Immune System Research Articles

Recommended or high daily intakes of plant stanol esters do not affect ex vivo T-cell derived cytokine production in immunologically healthy volunteers.

A well-functioning immune system requires balanced immune responses. In vitro studies have shown that plant stanols contribute to restoring the T-helper (Th)1/Th2 ratio when it is imbalanced. However, effects of plant stanols on healthy immune responses are unknown. Therefore, we studied effects of recommended (2·5 g/d) or high (9·0 g/d) plant stanol intakes on the Th1/Th2 cytokine balance in immunologically healthy subjects. In two RCTs, peripheral blood mononuclear cells (PBMCs) were isolated, cultured, and stimulated with 5 µg/ml Phytohemagglutinin-M to study ex vivo cytokine production. In the first study, twenty participants consumed margarines (2·5 g/d plant stanols) or control for three weeks. In the second study, nineteen participants consumed margarines and yogurts (9·0 g/d plant stanols) or control for four weeks. T-cell cytokine concentrations were measured in culture medium and in study 2 a standardized Th1/Th2 index was calculated. Serum lipids and non-cholesterol sterols were also measured. Compliance was confirmed by significant increases in serum total cholesterol (TC)-standardized sitostanol and campestanol levels in both studies. Changes in ex vivo cytokine production and Th1/Th2 index did not differ between intervention and control groups. In the first study, no statistically significant changes were observed in lipid and lipoprotein concentrations. In the second study, LDL cholesterol significantly decreased compared to control (-0·77 (-1·11, -0·42) mmol/l; P < 0·001). Recommended (2·5 g/d) or high (9·0 g/d) intakes of plant stanols did not alter PBMC ex vivo cytokine production in immunologically healthy subjects. This suggests that plant stanols might only affect immune function when Th1/Th2 immune responses are imbalanced.

Platelet-derived mitochondria regulate lipid metabolism in nonalcoholic steatohepatitis via extracellular vesicles

Background &amp; Aims: Immune system activation along with lipotoxicity due to excessive lipid droplet (LD) accumulation in the liver are key drivers of non-alcoholic steatohepatitis (NASH). Extracellular vesicles (EVs) released by cells that carry biological signals to contribute intercellular communication. But the roles of immune cells-derived EVs in pathogenesis of NASH are unclear. Approach &amp; Results: Platelets are abundant in blood. We explored the role of platelet-derived EVs (pEVs) in LD accumulation from 30 patients with non-alcoholic fatty liver disease of different severity as well as 20 healthy subjects, a rat model, and an in vitro cell-based assay. There was increased platelet activation, accompanied by pEVs release, in NASH patients/rat model, and palmitate-treated cells. The mitochondria in the platelets and pEVs from NASH patients/rats were increased but dysfunctional, including a reduction in fatty acid β-oxidation, inactivated ACC2, and suppressed oxidative phosphorylation system complex II/III/IV activity. These damaged mitochondria could be transferred to hepatocytes via pEVs to increase the number of lipid droplet–bound mitochondria (LDM). An increase in dysfunctional LDM in hepatocytes affects lipid metabolism, resulting in excessive LD accumulation, elevated mitochondrial ROS production, and apoptosis. Conclusions: We offer a novel molecular mechanism that connects platelets, pEVs, and excessive LD accumulation to the development of NASH. Our results suggest that NASH progression may be alleviated by specifically inhibiting the production and release of pEVs, or by targeting pEVs components and inhibiting their uptake. Additional experiments are required to confirm this potentiality.

Exploring the mediating role of immune cells in the pathogenesis of IgA nephropathy through the inflammatory axis of gut microbiota from a genomic perspective.

IgA nephropathy (IgAN) is a chronic glomerular disease characterized by the deposition of IgA antibodies in the kidney's mesangium. Its pathogenesis involves genetic, immune, and environmental factors, particularly within the mucosal immune system and gut microbiota. Immune cells play a central role in mediating these processes, which this study investigates using Mendelian Randomization (MR) to explore causal relationships among gut microbiota, inflammatory markers, blood cells, and immune cells in IgAN pathogenesis. We conducted a two-sample MR analysis using Genome-Wide Association Study (GWAS) summary data to assess the causal effects of gut microbiota, inflammatory markers, and blood cell traits on IgAN. Data sources included the FinnGen dataset for IgAN and relevant GWAS datasets for immune traits, blood cells, and inflammatory markers. Inverse variance weighting (IVW) was the primary MR method, supported by sensitivity analyses. We particularly examined the mediation effect of immune cells on these exposures' influence on IgAN. Significant associations were found between several factors and IgAN. Gut microbiota traits, such as Firmicutes E and Sporomusales, increased IgAN risk, while Citrobacter A and Herbinix reduced it. Inflammatory markers, including Interleukin-10 and Fibroblast Growth Factor 23, promoted IgAN onset. Blood cell traits like red blood cell perturbation response increased risk, while monocyte perturbation response was protective. Immune traits played a key mediating role, with Transitional %B cells reducing IgAN risk and CD28- CD25 + + CD8br %T cells increasing it. This study highlights the pivotal mediating role of immune cells in the interactions between gut microbiota, inflammatory markers, and IgAN risk. These findings identify potential biomarkers and therapeutic targets, providing new insights into the immune mechanisms underlying IgAN and opportunities for intervention.

