab samples collected from mild and severe COVID-19 cases within three days of infection and examined the association between MMP and DA expression and disease severity. Material and MethodA total of 118 previously collected nasopharyngeal samples from mild and severe COVID-19 patients (as per the WHO criteria) were used in this study. To determine the viral loads and assess the mRNA expression of matrix metalloproteinase (MMPs) and defensins, a real-time qPCR assay was used. To assess statistically significant differences in the mean expression of viral loads and the cytokines in between the severe and mild groups, an unpaired T-test was applied. The Pearson correlation test was used to assess the correlation between cytokine expressions. In addition, a multivariable logistic regression analysis was carried out with all the variables from the data set using severity as the outcome variable. ResultsOur results showed that the expression of DA3 and MMP2 to be considerably lower in the severe group than in the mild group. Furthermore, there was a significant association between MMP1 and DA4 and DA6 (r=0.5, p=0.0001); as well as between MMP7 and DA1 and DA6 (r=0.5, p=0.00). Additionally, the regression analysis shows a significant correlation (p 0.05) between MMP2 and the severity of COVID-19 disease. ConclusionThe early detection of changes in the expression of MMPs and defensins may act as a useful biomarker/predictor for possible severe COVID-19 disease, which may be useful in the clinical management of patients to reduce COVID-19-associated morbidity and mortality.

microbiology↗

bioRxiv2023

2-bromo-2',5'-dihydroxychalcone analogue Inhibits Endothelial Migration by Targeting VEGF-induced ERK 1/2 Phosphorylation

Angiogenesis, the process of new blood vessel formation, is characterized by three essential hallmarks: endothelial proliferation, migration, and differentiation. Each is integral in angiogenesis related diseases, especially cancer. With drug efficacy stagnated due to acquired drug resistance and off target side effects, the need for combinatorial therapy is ever more present. To identify new compounds that could aid current antiangiogenic therapies, we report the preliminary mechanistic evaluation of a 2-bromo-25-dihydroxychalcone analogue and its antimigratory effects on endothelial cells. After the synthesis and validation of the 2-bromo-25-dihydroxychalcone analogue (AH9), its effect was tested in vitro using human umbilical vein endothelial cells (HUVEC). Initial investigations into 2-bromo-25-dihydroxychalcone effect in vitro was conducted with a cell proliferation assay including MTT, afterward endothelial migration was measured with the scratch assay in subsequent functional studies. For mechanistic evaluation, vascular endothelial growth factor (VEGF) induced ERK phosphorylation using western blot was implemented. AH9 inhibited VEGF-induced ERK [1/2] phosphorylation similar to that of known antiangiogenic drug Sorafenib at all three concentrations 100 M (46%, p = 0.003), 30 M (64%, p = 0.0002) and 10 M (91%, p = 0.0001). In a scratch assay model, whilst sorafenib at 3 M was not able to limit migration after 8-hr compared to an untreated control (p = 0.0978), AH9 did (17.41%, p = 0.0079). Furthermore, AH9 was able to inhibit ERK [1/2] phosphorylation in a concentration dependent manner 100 M (46%, p = 0.003), 30 M (64%, p = 0.0002) and 10 M (91%, p = 0.0001) compared to the VEGF control. These preliminary findings support that AH9 could be exerting antimigratory effects through the inhibition of the VEGF induced MAPK/ERK pathway. This forms the foundation for further studies to explore chalcone analogues in hope to aid current antiangiogenic therapeutic strategies as potential angiogenic inhibitors.

pharmacology and toxicology↗

bioRxiv2023

The rural urban divide, insights from immuno-genetic profiles and implications for health

