Host Defense Responses Research Articles

Analysis of the serum proteome profile of wild stump-tailed macaques (Macaca arctoides) seropositive for Zika virus antibodies in Thailand

Zika virus (ZIKV) is a member of the Flaviviridae virus family and poses a significant global health concern. ZIKV is transmitted by Aedes mosquitoes, and it has been implicated in various neurological conditions associated with fetal brain development. ZIKV has two transmission cycles: a sylvatic cycle in which nonhuman primates are infected via arboreal mosquito bites, and an interhuman (urban) cycle in which the virus is transmitted among primates by Aedes mosquitoes. ZIKV was first discovered in wild macaques, and the danger posed by the virus is increased due to the close proximity between humans and wild animals in modern society. However, data regarding the extent and role of infection in nonhuman primates are limited. Thus, there is an urgent need for improved surveillance, diagnostic methods, and public health interventions to effectively combat ZIKV transmission and its associated health impacts in Southeast Asia. In this study, we used a proteomics and bioinformatics approach to profile serum proteins in wild stump-tailed macaques seropositive for neutralizing antibodies against ZIKV. A total of 9,532 total proteins were identified, and 338 differentially expressed proteins were identified between naïve and seropositive animals. A total of 52 important proteins were used to construct a serum proteomic profile. These 52 important proteins were associated with immune and inflammatory responses (36.54%), neurological damage (23.08%), viral activities (21.15%), the apoptosis signaling pathway (9.61%), and other pathways (9.61%). Our proteomic profile identified proteins that inhibit the apoptosis pathway, intracellular resource competition with the virus, and neurological damage due to ZIKV and the host immune and defense responses.

Role of mucous cells in the defence system of the cnidarian Actinia equina (Linnaeus, 1758): The keystone of evolution

AbstractCnidarians are the first phylum of metazoans to exhibit a functional mucus layer. In evolution, mucous cells perform the classical secretory function of mucus and act as sentinels for external insults, particularly in mammals. However, this topic has not been much analysed in the lower metazoans. This study aims to investigate the role of mucous cells in Actinia equina (Anthozoa, Hexacorallia) (Linnaeus, 1758) by using confocal microscopy and bioinformatics. The results show colocalization of Toll‐like receptor 2 (TLR2) and Mucin2 (MUC2) on these cells, suggesting a crosstalk between defence response and mucus secretion in cnidarians. Furthermore, the presence of TLR2 on the surface of mucous cells suggests their involvement in host defence responses, as occurs in vertebrates. Moreover, through in silico analysis, we confirmed the presence of orthologous genes for the tested antibodies, providing additional evidence to support our results from an evolutionary perspective. These data suggest that mucous cells play a defensive role throughout evolution, helping us understand how these cells have developed and adapted across phylogenesis. This information also provides new insights into the defensive strategies of invertebrates and clarifies their evolutionary history.

Functional Role of Hepatitis C Virus NS5A in the Regulation of Autophagy

Many types of RNA viruses, including the hepatitis C virus (HCV), activate autophagy in infected cells to promote viral growth and counteract the host defense response. Autophagy acts as a catabolic pathway in which unnecessary materials are removed via the lysosome, thus maintaining cellular homeostasis. The HCV non-structural 5A (NS5A) protein is a phosphoprotein required for viral RNA replication, virion assembly, and the determination of interferon (IFN) sensitivity. Recently, increasing evidence has shown that HCV NS5A can induce autophagy to promote mitochondrial turnover and the degradation of hepatocyte nuclear factor 1 alpha (HNF-1α) and diacylglycerol acyltransferase 1 (DGAT1). In this review, we summarize recent progress in understanding the detailed mechanism by which HCV NS5A triggers autophagy, and outline the physiological significance of the balance between host–virus interactions.

Screening Surface-Defective Graphene Quantum Dots: Promoting Plant Growth and Combating Phytovirus.