Immune checkpoints PD1/PDL1, TIM3/GAL9 and key immune mediators landscape reveal differential expression dynamics on imatinib response in chronic myeloid leukemia.

The immune system of chronic myeloid leukemia (CML) patients is severely impaired, hampering anti-tumor responses, and maximal immune recovery occurs after achieving deep molecular responses to tyrosine kinase inhibitors. This study aimed to discern the expression patterns of NCR2, IL2, IL4, EOMES, FOXP3, GATA3, RORGT, PD1/PDL1 and TIM3/GAL9, expanding our previous dataset up to 19 key immune mediators, during the initial year on imatinib. Gene expression dynamics were evaluated in 171 peripheral blood samples from 89 CML patients, including 43 longitudinally monitored individuals, and 52 healthy donors. Univariate and unsupervised analyses confirmed diminished expression of most studied immune mediators, except for TNF, ARG1 and IL4, differentiating between baseline and 3-month samples. Most of the studied mediators normalized along treatment, with a transient increase of TNF and IL6 levels at 3-months, especially in optimal responders (BCR::ABL1 < 0.1%). Univariate and multivariate analyses showed heightened ARG1 levels and a transition from PD1/PDL1 dominance at 3 months to TIM3/GAL9 at 12 months in non-optimal responders (BCR::ABL1 ≥ 0.1%). Our longitudinal design offers a deeper exploration of immune gene expression dynamics in CML patients on imatinib, highlighting its potential implications for therapy outcomes.

Ecological drivers of CRISPR immune systems.

Microbes must constantly defend themselves against viral pathogens, and a large proportion of prokaryotes do so using the highly effective CRISPR-Cas adaptive immune system. However, many prokaryotes do not. We investigated the ecological factors behind this uneven distribution of CRISPR-Cas immune systems in natural microbial populations. We found strong patterns linking CRISPR-Cas systems to prokaryotic density within ocean environments and to prokaryotic diversity within human oral environments. Our study validates previous within-lab experimental results that suggested these factors might be important and confirms that local environment and ecological context interact to select for CRISPR immunity.

Microbial education plays a crucial role in harnessing the beneficial properties of microbiota for infectious disease protection in Crassostrea gigas.

The increase in marine diseases, particularly in economically important mollusks, is a growing concern. Among them, the Pacific oyster (Crassostrea gigas) production faces challenges from several diseases, such as the Pacific Oyster Mortality Syndrome (POMS) or vibriosis. The microbial education, which consists of exposing the host immune system to beneficial microorganisms during early life stages is a promising approach against diseases. This study explores the concept of microbial education using controlled and pathogen-free bacterial communities and assesses its protective effects against POMS and Vibrio aestuarianus infections, highlighting potential applications in oyster production. We demonstrate that it is possible to educate the oyster immune system by adding microorganisms during the larval stage. Adding culture based bacterial mixes to larvae protects only against the POMS disease while adding whole microbial communities from oyster donors protects against both POMS and vibriosis. The efficiency of immune protection depends both on oyster origin and on the composition of the bacterial mixes used for exposure. No preferential protection was observed when the oysters were stimulated with their sympatric strains. Furthermore, the added bacteria were not maintained into the oyster microbiota, but this bacterial addition induced long term changes in the microbiota composition and oyster immune gene expression. Our study reveals successful immune system education of oysters by introducing beneficial microorganisms during the larval stage. We improved the long-term resistance of oysters against critical diseases (POMS disease and Vibrio aestuarianus infections) highlighting the potential of microbial education in aquaculture.

Immunometabolic Effect of Nitric Oxide on Human Macrophages Challenged With the SARS-CoV2-Induced Cytokine Storm. A Fluxomic Approach.