Population disparities in health and disease, has been observed, and amply documented. While often attributable to genetic underpinnings, such disparities, extends beyond population genetic predisposition to include environmental and geographic determinants most pronouncedly the division between rural and urban lifestyles. Under such influences, genes and gene products may become affected by epigenetic factors, microbial modifiers including infections and the body microbiome that ultimately shapes the outcome of complex milieu of protein networks. Retrospective, demographic, genotype, and expression data of two rural populations from eastern Sudan were analysed for genotype, allele frequency distribution, Hardy Weinberg Equilibrium and expression profiles using an array panel of Th1, Th2 and Th3 genes in a subset of rural population sample against matched urban control. Differences between urban and rural samples were observed in the departure from HWE with excess of heterozygosity in the rural sample. In the Th1, Th2 and Th3 array, cytokines were consistently overexpressed in the rural as compared to urban cohort and was replicated in 7 selected genes that are associated with chronic diseases amongst urban dwellers in contrast to rural village inhabitants. IgE levels as feature of parasitic infections is one other difference to include in that dichotomy. Gene expression appears to be more exposing to an overall outcome of genetic variations, including the interaction with environmental influences within and outside the body. Here, it may be gathered from the contrast in the expression patterns between the rural and urban samples. The presence of signals of natural selection in genes that are key to certain biological functions as CD40L and FasL, and the sharp contrast between urban and rural populations in gene variants distribution and expression patterns may provide important clues towards understanding the disparity between human communities in non-communicable diseases of lifestyle as well as some of the emerging infectious diseases.

immunology↗

bioRxiv2023

Comparative Analysis, Diversification and Functional Validation of Plant Nucleotide-Binding Site Domain Genes

Nucleotide-binding site (NBS) domain genes are one of a superfamily of resistance genes involved in plant responses to pathogens. The current study identified presumably identified 12,820 NBS-containing genes across 34 species covering from mosses to monocots and dicots. These identified genes classified into 168 classes with several novel domain architectures patterns encompassing significant diversity among plant species. Several classical (NBS, NBS-LRR, TIR-NBS, TIR-NBS-LRR etc.) and species-specific structural patterns (TIR-NBS-TIR-Cupin_1-Cupin_1, TIR-NBS-Prenyltransf, Sugar_tr-NBS etc.) were discovered. We observed 603 orthogroups (OGs) with some core (most common orthogroups; OG0, OG1, OG2 etc.) and unique (highly specific to species; OG80, OG82 etc) OGs with tandem duplications. The expression profiling presented the putative upregulation of OG2, OG6, and OG15 in different tissues under various biotic and abiotic stresses in susceptible and tolerant plants to CLCuD. The genetic variation between susceptible (Coker 312) and tolerant (Mac7) G. hirsutum accessions identified several unique variants in NBS genes of Mac7 (6,583 varaints) and Coker312 (5,173 variants). The protein-ligand and proteins-protein interaction showed a strong interaction of some putative NBS proteins with ADP/ATP and different core proteins of cotton leaf curl disease virus. The silencing of GaNBS (OG2) in resistant cotton through virus-induced gene silencing (VIGS) demonstrated its putative role in virus tittering. The presented study will be further helpful to understand the plant adaptation mechanism.

plant biology↗

bioRxiv2023

Exoribonuclease RNase R protects Antarctic Pseudomonas syringae Lz4W from DNA damage and oxidative stress

RNase R is a highly processive, 3 -5 exoribonuclease involved in RNA degradation, maturation, and processing in bacteria. In Pseudomonas syringae Lz4W, RNase R interacts with RNase E to form the RNA degradosome complex and is essential for growth at low temperature. RNase R is also implicated in general stress response in many bacteria. We show here that the deletion mutant of rnr gene (encoding RNase R) of P. syringae is highly sensitive to various DNA damaging agents and oxidative stress. RNase R is a multidomain protein comprised of CSD, RNB and S1 domains. We investigated the role of each domain of RNase R and its exoribonuclease activity in nucleic acid damage and oxidative stress response. Our results revealed that the RNB domain alone without its exoribonuclease activity is sufficient to protect against DNA damage and oxidative stress. We also show that the association of RNase R with the degradosome complex is not required for this function. Our study has discovered for the first time a hitherto unknown role of RNase R in protecting P. syringae Lz4W against DNA damage and oxidative stress. ImportanceBacterial exoribonucleases play a crucial role in RNA maturation, degradation, quality control and turnover. In this study, we have uncovered a previously unknown role of 3-5 exoribonuclease RNase R of P. syringae Lz4W in DNA damage and oxidative stress response. Here, we show that neither the exoribonuclease function of RNase R, nor its association with the RNA degradosome complex is essential for this function. Interestingly, in P. syringae Lz4W, hydrolytic RNase R exhibits physiological roles similar to phosphorolytic 3-5 exoribonuclease PNPase of E. coli. Our data suggest that during the course of evolution, mesophilic E. coli and psychrotrophic P. syringae have apparently swapped these exoribonucleases to adapt to their respective environmental growth conditions.

