Secondary Response Research Articles

The macrophage migration inhibitory factor/CD74 axis in traumatic spinal cord injury: lessons learned from animal and human studies.

Traumatic spinal cord injury (SCI) is a severe condition leading to long-term impairment of motor, sensory, and autonomic functions. Following the initial injury, a series of additional events is initiated further damaging the spinal cord. During this secondary injury phase, both an inflammatory and immune modulatory response are triggered that have damaging and anti-inflammatory properties, respectively. The proinflammatory cytokine macrophage migration inhibitory factor (MIF) and its receptor CD74 have been extensively studied in traumatic SCI. MIF expression is increased in spinal cord tissue after experimental SCI, mainly in astrocytes and microglia, as well as in the plasma of SCI patients. Functionally, MIF and CD74 were shown to regulate astrocyte viability, proliferation and cholesterol metabolism, microglia migration, and neuronal viability. Moreover, inhibition of the MIF/CD74 axis improved the functional recovery of SCI animals. We provide a detailed overview of studies analyzing the role of MIF and CD74 in traumatic SCI. We describe results from animal studies, using rat and mouse models for SCI, and human studies. Furthermore, we propose a new path for investigation, focused on B cells, that might lead to a better understanding of how MIF and CD74 contribute to the secondary injury cascade following traumatic SCI.

Aeroelastic Effects in Supersonic Shock-Turbulent Boundary Layer Interaction over Flexible Panels

The dynamic coupling between a Mach 1.94 shock wave/turbulent boundary layer interaction (SBLI) and a flexible panel is investigated. High-order numerical simulations are performed for distinctly different dynamic panel motions and rigid snapshots of their maximum deflected shape. They are compared with a baseline interaction over a rigid planar wall. The panel’s dynamic surface motions were obtained from the Air Force Research Laboratory (AFRL) wind tunnel experiments. The primary aim of the study was to determine whether there were any differences in the flow pressure loading on the compliant panel due to the various rigid and dynamic deformations considered. The results show that the examined panel deformations increase the SBLI size near the panel midpoint, where the deformation amplitude tends to be the largest. Relative to the rigid planar case, the examined surface deformations cause the mean-flow high-pressure surface loading caused by the impinging shock wave to shift downstream along the compliant panel midspan, albeit by a small amount. The spectrogram of the dynamic deformation and the flow surface pressure response suggests that the two are strongly coupled at the dominant (primary) mode but less so at the secondary modes. Although the primary mode frequencies overlap, they do not exactly match, with the pressure response frequency always being slightly higher in all three cases. The rigid deformations did not enhance the pressure power content at the SBLI. However, pre-SBLI and near the panel leading edge, the pressure power spectrum weakly increased throughout the resolved frequency range and overlapped with the onset of the amplification found in the dynamic deformation cases. Post-SBLI, the rigid deformations cause a weak enhancement at frequencies below 1 kHz, which closely match the dominant and secondary pressure response frequencies obtained in the dynamic cases.

Rescuing pathogen-specific memory B-cell from PBMC of prior Zika virus-infected individuals

Immunological memory, a fundamental immune system mechanism, is instrumental in long-term protection. Successful vaccines can elicit and sustain immunological memory against pathogens for the long term. Memory B cells (MBC) are key players in secondary responses due to their longevity and rapid differentiation into high-affinity antibody-secreting cells upon second antigen exposure. However, the availability of circulating MBCs is limited. Here we describe a protocol, which presents a straightforward and practical method for activating and expanding Zika virus (ZIKV) specific MBC. PBMCs collected from individuals who had been infected with ZIKV two years prior were cultured by supplementing with IL-2 and R848, a TLR-7/8 agonist, and then pulsed with inactivated virus. After seven days, this stimulation led to a notable rise in virus-specific functional MBC, as evidenced by a significant increase in the production of anti-ZIKV IgG. Importantly, the ZIKV pulse did not induce changes in the PBMC culture of individuals without a history of ZIKV infection. These findings demonstrate that virus-specific MBC can be expanded in vitro, even using PBMC cultures from individuals infected years before. Therefore, our protocol is a practical and effective tool for studies that require a larger number of human MBCs from previously infected individuals that are functional and specific to the pathogen under investigation.