The cytokine storm associated with SARS-CoV-2 infection is one of the most distinctive pathological signatures in COVID-19 patients. Macrophages respond to this pro-inflammatory challenge by reprogramming their functional and metabolic phenotypes. Interestingly, human macrophages fail to express the inducible form of the NO synthase (NOS2) in response to pro-inflammatory activation and, therefore, NO is not synthesized by these cells. The contribution of exogenously added NO, via a chemical NO-donor, on the immunometabolic changes associated with the cytokine storm is investigated. By using metabolic, transcriptomic, and functional assays the effect of NO in human macrophages is evaluated and found specific responses. Moreover, through integrative fluxomic analysis, pathways modified by NO that contribute to the expression of a particular phenotype in human macrophages are identified, which includes a decrease in mitochondrial respiration and TCA with a slight increase in the glycolytic flux. A significant ROS increase and preserved cell viability are observed in the presence of NO, which may ease the inflammatory response and host defense. Also, NO reverses the cytokine storm-induced itaconate accumulation. These changes offer additional clues to understanding the potential crosstalk between NO and the COVID-19 cytokine storm-dependent signaling pathways.

The impact of electronic cigarettes on the outcomes of total joint arthroplasty.

Cigarette smoking is known to result in poorer outcomes for patients undergoing total joint arthroplasty. Smoking tobacco cigarettes in the perioperative period is associated with higher analgesia usage, increased mortality, poorer healing, and an increased risk of medical complications. As such, many surgeons advise their patients not to smoke in the perioperative period. Electronic cigarettes are emerging as a popular alternative for usage by patients who would otherwise continue to smoke traditional cigarettes. Importantly, there has been limited investigation into the impact of electronic cigarette usage on the outcomes of total joint arthroplasty. This review investigates the potential detrimental effects caused by the usage of electronic cigarettes on the outcomes of total joint arthroplasty. A systematic review was carried out in accordance with the PRISMA Guidelines. We have drawn from studies that investigated the impact of the constituents of E-cigarette vapour on bone health, wound healing, the immune system and the direct impact of electronic cigarette usage on surgical outcomes. Electronic cigarettes release nicotine in an inconsistent manner, resulting in many negative consequences for bone health. Furthermore, they depress the immune system, impair wound healing and may result in longer hospital stays. Electronic cigarette usage should be monitored in the perioperative period to reduce the risk of complication. There is a pressing need for more comprehensive research in this area to fully understand the implications of EC usage on the outcomes of total joint arthroplasty.

Cuminaldehyde in Combination with Ciprofloxacin Shows Antibiofilm Activity against Clinical Strains of Pseudomonas aeruginosa: A Study to Explore the Underlying Mechanism

Pseudomonas aeruginosa poses a serious threat in healthcare settings. This bacterium can develop resistance to many antibiotics, rendering even last-resort treatments ineffective. Additionally, it forms protective biofilms that shield it from the immune system, making infection treatment challenging. This study investigated the susceptibility of five clinically isolated strains of the test bacteria to a combination of ciprofloxacin and cuminaldehyde. Cuminaldehyde (a natural phytochemical) and ciprofloxacin (an antibiotic) were separately found to show antimicrobial effect against test organism. However, the combination of selected compounds showed an additive effect in their microbial growth inhibitory activity. The mentioned compounds at their sub-MIC doses subjected to test whether they could show any extent of biofilm inhibition or disintegration property against the clinical strains of P. aeruginosa. The chosen concentrations of the compounds demonstrated significant antibiofilm activity against all the tested clinical strains. Additionally, it was observed that the compounds not only accumulated reactive oxygen species (ROS) but also enhanced the cell membrane permeability of the clinical strains. These findings suggest that the combination of ciprofloxacin and cuminaldehyde could explore new directions in fighting P. aeruginosa-linked infections.