microbiology↗

bioRxiv2023

A novel resistance reversion mechanism in a vancomycin-variable Enterococcus faecium strain

ObjectivesTo investigate an outbreak of Enterococcus faecium in a hospital haematology ward and uncover the mechanism of a vancomycin resistance phenotype-genotype disparity in an isolate from this outbreak. MethodsWhole genome shotgun sequencing was used for the phylogenetic analysis of E. faecium isolates (n = 39) and to identify the carriage of antibiotic resistance genes. A long-read sequencing approach was adopted to identify structural variations in the vancomycin resistance region of a vancomycin-variable E. faecium (VVE) and to uncover the resistance reversion mechanism in this isolate. RT-qPCR and RT-PCR were used to determine differences in the expression of vanRS and vanHAX among strains. ResultsThe E. faecium strains isolated in the hospital haematology ward were extensively drug resistant and highly diverse. The notable expansion of ST262 among patients was the likely driver of a VRE outbreak. A VVE isolate was identified that could rapidly revert to a vancomycin-resistant state in the presence of vancomycin. Disruption of the vanR gene in this isolate by an IS6-family element impaired its response to vancomycin. However, when the isolate was evolved to vancomycin resistance, it could constitutively express the vanHAX genes at levels up to 36,000-fold greater than the parent isolate via co-transcription with a ribosomal RNA operon. ConclusionIn this study, we report a VVE isolate that was isolated during a VRE outbreak. This strain was capable of rapidly reverting to a resistant phenotype through a novel mechanism involving integration of vanHAX downstream of a ribosomal RNA operon. During VRE outbreaks, attention should be paid to contemporaneous vancomycin-susceptible strains as these may carry silent vancomycin resistance genes that can be activated through genomic rearrangements upon exposure to vancomycin.

microbiology↗

bioRxiv2023

Semantic feature production norms for manipulable objects

Feature generation tasks and feature databases are important for understanding how knowledge is organized in semantic memory, as they reflect not only the kinds of information that individuals have about objects but also how objects are conceptually parse. Traditionally, semantic norms focus on a variety of object categories, and, as a result, have a small number of concepts per semantic category. Here, our main goal is to create a more finely-tuned feature database exclusively for one category of objects - manipulable objects. This database contributes to the understanding of within-category, content-specific processing. To achieve this, we asked 130 participants to freely generate features for 80 manipulable objects, and another group of 32 participants to generate action features for the same objects. We then compared our databases with other published semantic norms and found high structural similarity between them. In our databases, we calculated the similarity between visual, functional, encyclopedic, and action feature types. We discovered that objects were grouped in a distinctive and meaningful way according to feature type. Finally, we tested the validity of our databases by asking three groups of participants to perform a feature verification task while manipulating production frequency. Our results demonstrate that participants can recognize and associate the features of our databases with specific manipulable objects. Participants were faster to verify high-frequency features than low-frequency features. Overall, our data provide important insights into how we process manipulable objects and can be used to further inform cognitive and neural theories of object processing and identification.

neuroscience↗

bioRxiv2023

Functional antagonistic interactions and genomic insights into the biosynthetic potential of human gut-derived microbiota

Concerning the biological interactions within the gut microbiome, the specialized small molecules encoded by commensal microbes mediate distinct functional aspects. However, the landscape of antagonistic interactions mediated by specialized strains and their small molecules broadly remains. Here, we sought to evaluate antimicrobial interactions as a defensive contributor to gain new insights into structure-related functions or to bring the therapeutic potential of derived molecules. We elucidated the antagonistic landscape within a collection of 330 human-gut-derived commensal microbial strains cultivated from healthy human subjects. We characterized potential antagonistic strains and found a strain-specific selective inhibition contrary to common antimicrobial drugs that wipe out a broad range of species usually found in environmental microbes. Using functional and genomic approaches for accessing biologically active natural product molecules, we identified significant biosynthetic gene clusters (BGCs) encoding the important compound families in representative gut strains which contribute to antagonistic activities and are important in host defense or maintaining homeostasis in the gut. The subsets of the BGCs were represented in metagenomics sequencing data from healthy individuals. The cell culture secretome of strains revealed potential biomarkers linked to hallmark pathways. Together, these microorganisms encode biosynthetic novelty and represent a source of biologically significant natural products important in developing new treatments for infectious diseases to cut the usage of broad-spectrum antibiotics and represent a way to combat antimicrobial resistance. Consortia of such strains can be utilized as an option for precise editing of the microbiomes or fine-tuning the microbiota-modulating therapies.