A R2R3-MYB transcription factor, FeR2R3-MYB, positively regulates anthocyanin biosynthesis and drought tolerance in common buckwheat (Fagopyrum esculentum)

The R2R3-MYB transcription factors (TFs) play a crucial role in regulating plant secondary metabolism and abiotic stress responses, yet they are still poorly understood in common buckwheat (Fagopyrum esculentum), a valuable minor grain crop resource. In this study, a candidate gene, FeR2R3-MYB, was cloned from the anthocyanin-rich common buckwheat variety ‘QZZTQ’. FeR2R3-MYB was found to contain two MYB DNA-binding domains and be located at the nucleus with transcriptional activation activity. Molecular analysis indicated that FeR2R3-MYB is predominantly expressed in flowering tissue and is highly responsive to environmental factors such as light, drought, and cold. In addition, the promoter of FeR2R3-MYB showed a positive correlation with fragment length. Further functional analysis suggested that FeR2R3-MYB not only participates in the anthocyanin biosynthetic pathway by interacting with leucoanthocyanidin reductase (FeLAR), but also enhances drought tolerance in common buckwheat. To sum up, FeR2R3-MYB exhibits positive effects on both pigment production (e.g., anthocyanin) and abiotic stress resistance, providing valuable insights for future research in buckwheat molecular breeding and resource development.

Predictive immunoinformatics reveal promising safety and anti-onchocerciasis protective immune response profiles to vaccine candidates (Ov-RAL-2 and Ov-103) in anticipation of phase I clinical trials.

Onchocerciasis (river blindness) is a debilitating tropical disease that causes significant eye and skin damage, afflicting millions worldwide. As global efforts shift from disease management to elimination, vaccines have become crucial supplementary tools. The Onchocerciasis Vaccine for Africa (TOVA) Initiative was established in 2015, to advance at least one vaccine candidate initially targeting onchocerciasis in infants and children below 5 years of age, through Phase I human trials by 2025. Notably, Ov-RAL-2 and Ov-103 antigens have shown great promise during pre-clinical development, however, the overall success rate of vaccine candidates during clinical development remains relatively low due to certain adverse effects and immunogenic limitations. This study, thus, aimed at predicting the safety and immunogenicity of Ov-RAL-2 and Ov-103 potential onchocerciasis vaccine candidates prior to clinical trials. Advanced molecular simulation models and analytical immunoinformatics algorithms were applied to predict potential adverse side effects and efficacy of these antigens in humans. The analyses revealed that both Ov-RAL-2 and Ov-103 demonstrate favourable safety profiles as toxicogenic and allergenic epitopes were found to be absent within each antigen. Also, both antigens were predicted to harbour substantial numbers of a wide range of distinct epitopes (antibodies, cytokines, and T- Cell epitopes) associated with protective immunity against onchocerciasis. In agreement, virtual vaccination simulation forecasted heightened, but sustained levels of primary and secondary protective immune responses to both vaccine candidates over time. Ov-103 was predicted to be non-camouflageable, as it lacked epitopes identical to protein sequences in the human proteome. Indeed, both antigens were able to bind with high affinity and activate the innate immune TLR4 receptor, implying efficient immune recognition. These findings suggest that Ov-RAL-2 and Ov-103 can induce sufficient protective responses through diverse humoral and cellular mechanisms. Overall, our study provides additional layer of evidence for advancing the clinical development of both vaccine candidates against onchocerciasis.

Collaboration in Contradiction: Self-Adaptive Synergistic ROS Generation and Scavenge Balancing Strategies Used for the Infected Wounds Treatment.