The Role of T Cells in the Pathogenesis of Narcolepsy Type 1: A Narrative Review

Narcolepsy type 1 (NT1) is an uncommon, persistent sleep disorder distinguished by significant daytime sleepiness, episodes of cataplexy, and irregularities in rapid eye movement sleep. The etiology of NT1 is linked to the destruction of hypothalamic neurons responsible for the synthesis of the wake-promoting neuropeptide known as hypothalamic orexin. The pathophysiological mechanisms underlying NT1 remain inadequately elucidated; however, a model that incorporates the interplay of genetic predisposition, environmental influences, immune system factors, and a deficiency in hypocretin (HCRT) provides a framework for elucidating the pathogenesis of NT1. The prevalence of NT1 has been observed to rise following influenza A (H1N1) pdm09 and the administration of the Pandemrix influenza vaccine. The strong association between narcolepsy and the HLA-DQB1*06:02 allele strongly indicates an autoimmune etiology for this condition. Increasing evidence suggests that T cells play a critical role in this autoimmune-mediated HCRT neuronal loss. Studies have identified specific T cell subsets, including CD4+ and CD8+ T cells, that target HCRT neurons, contributing to their destruction. Clarifying the pathogenesis of NT1 driven by autoimmune T cells is crucial for the development of effective therapeutic interventions for this disorder. This review examines the risk factors associated with the pathogenesis of NT1, explores the role of T cells within the immune system in the progression of NT1, and evaluates immune-mediated animal models alongside prospective immunotherapeutic strategies.

The R1441C-Lrrk2 mutation induces myeloid immune cell exhaustion in an age- and sex-dependent manner in mice

Age is the greatest risk factor for many neurodegenerative diseases, yet immune system aging, a contributor to neurodegeneration, is understudied. Genetic variation in the LRRK2 gene affects risk for both familial and sporadic Parkinson’s disease (PD). The leucine-rich repeat kinase 2 (LRRK2) protein is implicated in peripheral immune cell signaling, but the effects of an aging immune system on LRRK2 function remain unclear. We analyzed peritoneal macrophages from R1441C-Lrrk2 knock-in mice and observed a biphasic, age-dependent effect of the R1441C-Lrrk2 mutation on peritoneal macrophage function. We report increases in antigen presentation, anti-inflammatory cytokine production, lysosomal activity, and pathogen uptake in peritoneal macrophages from young (2- to 3-month-old) female R1441C-Lrrk2 mice. Conversely, macrophages from aged (18- to 21-month-old) female R1441C-Lrrk2 mice exhibited decreased antigen presentation after inflammatory insult, decreased lysosomal function, and pathogen uptake, with a concomitant increase in DNA fragmentation in the presence of pathogens. This immune cell exhaustion phenotype was not observed in male R1441C-Lrrk2 mice and was driven by increased LRRK2 protein kinase activity. This phenotype was also observed in human peripheral myeloid cells, with monocyte-derived macrophages from patients with PD who had either the R1441C- or Y1699C-LRRK2 mutation exhibiting decreased pathogen uptake and increased PDL1 expression, consistent with immune cell exhaustion. Our findings that LRRK2 mutations conferred an immunological advantage at a young age but could predispose the carrier to age-acquired immune cell exhaustion have implications for the therapeutic development of LRRK2 inhibitors.

A Pro-Angiogenic Immunoprotective Membrane for Cell Therapies.

Immunoisolation strategies that rely on porous membranes play an important role in cell transplantation therapies to protect cells from the host's immune system. These membranes must possess immunoprotective properties while facilitating the transport of nutrients and cell products to maintain the functional integrity of encapsulated cells. An easy and scalable process is described to fabricate a dual function porous polymeric membrane that shields cells against immune cell attack and promotes vascularization to address the nutritional and oxygen requirements of transplanted cells. The fabrication process results in a membrane cross-section with a gradient of nanopores to micropores that support cell immunoisolation and interfacial vascularization requirements, respectively. The membranes demonstrate excellent cell compatibility and effectively prevent T cell transmigration without compromising glucose diffusion and oxygen permeability. In a murine subcutaneous implantation model, membranes are stable for 60 days and exhibit significantly reduced fibrous capsules, with enhanced vascularization near the membrane. These porous polymeric membranes can potentially be used as pro-angiogenic immunoprotective membranes for cell transplantation applications where maximizing cell viability and function is of critical importance.

Immunoproteomics: A Review of Techniques, Applications, and Advancements.

Immunoproteomics is the branch of proteomics with an emphasis on the study of functional peptides and proteins related to the immune system. Combining proteomics techniques with immunological research aims to uncover the complex interactions of proteins involved in immune responses. This review discusses the methods, applications, and recent advancements in immunoproteomics, highlighting its critical role in understanding immune responses, discovering biomarkers, and developing vaccines and therapeutics. This study offers a comprehensive exploration of the methodologies, applications, and advancements within immunoproteomics. Techniques such as mass spectrometry, antibody-based assays, and computational analysis are pivotal in unraveling the complexities of the immune system at the protein level. Immunoproteomics finds diverse applications in biomarker discovery, vaccine development, autoimmune disease research, infectious disease diagnostics, and cancer immunotherapy. Challenges, including data integration, sample heterogeneity, and biomarker validation, persist, necessitating innovative approaches and interdisciplinary collaborations. In the future, immunoproteomics will likely play a major role in expanding our knowledge of immune-related diseases and accelerating the creation of targeted and precise immunotherapies.