microbiology↗

bioRxiv2023

A new competitive strategy to unveil the antibiotic-producing Actinobacteria

The bacterial phylum Actinobacteria encompasses microorganisms with incomparable metabolic versatility and deep resource of medicines. However, the recent decrease in the discovery rate of antibiotics warrants innovative strategies to harness actinobacterial resources for lead discovery. Indeed, microbial culturing efforts measuring the outcomes of specific genera lagged behind the detected microbial potential. Herein, we used a distinct competitive strategy that exploits competitive microbial interactions to accelerate the diversification of strain libraries producing antibiotics. This directed-evolution-based strategy shifted the diversity of Actinobacteria over the experimental time course (0-8 days) and led to the isolation of Actinobacterial strains with distinct antimicrobial spectrum against pathogens. To understand the competitive interactions over experimental time, the metagenomic community sequencing revealed that actinobacterial members from families Nocardiaceae and Cellulomonadaceae with relatively increased abundances towards end, are thus competitively advantageous. Whilst comparing the Actinobacteria retrieved in the competitive strategy to that of the routinely used isolation method, the Actinobacteria genera identified from competitive communities differed relatively in abundances as well as antimicrobial spectrum compared to actinobacterial strains retrieved in classical method. In sum, we present a strategy that influences microbial interactions to accelerate the likelihood of potential actinobacterial strains with antimicrobial potencies.

microbiology↗

bioRxiv2022

BBIBP-CorV (Sinopharm) vaccination- induced immunity is affected by age, gender and prior COVID-19 and activates responses to spike and other antigens

Long-term solutions against SARS-CoV-2 infections require understanding of immune protection induced by different vaccine COVID-19 formulations. We investigated humoral and cellular immunity induced by Sinopharm (BBIBP-CorV) in a region of high SARS-CoV-2 seroprevalence. Levels of IgG antibodies to SARS-CoV-2 spike protein and its receptor-binding domain (RBD) were determined 24-weeks. Cellular immunity was investigated using a commercially available IFN-{gamma} release assay to SARS-CoV-2 spike (Ag1 and 2) and extended genome antigens (Ag3). Increasing IgG seropositivity to Spike protein and RBD was observed post-vaccination. Seropositivity was reduced in those over 50 years and raised in females and those with prior COVID-19. After 20 weeks post-vaccination, only one third of participants had positive T cell responses to SARS-CoV-2 antigens. Prior COVID-19 impacted IFN{gamma} responses, with reactivity enhanced in those infected earlier. The frequency of IFN{gamma} responses was highest to extended genome antigen set. Overall, BBIBP-CorV- induced antibody responses were impacted by age, gender and prior COVID-19. Cellular immunity was present in a limited number of individuals after 20 weeks but was enhanced by prior infection. This suggests the need for booster vaccinations in older individuals. BBIBP-CorV-induced cellular activation is broader than to spike, requiring further study to understand how to monitor vaccine effectiveness.