The rational utilization of ROS is key to treating infected wounds. Exogenous ROS can destroy bacterial structures, quickly kill bacteria, and inhibit secondary infections. However, excess ROS at the wound will cause a secondary inflammatory response. Acute infections exacerbate this damage by increasing endogenous ROS, complicating the maintenance of ROS homeostasis. Therefore, regulating the balance of ROS production and scavenging in wounds has emerged as a promising strategy for wound treatment. Conventional ROS balancing platforms are mostly based on the " all for one" strategy of functional superposition and lack self-adaptability and integration. To subvert this conventional strategy, this study proposes a "one for all" self-adaptive integrated photodynamic therapy (PDT)-antioxidant model to actively regulate the ROS balance. A gelatin-hyaluronic acid hydrogel embedded with Se-modified cerium dioxide nanoparticles (Gel-HA-Se@CeO2 NPs) is designed for treating infected wounds. The Se@CeO2 NPs serve both as nanoenzymes and photosensitizers(PS). As nanoenzymes, they exhibit catalase and superoxide dismutase activities, converting hydrogen peroxide and superoxide anions into oxygen. As a PS, it synergizes with oxygen under NIR irradiation to rapidly produce singlet oxygen. Additionally, Se modification enhances the PDT effects by disrupting bacterial antioxidant systems. In vitro and in vivo experiments revealed that the ROS balance platform polarizes M1-type macrophages to M2-type macrophages, altering the wound microenvironment from proinflammatory to prohealing. RNA sequencing revealed that this hydrogel accelerated the reconstruction of the vascular network of the wound by activating the PI3K/AKT pathway and increasing VEGF secretion.This strategy is believed to be beneficial not only for infected wounds but also for treating other conditions that involve the regulation of reactive oxygen species, such as tumors and bacterial infections.

Transcriptome analysis reveals role of transcription factor WRKY70 in early N-hydroxy-pipecolic acid signaling.

N-hydroxy-pipecolic acid (NHP) is a mobile metabolite essential for inducing and amplifying systemic acquired resistance (SAR) following pathogen attack. Early phases of NHP signaling leading to immunity have remained elusive. Here, we report the early transcriptional changes mediated by NHP and the role salicylic acid (SA) plays during this response in Arabidopsis (Arabidopsis thaliana). We show that distinct waves of expression within minutes to hours of NHP treatment include increased expression of WRKY transcription factor genes as the primary transcriptional response, followed by the induction of WRKY-regulated defense genes as the secondary response. Most genes induced by NHP within minutes were SA-dependent, whereas those induced within hours were SA-independent. These data suggest that NHP induces the primary transcriptional response under basal levels of SA and that new SA biosynthesis via ISOCHORISMATE SYNTHASE 1/SA-INDUCTION DEFICIT 2 (ICS1/SID2) is dispensable for inducing the secondary transcriptional response. We demonstrate that WRKY70 is required for the induced expression of a set of genes defining some of the secondary transcriptional response, SAR protection, and NHP-dependent enhancement of ROS production in response to flagellin treatment. Our study highlights the key genes and pathways defining early NHP responses and the role of WRKY70 in regulating NHP-dependent transcription.

Microenvironment‐Responsive Injectable Conductive Hydrogel for Spinal Cord Injury Repair

AbstractSpinal cord injury (SCI) represents a severe neurological condition often coupled with a drastic secondary inflammatory response, which further exacerbates the damage in most cases. Due to their unique electrical and mechanical compatibilities with the spinal cord, the utilization of conductive hydrogels through injection for SCI repair, particularly in scenarios involving non‐uniform and large gaps, has emerged as a promising approach. Herein, leveraging the acidic microenvironment characteristic of acute SCI sites, an injectable conductive hydrogel with pH‐responsive immunoregulation is engineered for SCI repair. Based on the dynamic Schiff base chemistry and covalent photo‐crosslinking, this composite hydrogel, composed of gelatin methacryloyl, oxidized dextran, and MoS2, exhibits adjustable mechanical and conductive properties, enabling a customized match with the natural spinal cord's attributes. Additionally, the incorporation of Wnt5a and its selective release in acidic conditions prompt the immediate suppression of inflammatory factors and enhances neural differentiation and regeneration. In the 2‐mm hemisection mouse SCI model, the optimized conductive hydrogel can effectively bridge the injury gap, establish nerve connections and signal, mitigate inflammatory response, and promoted recovery of mobility. This novel injectable conductive hydrogel system offers a promising advance in therapeutic materials for SCI repair.