Evolution of g-type lysozymes in metazoa: insights into immunity and digestive adaptations

Exploring the evolutionary dynamics of lysozymes is critical for advancing our knowledge of adaptations in immune and digestive systems. Here, we characterize the distribution of a unique class of lysozymes known as g-type, which hydrolyze key components of bacterial cell walls. Notably, ctenophores, and choanoflagellates (the sister group of Metazoa), lack g-type lysozymes. We reveal a mosaic distribution of these genes, particularly within lophotrochozoans/spiralians, suggesting the horizontal gene transfer events from predatory myxobacteria played a role in their acquisition, enabling specialized dietary and defensive adaptations. We further identify two major groups of g-type lysozymes based on their widespread distribution in gastropods. Despite their sequence diversity, these lysozymes maintain conserved structural integrity that is crucial for enzymatic activity, underscoring independent evolutionary pathways where g-type lysozymes have developed functionalities typically associated with different lysozyme types in other species. Specifically, using Aplysia californica as a reference species, we identified three distinct g-type lysozyme genes: two are expressed in organs linked to both feeding and defense, and the third exhibits broader distribution, likely associated with immune functions. These findings advance our understanding of the evolutionary dynamics shaping the recruitment and mosaic functional diversification of these enzymes across metazoans, offering new insights into ecological physiology and physiological evolution as emerging fields.

VBNC Cronobacter sakazakii survives in macrophages by resisting oxidative stress and evading recognition by macrophages.

Survival in host macrophages is an effective strategy for pathogenic bacterial transmission and pathogenesis. Our previous study found that viable but non-culturable (VBNC) Cronobacter Sakazakii (C. sakazakii) can survive in macrophages, but its survival mechanism is not clear. In this study, we investigated the possible mechanisms of VBNC C. sakazakii survival in macrophages in terms of environmental tolerance within macrophages and evasion of macrophages recognition. The results revealed that VBNC C. sakazakii survived under oxidative conditions at a higher rate than the culturable C. sakazakii. Moreover, the stringent response gene (relA and spoT) and the antioxidant-related genes (sodA, katG, and trxA) were up-regulated, indicating that VBNC C. sakazakii may regulate antioxidation through stringent response. On the other hand, compared with culturable C. sakazakii, VBNC C. sakazakii caused reduced response (Toll-like receptor 4) in macrophages, which was attributed to the suppression of biosynthesis of the lipopolysaccharides (LPS). Furthermore, we found that ellagic acid can reduce the survival rate of bacteria in macrophages by improving the immune TLR4 recognition ability of macrophages. In conclusion, VBNC C. sakazakii may survive in macrophages by regulating oxidative tolerance through stringent response and altering LPS synthesis to evade TLR4 recognition by macrophages, which suggests the pathogenic risk of VBNC C. sakazakii.

Role of the basic leucine zipper transcription factor BATF2 in modulating immune responses and inflammation in health and disease.

Basic leucine zipper transcription factor ATF-like 2 (BATF2) is a transcription factor that is known to exhibit tumor-suppressive activity in cancer cells. Within recent years, however, BATF2 has also emerged as an important transcriptional regulator of the immune system. Through its immunomodulatory function, BATF2 has been implicated in a variety of (patho)physiological processes, including host defense against infection, anti-tumor immunity, and maintenance of tissue inflammatory homeostasis. Below, we discuss recent literature that has provided insight into the role of BATF2 as a transcriptional regulator of immune responses in health and disease, including the cell types that express BATF2, the different diseases in which the immunomodulatory effects of BATF2 have been shown to play a role, and the molecular mechanisms through which BATF2 is thought to exert those effects. In doing so, we highlight that the immunological effects of BATF2 are highly context-dependent, and we point out overlap between the mechanisms of action of BATF2 in infectious disease and non-infectious disease. We also discuss areas of interest for future research, the clinical relevance of better understanding BATF2 function, and potential strategies for therapeutic modulation of BATF2.

A widespread phage-encoded kinase enables evasion of multiple host antiphage defence systems.