Reduced graphene quantum dots (r-GQD), graphene oxide quantum dots (GOQD), and carboxylated graphene quantum dots (C-GQD) are screened to promote tobacco growth and combat tobacco mosaic virus (TMV). First, a 21-day foliar exposure is employed to explore GQDs' impacts on N. benthamiana. Surface-defective GOQD and C-GQD are screened out to facilitate N. benthamiana uptake through leaf stomata, and to promote seedlings of differently leaf ages to various degrees at different concentrations after different durations of foliar exposure. Specially, compared to the ddH2O treatment, GOQD/C-GQD at 400 mg L-1 increase biomass by 44%/68%, increase chlorophyll content by 43%/54% and up-regulate the expression of growth-related genes NtLRX1, CycB, and NtPIP1 by more than two-fold. Second, different from the transient inhibition shown by r-GQD and the TMV enhancement shown by GOQD, C-GQD can directly inactivate TMV infection by inducing TMV aggregation and attachment outside TMV, significantly decreasing TMV replication and hindering TMV spread over 21-day. Specially, C-GQD decreases the transcript abundance of TMV RdRp and TMV CP to 0.11-fold and 0.29-fold, and down-regulates the host defensive response pathways. This work provides a comparative analysis of GQDs with different surface-functionalizations, highlighting C-GQD as a promising nanotechnology tool for promoting plant growth and inactivating phytovirus.

Immunostimulation Signaling via Toll-like Receptor 2 Activation: A Molecular Mechanism of Lactococcus lactis OTG1204 In Vitro and In Vivo

Introduction: The immune system’s defense against pathogens involves innate and adaptive responses, crucial in maintaining overall health. Immunosuppressed states render individuals more susceptible to potential diseases, indicating the need for effective strategies to bolster immune functions. Objectives: Although the immunostimulatory effects of various probiotics have been studied, the specific effects and molecular mechanisms of Lactococcus lactis OTG1204 (OTG1204) remain unknown. In this study, the aim was to investigate the molecular mechanisms of OTG1204 in RAW 264.7 macrophages, the key effector cells of the innate immune system involved in host defense and inflammatory responses. Additionally, in this study, the effects of OTG1204 on cyclophosphamide (CTX)-induced immunosuppression states were investigated, thereby demonstrating its potential as an immune stimulant. Methods: To assess the macrophage activation ability and underlying mechanisms of OTG1204, RAW 264.7 cells were utilized with transfection, enzyme-linked immunosorbent assay, and quantitative real-time PCR analyses. Furthermore, to evaluate the immunostimulatory effects under immunosuppressed conditions, CTX-induced immunosuppression mice model was employed, and analyses were performed using hematoxylin and eosin staining, flow cytometry, and microbiota examination. Results: OTG1204 activated RAW 264.7 macrophages, leading to increased production of nitric oxide, prostaglandin E2, and cytokines. This immune activation was mediated through the upregulation of toll-like receptor 2, which subsequently activated the nuclear factor-κB (NF-kB) and mitogen-activated protein kinase (MAPK)/activator protein 1 (AP-1) pathways, thereby stimulating the immune response. In CTX-treated mice, OTG1204 recovered body weight, spleen, and mesenteric lymph node indices, and natural killer cell activity. It re-established populations of innate and adaptive immune cells and activated T cells to secrete cytokines. We also examined the gut barrier integrity and microbiota composition to assess OTG1204’s impact on intestinal health, as these factors play a significant role in immune enhancement. OTG1204 enhanced gut barrier integrity by upregulating mucin 2 and tight junction proteins and modulated the gut microbiota by restoring the Firmicutes/Bacteroidetes balance and reducing the abundance of Actinobacteria and Tenericutes. Conclusion: These results suggest that OTG1204 may serve as an effective probiotic for immune enhancement and gut health management by targeting the NF-κB and MAPK/AP-1 pathways, with minimal side effects.

Differential regulation of glucosinolate-myrosinase mediated defense determines host-aphid interaction in Indian mustard Brassica juncea L.