Electromyographically controlled prosthetic wrist improves dexterity and reduces compensatory movements without added cognitive load

Wrist function is a top priority for transradial amputees. However, the combined functional, biomechanical, and cognitive impact of using a powered prosthetic wrist is unclear. Here, we quantify task performance, compensatory movements, and cognitive load while three transradial amputees performed a modified Clothespin Relocation Task using two myoelectric prostheses with and without the wrists. The two myoelectric prostheses include a commercial prosthesis with a built-in powered wrist, and a newly developed inexpensive prosthetic wrist for research purposes, called the “Utah wrist”, that can be adapted to work with various sockets and prostheses. For these three participants, task failure rate decreased significantly from 66% ± 12% without the wrist to 39% ± 9% with the Utah wrist. Compensatory forward leaning movements also decreased significantly, from 24.2° ± 2.5 without the wrist to 12.6° ± 1.0 with the Utah wrist, and from 23.6° ± 7.6 to 15.3° ± 7.2 with the commercial prosthesis with an integrated wrist. Compensatory leftward bending movements also significantly decreased, from 20.8° ± 8.6 to 12.3° ± 5.3, for the commercial with an integrated wrist. Importantly, simultaneous myoelectric control of either prosthetic wrist had no significant impact on cognitive load, as assessed by the NASA Task Load Index survey and a secondary detection response task. This work suggests that functional prosthetic wrists can improve dexterity and reduce compensation without significantly increasing cognitive effort. These results, and the introduction of a new inexpensive prosthetic wrist for research purposes, can aid future research and development and guide the prescription of upper-limb prostheses.

Dramatic Reanimation and Spontaneous Re-Canalization of a Fourth Ventricular Hemorrhage: “REVIVE” Phenomenon

Background Intraventricular hemorrhage is a calamitous type of stroke where bleeding into the ventricular system can be defined as: primary, if confined within the ventricles; or secondary, due to intracerebral hemorrhage extending from adjacent parenchyma. Intraventricular blood clot can lead to secondary insult and inflammatory responses that culminates in hydrocephalus as the most common cause of death. Purpose THerein, we report a patient with a high modified Graeb scale and low Glasgow coma scale. She spontaneously recanalized her fourth ventricle, decompressed her reticular activating system with remarkable spontaneous bilateral eye opening, and a consequently experienced a halfway drop in her mGS. Results This is the first reported case of a spontaneous recanalization of 4th ventricle obstruction secondary to IVH without intervention and subsequent dramatic neurological improvement. We believe that the apixaban primarily preserved the liquid state of hemorrhage and her presumed elevated ICP was sufficient to push out the liquified blood in the 4th ventricle into the upper spinal canal , recanalizing the 4th ventricle by continuously creating downward CSF pressure waves. Given the RAS location around the 4th ventricle, we hypothesize spontaneous decompression from the clot lysis triggered the RAS activation with sudden arousal manifested as spontaneous bilateral eyes opening. Hence, we refer to this as the reticular activating system reactivation after ventricular hemorrhage evacuation, or simply the “REVIVE” phenomenon. Conclusion This dramatic improvement from coma to awake state is worthy of recognition for future neurotherapeutic interventions.

Proteomics fingerprinting reveals importance of iron and oxidative stress in Streptomyces scabies-Solanum tuberosum interactions.