DNA degradation (Dnd) is a widespread bacterial antiphage defence system that relies on DNA phosphorothioate (PT) modification for self/non-self discrimination and subsequent degradation of unmodified DNA. Phages employ counterstrategies to evade host immunity, but anti-Dnd immunity has not been characterized. Here we report an immune evasion protein encoded by the Salmonella phage JSS1 that contributes to subverting Dnd and other defence systems. Using quantitative proteomic and phosphoproteomic analyses, we show that the protein JSS1_004 employs N-terminal Ser/Thr/Tyr protein kinase activity to catalyse the multisite phosphorylation of host DndFGH. Notably, JSS1_004 also phosphorylates other bacterial immune systems to varying degrees, including CRISPR‒Cas, QatABCD, SIR2+HerA and DUF4297+HerA. Given that JSS1_004 and its homologues are widespread in phylogenetically diverse phages, we suggest that this strategy constitutes a family of immune evasion proteins that increases the chances of phage proliferation even when a host deploys multiple defence systems.

Construction and validation of a prognostic signature based on microvascular invasion and immune-related genes in hepatocellular carcinoma.

Microvascular invasion (MVI) is an independent risk factor of poor prognosis in hepatocellular carcinoma (HCC) and can be used to guide the diagnosis and treatment of HCC. The immune system serves as an integral role in the incidence and progression of HCC. However, the molecular biology correlation between MVI and tumor immunity and the value of combining the two parameters to predict patient prognosis and HCC response to treatment remain to be evaluated. In this study, we used univariate Cox regression analysis and least absolute shrinkage and selection operator (LASSO) Cox analysis to establish the MVI and immune-related gene index (MIRGPI) including eight genes. We demonstrated that the MIRGPI was an independent risk factor in predicting the prognosis of HCC. Subsequently, our research established a nomogram model combining pathologic characteristics and verified its good clinical application value. In addition, our study found that the TP53 gene had a higher mutation frequency and a lower degree of immune infiltration in the high-risk group. The low-risk group had higher sensitivity to immunotherapy, sorafenib, and TACE treatment, and the high-risk group had higher sensitivity to common chemotherapeutic agents. Finally, SEMA3C was found to facilitate the proliferation, migration and invasive ability of HCC by in vitro and in vivo experiments, and its mechanism may be associated with the activation of the NF-Κb/EMT signaling pathway. In summary, the MIRGPI signature we developed is a reliable marker for the prediction of prognosis and treatment response, and is important for the prognostic assessment and individualized treatment of HCC.

Agrobacterium-Mediated Transformation and Targeted Mutagenesis Using SpCas12f in Rice.

Clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (Cas) (CRISPR-Cas) is an adaptive prokaryote immune system against foreign DNA/RNA that is now applied widely to genome editing. A miniature Cas, CRISPR-Cas12f, is one-half to one-third the size of the CRISPR-Cas9 that is commonly used in genome editing experiments in many organisms, including higher plants. The compactness of CRISPR-Cas12f is expected to be advantageous in terms of vector construction and transformation frequency. Moreover, CRISPR-Cas12f can be useful for virus vector-mediated genome editing because the size of the transgene is the major restriction in the use of virus vectors. Here, we describe our protocol for targeted mutagenesis using Cas12f derived from Syntrophomonas palmitatica (SpCas12f) via Agrobacterium-mediated transformation in rice. We also summarize some approaches to improve the frequency of targeted mutagenesis using SpCas12f.

Tetracycline and Oxacillin Act Synergistically on Biofilms and Display Increased Efficacy In Vivo Against Staphylococcus aureus.

Oxacillin (bactericidal) and tetracycline (bacteriostatic) are clinically relevant antibiotics that are routinely prescribed to treat Staphylococcus aureus infections but not conventionally used in combination. There is an urgent need for treatment regimens that can act upon biofilms during infection, associated with chronic infections on indwelling devices, as well as acute planktonic (systemic) infection. Here we show that in an in vitro model oxacillin and tetracycline act synergistically against S. aureus UAMS-1 biofilms, reducing the concentration of both antibiotics necessary to eradicatean established biofilm. Using an in vivo zebrafish larval infection model with S. aureus NewHG, they display improved bacterial clearance compared to each drug alone and can counteract a loss of host phagocytes, an important innate defence against S. aureus. In these cases, the bacteriostatic nature of tetracycline enhances rather than dampens the bactericidal action of oxacillin, although an exact mechanism remains to be elucidated. We suggest a dual therapy could be of clinical use against biofilm-forming S. aureus and has a potential use in patients with a compromised immune system.