India's oilseed economy falls short of self-sufficiency and is supplemented by huge imports every year. Increasing national productivity of the major oilseeds is confronted with yield losses due to diverse biotic and abiotic stresses. The productivity of Indian mustard (Brassica juncea Linnaeus), belonging to the family Brassicaceae, is significantly reduced due to damage caused by mustard aphids (Lipaphis erysimi Kaltenbach, Hemiptera: Aphididae). Rapid colonization by the nymphs makes it difficult to protect the crop through agrochemicals. Aphids release effector molecules to modulate the host-defence responses. Glucosinolates (GSLs) extensively found in Brassicaceae family, are hydrolysed by myrosinase into toxic compounds that deter herbivore insects. Here, we investigated the differential activation of the glucosinolate-myrosinase pathway in mustard manifesting susceptibility and resistance to different aphid species. Mustard plants were challenged by two different aphid species mustard aphid and cowpea aphid (Aphis craccivora Koch, Hemiptera: Aphididae) leading to complete host-susceptibility in one case and resistance in the other, respectively. Differential regulation of the GSL biosynthetic pathway and myrosinase activity was assessed by gene expression study and ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC- QToF-ESL-MS). Gene expression study identified selective transcriptional attenuation of the key GSL biosynthetic and myrosinase gene in mustard when challenged with mustard aphid. In contrary, the activation of GSL biosynthetic genes in conjunction with myrosinase at the transcriptional level was profound in mustard, when challenged with cowpea aphid. UPLC-MS analysis showed higher turnover in the hydrolysis of glucosinolates by myrosinase which led to concomitant generation of glucose as byproduct in response to cowpea aphid in mustard plants. GSL-myrosinase pathway is specifically attenuated by the successful aphid species in mustard and thus plays a pivotal role in determining the outcome of the B. juncea-aphid interaction. The results open up a new genetic modification strategy for developing resistance against aphids.

PGLYRP-1 mediated intracellular peptidoglycan detection promotes mucosal protection.

Peptidoglycan recognition proteins (PGRPs or PGLYRPs) are implicated in the control of the intestinal microbiota; however, molecular requirements for peptidoglycan (PGN) binding and receptor signaling mechanisms remain poorly understood. We identified PGLYRP-1 as a receptor for the disaccharide motif of lysine N-acetylglucosamine N-acetylmuramic tripeptide (GMTriP-K) with a newly constructed PGN microarray. Surprisingly, PGLYRP-1 was required for innate immune activation of macrophages by GMTriP-K but not N-acetylglucosamine N-acetylmuramic dipeptide (GMDiP) or muramyl dipeptide (MDP). In macrophages, intracellular PGLYRP-1 complexed with NOD2 and GEF-H1, both of which were required for GMTriP-K-regulated gene expression. PGLYRP-1 localized to the endoplasmic reticulum and interacted at the Golgi with NOD2 upon GMTriP-K stimulation. PGLYRP-1 upregulation and its dependent gene expression signatures were induced in both mouse intestinal inflammation and human ulcerative colitis. Importantly, PGLYRP-1 activation by GMTriP-K resulted in innate immune activation and protection of mice from colitis. Our results show that PGLYRPs can function as intracellular PGN pattern recognition receptors for the control of host defense responses in the intestine.

Comparative transcriptome analysis revealed host defense responses in endosymbiotic gill of Bathymodiolus mussels inhabiting cold seeps and hydrothermal vents

Comparative transcriptome analysis revealed host defense responses in endosymbiotic gill of Bathymodiolus mussels inhabiting cold seeps and hydrothermal vents

New persistent plant RNA virus carries mutations to weaken viral suppression of antiviral RNA interference.