The Gram-positive actinobacterium Streptomyces scabies is the major causal agent of potato common scab. The main pathogenicity factor is thaxtomin A, a phytotoxin that causes atypical cell death, although other secondary metabolites have been described to play a role in S. scabies virulence. Despite this, many aspects of the interaction between S. scabies and its primary host Solanum tuberosum L. remain to be elucidated. Intracellular proteins of S. scabies EF-35 grown in the presence of in vitro produced tubers (microtubers) of the Russet Burbank and Yukon Gold potato cultivars were extracted and analysed by electrospray mass spectrometry (ES MS/MS). Based on the results of proteomic analysis, iron quantification by ICP-MS and nitrite quantification using Griess reagent in growth media as well as RT-qPCR analysis of the siderophore pyochelin gene expression were performed in the presence and absence of microtubers. Hydrogen peroxide accumulation was also determined in the nutrient medium used for co-cultivation of bacteria and potato microtubers. Potato microtubers caused an increase in the content of bacterial proteins involved in stress and defense, secondary metabolism, and cell differentiation, as well as secreted proteins. Co-cultivation with potato microtubers induced the accumulation of S. scabies proteins implicated in siderophore pyochelin biosynthesis, nitrite production and oxidative stress perception and response. The increase in the abundance of proteins related to pyochelin biosynthesis was consistent with a significant decrease in the iron content in the culture medium, as well as with induction of expression of pyochelin biosynthesis genes. Elevated nitrite/sulfite reductase protein levels were associated with increased nitrite excretion by S. scabies cells in the presence of host microtubers. The increase in the levels of proteins associated with signaling and oxidative stress response could have been caused by the accumulation of ROS, in particular hydrogen peroxide, detected in the studied system. These findings show that interactions of S. scabies with living potato microtubers induce the production of secondary metabolites, defense responses, and protection from oxidative stress. This study suggests the importance of iron during host - S. scabies interactions, resulting in competition between pathogen and its host.

Dinámica de los receptores de quimioquinas en la membrana celular

Chemokines are chemotactic cytokines that control the migratory patterns and positioning of many cells, including immune cells. Although chemokines were initially considered to be important mediators of acute inflammation, we now know that this complex system of ligands and receptors is essential for the generation of primary and secondary adaptive cellular and humoral immune responses. In addition, they also trigger other biological responses ranging from cell polarization or movement or the prevention of HIV-1 infection. Chemokine-mediated cell activation was believed to be due to the binding of a monomeric chemokine to its monomeric receptor. However, the biology of these mediators is more complex than initially anticipated, as several studies indicate that chemokines dimerize. In addition, the use of new advanced optical imaging techniques have made possible to determine that the receptors also form dimers, homo- and heterodimers, as well as higher order oligomers at the cell surface. These are very dynamic and plastic structures/conformations, influenced by the presence of ligands, the co-expression of other receptors and proteins, the lipid composition of the cell membrane or the environment where cells perform their function. Keywords: Chemokines; Chemokine receptors; Receptor conformation; Molecular dynamics; Signaling

Advancing apple genetics research: Malus coronaria and Malus ioensis genomes and a gene family-based pangenome of native North American apples.

Wild Malus species flourished in North America long before Europeans introduced domesticated apples. Malus coronaria and M. ioensis are native to the mid-western and eastern United States, while M. angustifolia and M. fusca grow in the southeast and west, respectively. They offer disease resistance, climate and soil adaptability, and horticultural traits for apple breeding. However, their utilization remains limited due to insufficient genomic resources and specific genetics. We report high-quality phased chromosome-scale assemblies of M. coronaria and M. ioensis, generated using long-read and conformation capture sequencing. Phylogenetic and synteny analysis indicated high relatedness between these 2 genomes and previously published genome of M. angustifolia, and lower relatedness with M. fusca. Gene family-based pangenome of North American Malus identified 60,211 orthogroups containing 340,087 genes. Genes involved in basic cellular and metabolic processes, growth, and development were core to the existence of these species, whereas genes involved in secondary metabolism, stress response, and interactions with other organisms were accessory and are likely associated with adaptation to specific environments. Structural variation hotspots were mostly overlapping with high gene density. This study offers novel native North American Malus genome resources that can be used to identify genes for apple breeding and understand their evolution and adaptation.