immunology↗

bioRxiv2022

Risk Assessment of the newly emerged H7N9 avian influenza viruses

Since the first human case in 2013, H7N9 avian influenza viruses (AIVs) have caused more than 1500 human infections with a mortality rate of approximately 40%. Despite large-scale poultry vaccination regimes across China, the H7N9 AIVs continue to persist and evolve rapidly in poultry. Recently, several strains of H7N9 AIVs have been isolated and shown the ability to escape vaccine-induced immunity. To assess the zoonotic risk of the recent H7N9 AIV isolates, we rescued viruses with hemagglutinin (HA) and neuraminidase (NA) from these H7N9 AIVs and six internal segments from PR8 virus (A/Puerto Rico/8/34 [H1N1]) and characterized their receptor binding, pH of fusion, thermal stability, plaque morphology and in ovo virus replication. We also assessed the cross-reactivity of the viruses with human monoclonal antibodies (mAbs) against H7N9 HA and ferret antisera against H7N9 AIV candidate vaccines. The H7N9 AIVs from the early epidemic waves had dual sialic acid receptor binding characteristics, whereas the more recent H7N9 AIVs completely lost or retained only weak human sialic acid receptor binding. Compared with the H7N9 AIVs from early epidemic waves (2013-2016), the recent (2020/21) viruses formed larger plaques and increased replication titres in ovo, demonstrating increased acid stability but reduced thermal stability. Further analysis showed that these recent H7N9 AIVs had poor cross-reactivity with the human mAbs and ferret antisera, highlighting the need to update the vaccine candidates. To conclude, the newly emerged H7N9 AIVs showed characteristics of typical AIVs, posing reduced zoonotic risk but a heightened threat for poultry.

microbiology↗

bioRxiv2022

Temporal Vascular Endothelial Growth Factor Sub-type gene Switching in SARS-CoV Pathogenesis. Interpretation through in vivo Murine C57BL Models

This study examines temporal gene expression (GE) patterns in a murine model of SARS-CoV infection. We focused on a Temporal Gene Set (TGS) comprising pro-inflammatory genes (TNF, NFKB1, VEGF-A) and VEGF-B. A systematic search of the NCBI Geo database for MA15 (SARS-CoV) pulmonary studies using C57BL Wild (WT) mice and filtering according to TGS GE patterns eluded seven datasets for further analysis. Encompassing the GE profiles from these datasets alluded to a rising and falling pattern in TNF and NFKB1 GE. Also, our findings reveal a temporal decrease in VEGF-A GE coinciding with an increase in VEGF-B GE post-immunogenic stimulation. Notably, differential responses were observed with the MA15 dosage and in comparison, to other antigens (dORF6 and NSP16). Further, the human SARS-CoV-2 gene enrichment in this murine study confirms the MA15 murine models relevance for SARS research. Our study also suggests potential interactions between SARS-CoV-2 Spike protein and VEGF-related receptors, hinting at other pathophysiological mechanisms. Our results indicate severe inflammation may lead to a flattened VEGF-B GE response, influencing VEGF-Bs cell survival role. We underline the significance of considering VEGF-A/B interactions, particularly temporal differences, in manipulating angiogenic processes. Future research needs to consider temporal changes in VEGF-A and VEGF-B GE, in terms of time-associated gene-switching, in line with changing host inflammation.

immunology↗

bioRxiv2022

Role of DEAD Box RNA helicases in low temperature adapted growth of Antarctic Pseudomonas syringae Lz4W

Nucleic acid metabolism plays an important role in adaptation of organisms to environment. For adaptation to cold environment, organisms need to overcome the impediments in complex RNA secondary structures that are highly stabilized at low temperature affecting metabolism and growth of the organisms. Employing gene disruption through homologous recombination, we investigated the role of all major DEAD box RNA helicases (rhlE, srmB, csdA, dbpA and rhlB) in cold adapted growth of Pseudomonas syringae. Our findings concluded that srmB and dbpA genes are important for cold adapted growth, whereas csdA is indispensable for growth at low temperature. Helicase genes rhlB and rhlE have no appreciable role in cold adapted growth of Pseudomonas syringae. Functional complementation studies revealed that RNA helicases dont have any redundant functions, as the roles performed by different helicases are individual and specific.

microbiology↗

bioRxiv2022

Vasoactive Endothelial Growth Factor and Heat Shock Protein Gene Expression Response in Kawasaki Disease Associated Coronary Arteritis