Persistent plant viruses are widespread in natural ecosystems. However, little is known about why persistent infection with these viruses may cause little or no harm to their host. Here, we discovered a new polerovirus that persistently infected wild rice plants by deep sequencing and assembly of virus-derived small-interfering RNAs (siRNAs). The new virus was named Rice tiller inhibition virus 2 (RTIV2) based on the symptoms developed in cultivated rice varieties following Agrobacterium-mediated inoculation with an infectious RTIV2 clone. We showed that RTIV2 infection induced antiviral RNA interference (RNAi) in both the wild and cultivated rice plants as well as Nicotiana benthamiana. It is known that virulent virus infection in plants depends on effective suppression of antiviral RNAi by viral suppressors of RNAi (VSRs). Notably, the P0 protein of RTIV2 exhibited weak VSR activity and carries alanine substitutions of two amino acids broadly conserved among diverse poleroviruses. Mixed infection with umbraviruses enhanced RTIV2 accumulation and/or enabled its mechanical transmission in N. benthamiana. Moreover, replacing the alanine at either one or both positions of RTIV2 P0 enhanced the VSR activity in a co-infiltration assay, and RTIV2 mutants carrying the corresponding substitutions replicated to significantly higher levels in both rice and N. benthamiana plants. Together, our findings show that as a persistent plant virus, RTIV2 carries specific mutations in its VSR gene to weaken viral suppression of antiviral RNAi. Our work reveals a new strategy for persistent viruses to maintain long-term infection by weak suppression of the host defence response.

Bursaphelenchus xylophilus Venom Allergen-Like Protein BxVAP1, Triggering Plant Defense-Related Programmed Cell Death, Plays an Important Role in Regulating Pinus massoniana Terpene Defense Responses.

Bursaphelenchus xylophilus (pine wood nematode, PWN), a migratory plant-parasitic nematode, acts as an etiological agent, inflicting considerable damage to pine forests worldwide. Plant immunity constitutes a crucial factor in resisting various pathogenic invasions. The primary defensive responses of host pines against PWN infection encompass terpene accumulation, defense response-related gene expression, and programmed cell death. Venom allergen-like proteins (VAPs), as potential effectors, are instrumental in facilitating the successful colonization of PWNs. In this study, we investigated the inhibition of B. xylophilus VAP (BxVAP1) expression by RNA interference in vitro. Following BxVAP1 silencing, the reproduction rate and migration rate of the PWN population in Pinus massoniana decreased, the expression of the α-pinene synthase gene was induced, other terpene synthase and pathogenesis-related genes were inhibited and delayed, the peak times and levels of terpene-related substances were changed, and the degree of cavitation in P. massoniana was diminished. Transient expression of BxVAP1 in Nicotiana benthamiana revealed that BxVAP1 was expressed in both the cell membrane and nucleus, inducing programmed cell death and the expression of pathogen-associated molecular pattern-triggered immunity marker genes (NbAcre31 and NbPTI5). This study is the first to demonstrate that silencing the BxVAP1 gene affects host defense responses, including terpenoid metabolism in P. massoniana, and that BxVAP1 can be recognized by N. benthamiana as an effector to trigger its innate immunity, expanding our understanding of the parasitic mechanism of B. xylophilus.

Type I IFN Induces TCR-dependent and -independent Antimicrobial Responses in γδ Intraepithelial Lymphocytes.

Intraepithelial lymphocytes (IELs) expressing the TCRγδ survey the intestinal epithelium to limit the invasion of microbial pathogens. The production of type I IFN is a central component of an antiviral immune response, yet how these proinflammatory cytokines contribute to γδ IEL effector function remains unclear. Based on the unique activation status of IELs and their ability to bridge innate and adaptive immunity, we investigated the extent to which type I IFN signaling modulates γδ IEL function. Using an ex vivo culture model, we find that type I IFN alone is unable to drive IFN-γ production, yet low-level TCR activation synergizes with type I IFN to induce IFN-γ production in murine γδ IELs. Further investigation into the underlying molecular mechanisms of costimulation revealed that TCRγδ-mediated activation of NFAT and JNK is required for type I IFN to promote IFN-γ expression in a STAT4-dependent manner. Whereas type I IFN rapidly upregulates antiviral gene expression independent of a basal TCRγδ signal, neither tonic TCR triggering nor the presence of a TCR agonist was sufficient to elicit type I IFN-induced IFN-γ production invivo. However, bypassing proximal TCR signaling events synergized with IFNAR/STAT4 activation to induce γδ IEL IFN-γ production. These findings indicate that γδ IELs contribute to host defense in response to type I IFN by mounting a rapid antimicrobial response independent of TCRγδ signaling, and may produce IFN-γ in a TCR-dependent manner under permissive conditions.