B-cell and plasma cell activation in a mouse model of chronic muscle pain

Fibromyalgia (FM) is a complex chronic musculoskeletal pain disorder with an elusive pathogenesis, with a strong implication of immune interactions. We recently found that IL-5 and the adaptive immune system mediates pain outcomes in fibromyalgia (FM) patients and preclinical models of FM-like chronic widespread pain (CWP). However, there is an active debate if FM/CWP has an autoimmune etiology. Preclinical models of CWP utilize a repeated insult paradigm, which resembles a primary, then secondary response similarly observed in the antibody response in which the subsequent event causes a potentiated pain response. Recent translational studies have implicated immunoglobulins (Ig) and B-cells in FM/CWP pathophysiology. To understand if these are involved in preclinical models of CWP, we performed comprehensive B-cell phenotyping in the bone marrow, circulation, and popliteal (draining) lymph nodes in the two-hit acidic saline model of CWP. We found increased MHC class II-expressing B-cells in peripheral blood, increased activated plasma cells in peripheral blood, and increased memory B-cells in the bone marrow. Interestingly, acidic pH (4.0) injected mice have reduced levels of IgG1, independent of treatment with IL-5. We have demonstrated that the acidic saline model of CWP induces T-cell mediated activation of B-cells, increased active plasma cells, and increased memory B-cells in female mice.

Spatial proteomics and transcriptomics of the maternal-fetal interface in placenta accreta spectrum

In severe Placenta Accreta Spectrum (PAS), trophoblasts gain deep access in the myometrium (placenta increta). This study investigated alterations at the fetal-maternal interface in PAS cases using a systems biology approach consisting of immunohistochemistry, spatial transcriptomics and proteomics. We identified spatial variation in the distribution of CD4+, CD3+ and CD8+ T-cells at the maternal-interface in placenta increta cases. Spatial transcriptomics identified transcription factors involved in promotion of trophoblast invasion such as AP-1 subunits ATF-3 and JUN, and NFKB were upregulated in regions with deep myometrial invasion. Pathway analysis of differentially expressed genes demonstrated that degradation of extracellular matrix (ECM) and class 1 MHC protein were increased in increta regions, suggesting local tissue injury and immune suppression. Spatial proteomics demonstrated that increta regions were characterised by excessive trophoblastic proliferation in an immunosuppressive environment. Expression of inhibitors of apoptosis such as BCL-2 and fibronectin were increased, while CTLA-4 was decreased and increased expression of PD-L1, PD-L2 and CD14 macrophages. Additionally, CD44, which is a ligand of fibronectin that promotes trophoblast invasion and cell adhesion was also increased in increta regions. We subsequently examined ligand receptor interactions enriched in increta regions, with interactions with ITGβ1, including with fibronectin and ADAMS, emerging as central in increta. These ITGβ1 ligand interactions are involved in activation of epithelial–mesenchymal transition and remodelling of ECM suggesting a more invasive trophoblast phenotype. In PAS, we suggest this is driven by fibronectin via AP-1 signalling, likely as a secondary response to myometrial scarring.

Targeting Polyprotein to Design Potential Multiepitope Vaccine against Omsk Hemorrhagic Fever Virus (OHFV) by Evaluating Allergenicity, Antigenicity, and Toxicity Using Immunoinformatic Approaches.

Omsk Hemorrhagic Fever Virus (OHFV) is an RNA virus with a single-stranded, positive-sense genome. It is classified under the Flaviviridae family. The genome of this virus is 98% similar to the Alkhurma hemorrhagic fever virus (AHFV), which belongs to the same family. Cases of the virus have been reported in various regions of Saudi Arabia. Both OHFV and AHFV have similarities in pathogenic polyprotein targets. No effective and licensed vaccines are available to manage OHFV infections. Therefore, an effective and safe vaccine is required that can activate protective immunity against OHFV. The current study aimed to design a multiepitope subunit vaccine against the OHFV utilizing several immunoinformatic tools. The polyprotein of OHFV was selected and potent antigenic, non-allergenic, and nontoxic cytotoxic T-lymphocyte (CTL), helper T-lymphocyte (HTL), and linear B-lymphocyte (LBL) epitopes were chosen. After screening, eight (8) CTL, five (5) HTL, and six (6) B cell epitopes were joined with each other using different linkers. Adjuvant human beta defensin-2 was also linked to the epitopes to increase vaccine antigenic and immunogenic efficiency. The designed vaccine was docked with Toll-like receptor 4 (TLR4) as it activates and induces primary and secondary immune responses against OHFV. Codon optimization was carried out, which resulted in a CAI value of 0.99 and 53.4% GC contents. In addition, the construct was blindly docked to the TLR4 immune receptor and subjected to conformational dynamics simulation analysis to interpret the intricate affinity and comprehend the time-dependent behavior. Moreover, it was predicted that immune responses to the developed vaccine construct reported formation of strong humoral and cellular immune cells. Therefore, the proposed vaccine may be considered in experimental assays to combat OHFV infections. Laboratory experiments for the above predictions are essential in order to evaluate the effectiveness, safety, and protective properties of the subject in question.