Kawasaki Disease (KD) is a childhood vasculitis primarily affecting medium-sized arteries, which can lead to severe complications, particularly with respect to coronary artery disease (CAD). The impact of thermal stress on KD coronary artery pathogenesis, in association with prolonged fever and inflammation, remains unclear. In this study, we hypothesized that altered gene expression (GE) of angiogenesis-inducing Heat Shock Proteins (HSPs) is associated with KD-CAD through pro-inflammation. Transcriptomic analysis was performed using the three largest KD peripheral blood studies in the clinical literature (KD1-KD3), and one study direct from coronary artery tissue (KD4). The analysis revealed a significant increase in TNF and NFKB1 GE, indicating the presence of inflammation based on gene expression profiles. Gene set enrichment analysis (GSEA) of KD1-KD3 datasets identified inflammatory pathways, including TNFA signaling via NFKB, IL6 JAK STAT 3 Signalling, and p53 (Heat Shock Protein 90). The study also focused on specific HSPs known to be associated with angiogenesis, namely HSPB1, HSPA1A, and HSP90AB1. The temporal transcript model (TTM) consistently showed up-regulation of pro-inflammatory genes VEGF-A, TNF, and NFKB1, as well as up-regulation of HSPA1A. GSEA revealed gene ontology pathways associated with VEGF production. These findings suggest that the binding of VEGF-A or VEGF-B to their receptors could potentially impact the coronary artery in KD. Additionally, the up-regulation of the gene HSPAB1 in KD has not been described previously. In contrast, KD4 showed no differential GE for the studied genes potentially related to end-stage KD. This study provides valuable insights into VEGF and HSPs in KD-associated inflammation. Future research should focus on developing a VEGF-HSP CAD model to explore implications for KD biomarking as well as developing precision management strategies.

genomics↗

bioRxiv2022

Biological evaluation of novel side chain containing CQTrICh-analogs as antimalarials and their development as PfCDPK1 kinase inhibitors

To combat the emergence of drug resistance against the existing antimalarials, novel side chain containing 7-chloroquinoline-indole-chalcones tethered with a triazole (CQTrICh-analogs 7 (a-s) and 9) were designed and synthesized by reacting substituted 1-phenyl-3-(1-(prop-2-yn-1- yl)-1H-indol-3-yl) prop-2-en-1-one and 1-(prop-2-yn-1-yl)-1H-indole-3-carbaldehyde with 4- azido-7-chloroquinoline, respectively via a click reaction. The selected CQTrICh-analogs: 7l and 7r inhibited chloroquine-sensitive (3D7) and resistant (RKL-9) strains of Plasmodium falciparum, with IC50 values of 2.4 {micro}M & 1.8 {micro}M (7l), and 3.5 {micro}M & 2.7 {micro}M (7r), respectively, and showed insignificant hemolysis and cytotoxicity in mammalian cells. Intra-erythrocytic progression studies revealed that the active hybrids: 7l and 7r are effective against the mature stages of the parasite. Given the importance of Calcium-Dependent Protein Kinase 1 (PfCDPK1) in the parasite biology, notably during late schizogony and subsequent invasion of merozoites into host RBCs, we identified this protein as a possible molecular target of these active hybrids. In silico interaction analysis indicated that 7l and 7r stably interact with the catalytically active ATP-binding pocket of PfCDPK1, by the formation of energetically favorable H-bonds. Furthermore, in vitro Microscale Thermophoresis and kinase assays with recombinant PfCDPK1 demonstrated that the active hybrids interact with and inhibit the kinase activity, thus presumably responsible for the parasite growth inhibition. Interestingly, 7l and 7r showed no inhibitory effect on the human kinases, indicating that they are selective for the parasite kinase. Conceivably, we report the antiplasmodial potential of novel kinase targeting bio-conjugates, a step towards developing pan-kinase inhibitors, which is a prerequisite for cross-stage anti-malarial protection. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=115 SRC="FIGDIR/small/498981v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@113574borg.highwire.dtl.DTLVardef@c81a33org.highwire.dtl.DTLVardef@1301d22org.highwire.dtl.DTLVardef@1c8cac5_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2022

P2RX7 inhibition reduces breast cancer induced osteolytic lesions - implications for bone metastasis