RNA:DNA triplexes: a mechanism for epigenetic communication between hosts and microbes?

Molecular communication between host and microbe is mediated by the transfer of many different classes of macromolecules. Recently, the trafficking of RNA molecules between organisms has gained prominence as an efficient way to manipulate gene expression via RNA interference (RNAi). Here, we posit a new epigenetic control mechanism based on triple helix (triplex) structures comprising nucleic acids from both host and microbe. Indeed, RNA:DNA triplexes are known to regulate gene expression in humans, but it is unknown whether interkingdom triplexes are formed either to manipulate host processes during pathogenesis or as a host defense response. We hypothesize that a fraction of the extracellular RNAs commonly released by microbes (e.g., bacteria, fungi, and protists) and their hosts form triplexes with the genome of the other species, thereby impacting chromatin conformation and gene expression. We invite the field to consider interkingdom triplexes as unexplored weaponry in the arms race between host and microbe.

Retention of ES cell-derived 129S genome drives NLRP1 hypersensitivity and transcriptional deregulation in Nlrp3tm1Flv mice.

Immune response genes are highly polymorphic in humans and mice, with heterogeneity amongst loci driving strain-specific host defence responses. The inadvertent retention of polymorphic loci can introduce confounding phenotypes, leading to erroneous conclusions, and impeding scientific advancement. In this study, we employ a combination of RNAseq and variant calling analyses to identify a substantial region of 129S genome, including the highly polymorphic Nlrp1 locus, proximal to Nlrp3, in one of the most commonly used mouse models of NLRP3 deficiency (Nlrp3tm1Flv). We show that the presence of the Nlrp1129S locus leads to an increase in NLRP1B protein expression, and a sensitising of Nlrp3tm1Flv macrophages to NLRP1 inflammasome activation, independent of NLRP3 deficiency. Retention of 129S genome further leads to protein sequence differences and altered gene regulation across multiple cell types, including of the key tissue-resident macrophage marker, TIM4. Using alternative models of NLRP3 deficiency, including a previously undescribed conditional Nlrp3 allele enabling precise temporal and cell-type specific control over Nlrp3 deletion, we further show that NLRP3 contributes to Talabostat-driven IL-1β release. Our study also establishes a generic framework to identify functionally relevant SNPs and assess genomic contamination in transgenic mice using RNAseq data. This allows for unambiguous attribution of phenotypes to the target gene and advances the precision and reliability of research in the field of host defence responses.

TRPA1 Influences Staphylococcus aureus Skin Infection in Mice and Associates with HIF-1a and MAPK Pathway Modulation.

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a major public health burden. Emerging antibiotic resistance has heightened the need for new treatment approaches for MRSA infection such as developing novel antimicrobial agents and enhancing the host's defense response. The thermo-ion channels Transient Receptor Potential (TRP-) A1 and V1 have been identified as modulators of S. aureus quorum sensing in cell culture models. However, their effects on in vivo infection control are unknown. In this study, we investigated the therapeutic effect of natural TRP ion channel inhibitors on MRSA skin infection in mice. While deletion of TRPV1 did not affect lesion size or inflammatory markers, TRPA1-/- mice demonstrated significantly reduced infection severity and abscess size. Treatment with natural inhibitors of TRPA1 with or without blockade of TRPV1 also reduced abscess size. Tissue transcriptomic data coupled with immunohistochemistry revealed that TRPA1 inhibition impacted heat shock protein expression (HSP), modulated the HIF-1a and MAPK pathways, and reduced IL4 expression. Additionally, metabolomics data showed an impact on purine and glycosaminoglycan pathways. Multi-omic integration of transcriptomic and metabolic data revealed that diacylglycerol metabolism was the likely bridge between metabolic and immunological impacts. Our findings suggest that TRPA1 antagonism could provide a promising and cost-effective therapeutic approach for reducing the severity of MRSA infection, and presents a novel underlying molecular mechanism.