The ICF2 gene Zbtb24 specifically regulates the differentiation of B1 cells via promoting heme synthesis

BackgroundLoss-of-function mutations of ZBTB24 cause immunodeficiency, centromeric instability, and facial anomalies syndrome 2 (ICF2). ICF2 is a rare autosomal recessive disorder with immunological defects in serum antibodies and circulating memory B cells, resulting in recurrent and sometimes fatal respiratory and gastrointestinal infections. The genotype–phenotype correlation in patients with ICF2 indicates an essential role of ZBTB24 in the terminal differentiation of B cells.MethodsWe used the clustered regularly interspaced short palindromic repeats (CRISPER)/Cas9 technology to generate B cell specific Zbtb24-deficient mice and verified the deletion specificity and efficiency by quantitative polymerase chain reaction (Q-PCR) and western blotting analyses in fluorescence-activated cell sorting (FACS)-sorted cells. The development, phenotype of B cells and in vivo responses to T cell dependent or independent antigens post immunization were analyzed by flow cytometry and enzyme-linked immunosorbent assay (ELISA). Adoptive transfer experiment in combination with in vitro cultures of FACS-purified B cells and RNA-Seq analysis were utilized to specifically determine the impact of Zbtb24 on B cell biology as well as the underlying mechanisms.ResultsZbtb24 is dispensable for B cell development and maintenance in naive mice. Surprisingly, B cell specific deletion of Zbtb24 does not evidently compromise germinal center reactions and the resulting primary and secondary antibody responses induced by T cell dependent antigens (TD-Ags), but significantly inhibits T cell independent antigen-elicited antibody productions in vivo. At the cellular level, Zbtb24-deficiency specifically impedes the plasma cell differentiation of B1 cells without impairing their survival, activation and proliferation in vitro. Mechanistically, Zbtb24-ablation attenuates heme biosynthesis partially through mTORC1 in B1 cells, and addition of exogenous hemin abrogates the differentiation defects of Zbtb24-null B1 cells.ConclusionsZbtb24 seems to regulate antibody responses against TD-Ags B cell extrinsically, but it specifically promotes the plasma cell differentiation of B1 cells via heme synthesis in mice. Our study also suggests that defected B1 functions contribute to recurrent infections in patients with ICF2.

Efficacy and safety of the S1PR modulator etrasimod in the treatment of moderately to severely active ulcerative colitis during the induction phase: a systematic review and meta-analysis of randomized controlled trials.