Breast cancer metastasis to bone is a major contributor to morbidity and mortality in patients and remains an unmet clinical need. Purinergic signalling via the P2X7 receptor (P2RX7) in the primary tumour microenvironment is associated with progression of several cancers. It has also now become evident that intra-tumoural hypoxia facilitates cancer metastasis and reduces patient survival. In this study, we present data suggesting that hypoxia regulates the expression of P2RX7 in the primary tumour microenvironment; and importantly, inhibition with a selective antagonist (10mg/kg A740003) increased cancer cell death via apoptosis in a E0771/C57BL-6J syngeneic murine model. Furthermore, micro-computed tomography demonstrated reduced number of osteolytic lesions and lesion area following P2RX7 inhibition in absence of overt metastases by decreasing osteoclast numbers. We also demonstrate that activation of P2RX7 plays a role in the secretion of extracellular vesicles (EVs) from breast cancer cells. Mass-spectrometric analyses showed a distinct protein signature for EVs derived from hypoxic compared with normoxic cancer cells which elicit specific responses in bone cells that are associated with pre-metastatic niche formation. Thus, inhibiting P2RX7 provides a novel opportunity to preferentially target the hypoxic breast cancer cells preventing tumour progression and subsequent metastasis to bone

cancer biology↗

bioRxiv2021

CaPti1/CaERF4 module positively regulates pepper resistance to bacterial wilt disease through coupling enhanced immunity and dehydration tolerance

Bacterial wilt, a severe disease that affects over 250 plant species, is caused by Ralstonia solanacearum through vascular system blockade. Although both plant immunity and dehydration tolerance might contribute to disease resistance, whether and how they are related are still unclear. Herein, we provide evidence that immunity against R. solanacearum and dehydration tolerance are coupled and regulated by CaPti1-CaERF4 module. By expression profiling, virus-induced gene silencing in pepper and overexpression in Nicotiana benthamiana, both CaPti1 and CaERF4 were upregulated by R. solanacearum inoculation, dehydration stress and exogenously applied ABA. They in turn phenocopied with each other in promoting pepper resistance to bacterial wilt not only by activating HR cell death and SA-dependent CaPR1, but also by activating dehydration tolerance related CaOSM1 and CaOSR1, and stomata closure to reduce water loss in ABA signaling dependent manner. Yeast-two hybrid assay showed that CaERF4 interacts with CaPti1, which was confirmed by co-immunoprecipitation and pull-down assays. Chromatin immunoprecipitation and electrophoretic mobility shift assay showed that, upon R. solanacearum inoculation, CaPR1, CaOSM1 and CaOSR1 were directly targeted and positively regulated by CaERF4 via binding GCC-box or DRE-box, which was potentiated by CaPti1. In addition, our data indicate that CaPti1-CaERF4 complex might act downstream ABA signaling, since the exogenously applied ABA did not alter stomata aperture regulated by CaPti1-CaERF4 module. Importantly, CaPti1-CaERF4 module was found also acts positively in pepper growth and response to dehydration stress. Collectively, the results suggest that immunity and dehydration tolerance are coupled and positively regulated by CaPti1-CaERF4 in pepper plants to enhance resistance against R. solanacearum. SummaryPepper immunity and dehydration tolerance are coupled and regulated by the CaPti1-CaERF4 module partially in a way related to ABA signaling and stomata closure.

physiology↗

bioRxiv2021

Signatures of Brain Network Alteration in Psychogenic Non-Epileptic Seizures: A Rest-EEG Study Based on Power Spectral Density and Phase Lag Index

The main challenge in the clinical assessment of Psychogenic Non-Epileptic Seizures (PNES) is the lack of an electroencephalographic marker in the electroencephalography (EEG) readout. Although decades of EEG studies have focused on detecting cortical brain function underlying PNES, the principle of PNES remains poorly understood. To address this problem, electric potentials generated by large populations of neurons were collected during the resting state to be processed after that by Power Spectrum Density (PSD) for possible analysis of PNES signatures. Additionally, the integration of distributed information of regular and synchronized multi-scale communication within and across inter-regional brain areas has been observed using functional connectivity tools like Phase Lag Index (PLI) and graph-derived metrics. A cohort study of 20 PNES and 19 Healthy Control subjects (HC) were enrolled. The major finding is that PNES patients exhibited significant differences in alpha-power spectrum in brain regions related to cognitive operations, attention, working memory, and movement regulation. Noticeably, we observed that there exists an altered oscillatory activity and a widespread inter-regional phase desynchronization. This indicates changes in global efficiency, node betweenness, shortest path length, and small worldness in the delta, theta, alpha, and beta frequency bands. Finally, our findings look into new evidence of the intrinsic organization of functional brain networks that reflects a dysfunctional level of integration of local activity across brain regions, which can provide new insights into the pathophysiological mechanisms of PNES.

neuroscience↗