Human coronaviruses activate and hijack the host transcription factor HSF1 to enhance viral replication

Organisms respond to proteotoxic-stress by activating the heat-shock response, a cellular defense mechanism regulated by a family of heat-shock factors (HSFs); among six human HSFs, HSF1 acts as a proteostasis guardian regulating severe stress-driven transcriptional responses. Herein we show that human coronaviruses (HCoV), both low-pathogenic seasonal-HCoVs and highly-pathogenic SARS-CoV-2 variants, are potent inducers of HSF1, promoting HSF1 serine-326 phosphorylation and triggering a powerful and distinct HSF1-driven transcriptional-translational response in infected cells. Despite the coronavirus-mediated shut-down of the host translational machinery, selected HSF1-target gene products, including HSP70, HSPA6 and AIRAP, are highly expressed in HCoV-infected cells. Using silencing experiments and a direct HSF1 small-molecule inhibitor we show that, intriguingly, HCoV-mediated activation of the HSF1-pathway, rather than representing a host defense response to infection, is hijacked by the pathogen and is essential for efficient progeny particles production. The results open new scenarios for the search of innovative antiviral strategies against coronavirus infections.

Virulent Effector Hasp155 of Puccinia striiformis f. sp. tritici Suppresses Plant Immunity and Promotes Fungus Infection.

As a kind of obligate biotrophic fungus, Puccinia striiformis f. sp. tritici (Pst) secretes vast effectors via haustoria to host cells during the infection to inhibit host defense responses and promote fungal invasion. In this study, based on the completion of genome sequencing and haustorial transcriptome sequencing of Pst, we identified a Pst effector (Hasp155) that is significantly induced in the early stage of Pst infection to wheat. The 18 N-terminal amino acids of Hasp155 encoded a signal peptide with a secretory function. Transient expression of Hasp155 in Nicotiana benthamiana inhibited Bax-induced cell death as well as chitin-triggered callose deposition and defense-related gene expression. Moreover, delivery of the Hasp155 protein into wheat cells via type three secretion systems (TTSS) led to reduced plant immunity to nonpathogenic bacteria and to the avirulent Pst race with decreased H2O2 accumulation and promoted Pst development. Furthermore, transgenic overexpression of Hasp155 significantly renders wheat resistance susceptible, resulting in a decreased defense response and increased Pst pathogenicity. Overall, these results indicate that Hasp155 is an important effector of Pst pathogenicity by suppressing plant immunity.

The complement system: A key player in the host response to infections.

Infections are one of the most significant healthcare and economic burdens across the world as underscored by the recent coronavirus pandemic. Moreover, with the increasing incidence of antimicrobial resistance, there is an urgent need to better understand host-pathogen interactions to design effective treatment strategies. The complement system is a key arsenal of the host defense response to pathogens and bridges both innate and adaptive immunity. However, in the contest between pathogens and host defense mechanisms, the host is not always victorious. Pathogens have evolved several approaches, including co-opting the host complement regulators to evade complement-mediated killing. Furthermore, deficiencies in the complement proteins, both genetic and therapeutic, can lead to an inefficient complement-mediated pathogen eradication, rendering the host more susceptible to certain infections. On the other hand, overwhelming infection can provoke fulminant complement activation with uncontrolled inflammation and potentially fatal tissue and organ damage. This review presents an overview of critical aspects of the complement-pathogen interactions during infection and discusses perspectives on designing therapies to mitigate complement dysfunction and limit tissue injury.

Vacuolar recruitment of retromer by a SNARE complex enables infection-related trafficking in rice blast.