The study aims to assess the efficacy and safety of the recently approved S1PR modulator etrasimod in adults with ulcerative colitis during the induction phase through meta-analysis. A systemic search was performed for randomized controlled trials evaluating the efficacy and safety of the S1PR modulator etrasimod using electronic databases PubMed, Embase, the Cochrane Library, Clinical Trials, and the International Clinical Trials Registry Platform. Three studies with 943 patients met the inclusion criteria and were included in this analysis. The study's primary endpoint was the proportion of patients who achieved clinical remission at week 12. Key secondary endpoints included the proportion of patients with clinical response, endoscopic improvement, and histologic remission. The incidence of adverse effects (AEs), serious AEs (SAEs), and AE-related treatment discontinuation were statistically analyzed to determine the safety of etrasimod. This study revealed that etrasimod is superior to placebo at the primary endpoint clinical remission (OR = 3.09, 95% CI: 2.04-4.69), as well as at the secondary endpoints clinical response (OR = 2.56, 95% CI: 1.91-3.43), endoscopic improvement (OR = 2.15, 95% CI: 1.51-3.05), and histologic remission (OR = 3.39, 95% CI: 2.03-5.68). The proportion of patients with TEAE (OR = 1.34, 95% CI: 1.01-1.78) and SAE (OR = 0.77, 95% CI: 0.41-1.43) was similar between the etrasimod and placebo groups. Patients receiving etrasimod had slightly higher odds of experiencing headache (OR = 2.07, 95% CI: 1.01-4.23), and nausea (OR = 1.84, 95% CI: 0.72-4.72). The incidences of upper respiratory tract infection (OR = 0.79, 95% CI: 0.27-2.32), nasopharyngitis (OR = 0.40, 95% CI: 0.15-1.07), and urinary tract infection (OR = 1.82, 95% CI: 0.59-5.60) were generally lower in the etrasimod groups and no treatment-related serious infections were reported. This study demonstrates that etrasimod is effective in treating moderately to severely active ulcerative colitis with a favorable benefit-risk profile at week 12. Etrasimod shows promise as a potential first-line oral therapy for individuals suffering from this disease. Additional RCTs with larger sample sizes and longer observation periods are needed to confirm the sustained efficacy of etrasimod beyond the initial phase.

Antiviral innate immune memory in alveolar macrophages following SARS-CoV-2 infection ameliorates secondary influenza A virus disease

Pathogen encounter can result in epigenetic remodeling that shapes disease caused by heterologous pathogens. Here, we examined innate immune memory in the context of commonly circulating respiratory viruses. Single-cell analyses of airway-resident immune cells in a disease-relevant murine model of SARS-CoV-2 recovery revealed epigenetic reprogramming in alveolar macrophages following infection. Post-COVID-19 human monocytes exhibited similar epigenetic signatures. In airway-resident macrophages, past SARS-CoV-2 infection increased activity of type I interferon (IFN-I)-related transcription factors and epigenetic poising of antiviral genes. Viral pattern recognition and canonical IFN-I signaling were required for the establishment of this innate immune memory and augmented secondary antiviral responses. Antiviral innate immune memory mounted by airway-resident macrophages post-SARS-CoV-2 was necessary and sufficient to ameliorate secondary disease caused by influenza A virus and curtailed hyperinflammatory dysregulation and mortality. Our findings provide insights into antiviral innate immune memory in the airway that may facilitate the development of broadly effective therapeutic strategies.

Molecular basis of CX-5461-induced DNA damage response in primary vascular smooth muscle cells

Our previous studies have shown that the novel selective RNA polymerase I inhibitor CX-5461 suppresses proliferation of vascular smooth muscle cells, mainly by inducing DNA damage response (DDR), including activations of ataxia telangiectasia mutated (ATM)/ATM and Rad3-related (ATR) and p53. Currently, there is no information about the molecular mechanism(s) underlying CX-5461-induced DDR in vascular cells, while the results obtained in cancer cells and immortalized cell lines are controversial. In this study, we examined the responses of various DDR pathways to CX-5461 treatment in primary aortic smooth muscle cells isolated from normal adult Sprague Dawley rats. We demonstrated that CX-5461-induced DDR was not associated with activations of the nucleotide excision repair, DNA mismatch repair, or the non-homologous end joining pathways, while the homologous recombination pathway was activated. However, the alkaline comet assay did not show massive DNA double strand breaks in CX-5461-treated cells. Instead, CX-5461-induced DDR appeared to be related to induction of DNA replication stress, which was not attributable to increased formation of G-quadruplex or R-loop structures, but might be explained by the increased replication-transcription conflict. CX-5461-induced DDR was not exclusively confined to rDNA within the nucleolar compartment; the extra-nucleolar DDR might represent a distinct secondary response related to the downregulated Rad51 expression in CX-5461-treated cells. In summary, we suggest that DNA replication stress may be the primary molecular event leading to downstream ATM/ATR and p53 activations in CX-5461-treated vascular smooth muscle cells. Our results provide further insights into the molecular basis of the beneficial effects of CX-5461 in proliferative vascular diseases.