The retromer complex is a conserved sorting machinery that maintains cellular protein homeostasis by transporting vesicles containing cargo proteins to defined destinations. It is known to sort proteins at the vacuole membranes for retrograde trafficking, preventing their degradation in the vacuole. However, the detailed mechanism of retromer recruitment to the vacuole membrane has not yet been elucidated. Here, we show that the vacuolar SNARE complex MoPep12-MoVti1-MoVam7-MoYkt6 regulates retromer-mediated vesicle trafficking by recruiting the retromer to the vacuole membrane, which promotes host invasion in Magnaporthe oryzae. Such recruitment is also essential for the retrieval of the autophagy regulator MoAtg8 and enables appressorium-mediated host penetration. Furthermore, the vacuolar SNARE subunits are involved in suppressing the host defense response by regulating the deployment of retromer-MoSnc1-mediated effector secretion. Altogether, our results provide insights into the mechanism of vacuolar SNAREs-dependent retromer recruitment which is necessary for pathogenicity-related membrane trafficking events in the rice blast fungus.

Atg16l2 augments Nlrc4 inflammasome activation by facilitating NAIPs-NLRC4 association.

As cytoplasmic protein complexes that are pivotal for innate immunity, inflammasomes act primarily through the detection of pathogen- or danger-associated molecular patterns. Nucleotide oligomerisation domain-like receptor family and caspase activation recruitment domain-containing protein 4 (NLRC4) inflammasomes identify and eliminate intracellular pathogens, a process contingent on the ligand-recognition capabilities of neuronal apoptosis inhibitory proteins (NAIPs). Upon detection of specific molecules indicative of intracellular infection, NAIPs discern distinct pathogenic components and subsequently transmit signals to NLRC4, thus initiating their activation and triggering an inflammatory response. However, the mechanisms underlying NLRC4 inflammasome remain unclear. In this study, we elucidated the critical role of ATG16L2 in activating the NLRC4 inflammasome. ATG16L2-deficient macrophages exhibited reduced NLRC4 inflammasome activation, characterised by decreased oligomerisation of apoptosis-associated speck-like protein containing a CARD and attenuated cleavage of Pro-caspase-1, Pro-IL-1β and gasdermin D. Co-immunoprecipitation assays revealed an interaction between ATG16L2 and NAIPs. Furthermore, ATG16L2 enhanced the association between NAIPs and NLRC4 by binding to NAIPs. For ATG16L2-knockout mice infected with Salmonella typhimurium, pathogen clearance and survival rates markedly decreased. Collectively, our findings suggest that ATG16L2 is a significant modulator of the innate immune system, influencing the activity of the NLRC4 inflammasome and the host's defensive response to intracellular pathogens.

Transcriptomic Approach for Investigation of Solanum spp. Resistance upon Early-Stage Broomrape Parasitism.

Tomato (Solanum lycopersicum) is a major horticultural crop of high economic importance. Phelipanche and Orobanche genera (broomrapes) are parasitic weeds, constituting biotic stressors that impact tomato production. Developing varieties with tolerance to broomrapes has become imperative for sustainable agriculture. Solanum pennellii, a wild relative of cultivated tomato, has been utilized as breeding material for S. lycopersicum. In the present study, it is the first time that an in-depth analysis has been conducted for these two specific introgression lines (ILs), IL6-2 and IL6-3 (S. lycopersicum X S. pennellii), which were employed to identify genes and metabolic pathways associated with resistance against broomrape. Comparative transcriptomic analysis revealed a multitude of differentially expressed genes (DEGs) in roots, especially in the resistant genotype IL6-3, several of which were validated by quantitative PCR. DEG and pathway enrichment analysis (PEA) revealed diverse molecular mechanisms that can potentially be implicated in the host's defense response and the establishment of resistance. The identified DEGs were mostly up-regulated in response to broomrape parasitism and play crucial roles in various processes different from strigolactone regulation. Our findings indicate that, in addition to the essential role of strigolactone metabolism, multiple cellular processes may be involved in the tomato's response to broomrapes. The insights gained from this study will enhance our understanding and facilitate molecular breeding methods regarding broomrape parasitism. Moreover, they will assist in developing sustainable strategies and providing alternative solutions for weed management in tomatoes and other agronomically important crops.