Toll-like receptor 9 signaling is associated with immune responses to Trypanosoma brucei infection.

Trypanosoma brucei, a causative agent of human and animal trypanosomiasis, regularly switches its major surface antigen to avoid elimination by the immune system. Toll-like receptor 9 (TLR9) is a key modulator for resistance to host-infective trypanosomes; however, the underlying molecular mechanism remains indistinct. Thus, we first approached the issue using Tlr9-mutant mice that render them non-responsive to TLR9 agonists. After infection, T cells in the spleens of Tlr9-mutant mice were analyzed by flow cytometry and a reduction in CD8+, CD4+ T, and NKT cells was observed in Tlr9-mutant mice compared to WT mice. We further found that the responses of inflammatory cytokines in the sera were reduced in Tlr9-mutant mice after T. brucei infection. The underlying molecular mechanism was that T. b. brucei DNA activated TLR9, which consequently upregulated the expression of p38 and ERK/MAPK, resulting in host resistance to trypanosome infection. In conclusion, these findings provide novel insights into the TLR9-mediated host responses to trypanosome infection.

Plasmodium falciparum selectively degrades α-spectrin of infected erythrocytes after invasion.

Remodeling the erythrocyte membrane and skeleton by the malarial parasite Plasmodium falciparum is closely associated with intraerythrocytic development. However, the mechanisms underlying this association remain unclear. In this study, we present evidence that erythrocytic α-spectrin, but not ß-spectrin, was dynamically ubiquitinated and progressively degraded during the intraerythrocytic development of P. falciparum, from the ring to the schizont stage. We further observed an upregulated expression of P. falciparum phosphatidylinositol 3-kinase (PfPI3K) in the infected red blood cells during the intraerythrocytic development of the parasite. The data indicated that PfPI3K phosphorylated and activated erythrocytic ubiquitin-protein ligase, leading to increased α-spectrin ubiquitination and degradation during P. falciparum development. We further revealed that inhibition of the activity of PfPI3K impaired P. falciparum development in vitro and Plasmodium berghei infectivity in mice. These findings collectively unveil an important mechanism of PfPI3K-ubiquitin-mediated degradation of α-spectrin during the intraerythrocytic development of Plasmodium species. Proteins in the PfPI3K regulatory pathway are novel targets for effective treatment of severe malaria. IMPORTANCE: Plasmodium falciparum is the causative agent of severe malaria that causes millions of deaths globally. The parasite invades human red blood cells and induces a cascade of alterations in erythrocytes for development and proliferation. Remodeling the host erythrocytic cytoskeleton is a necessary process during parasitization, but its regulatory mechanisms remain to be elucidated. In this study, we observed that erythrocytic α-spectrin is selectively degraded after P. falciparum invasion, while ß-spectrin remained intact. We found that the α-spectrin chain was profoundly ubiquitinated by E3 ubiquitin ligase and degraded by the 26S proteasome. E3 ubiquitin ligase activity was regulated by P. falciparum phosphatidylinositol 3-kinase (PfPI3K) signaling. Additionally, blocking the PfPI3K-ubiquitin-proteasome pathway in P. falciparum-infected red blood cells reduced parasite proliferation and infectivity. This study deepens our understanding of the regulatory mechanisms of host and malarial parasite interactions and paves the way for the exploration of novel antimalarial drugs.

Comparative analysis of multi-angle structural alterations and cold-water solubility of kudzu starch modifications using different methods.

Kudzu, a plant known for its medicinal value and health benefits, is typically consumed in the form of starch. However, the use of native kudzu starch is limited by its high pasting temperature and low solubility, leading to a poor consumer experience. In this study, kudzu starch was treated using six modification techniques: ball milling, extrusion puffing, alcoholic-alkaline, urea-alkaline, pullulanase, and extrusion puffing-pullulanase. The results of the Fourier transform infrared spectrum showed that the intensity ratio of 1047/1022 cm-1 for the modified starches (1.02-1.21) was lower than that of the native kudzu starch (1.22). The relative crystallinity of modified kudzu starch significantly decreased, especially after ball milling, extrusion puffing, and alcoholic-alkaline treatment. Furthermore, scanning electron microscopy and confocal laser scanning microscopy revealed significant changes in the granular structures of the modified starches. After modification, the pasting temperature of kudzu starch decreased (except for the urea-alkaline treatment), and the apparent viscosity of kudzu starch decreased from 517.95 Pa·s to 0.47 Pa·s. The cold-water solubility of extrusion-puffing and extrusion puffing-pullulanase modified kudzu starch was >70 %, which was significantly higher than that of the native starch (0.11 %). These findings establish a theoretical basis for the potential development of instant kudzu powder.

Toxoplasma sortilin interacts with secretory proteins and it is critical for parasite proliferation.

BACKGROUND: The human sortilin protein is an important drug target and detection marker for cancer research. The sortilin from Toxoplasma gondii transports proteins associated with the apical organelles of the parasite. In this study, we aimed to determine the intracellular localization and structural domains of T. gondii sortilin, which may mediate protein transportation. Approaches to the functional inhibition of sortilin to establish novel treatments for T. gondii infections were explored. METHODS: A gene encoding the sortilin protein was identified in the T. gondii genome. Immunoprecipitation and mass spectrometry were performed to identify the protein species transported by T. gondii sortilin. The interaction of each structural domain of sortilin with the transported proteins was investigated using bio-layer interferometry. The binding regions of the transported proteins in sortilin were identified. The effect of the sortilin inhibitor AF38469 on the infectivity of T. gondii was investigated. The binding site of AF38469 on sortilin was determined. RESULTS: The subdomains Vps10, sortilin-C, and sortilin-M of the sortilin were identified as the binding regions for intracellular transportation of the target proteins. The sortilin inhibitor AF38469 bound to the Vps10 structural domain of T. gondii sortilin, which inhibited parasite invasion, replication, and intracellular growth in vitro and was therapeutic in mice infected with T. gondii. CONCLUSION: The Vps10, sortilin-C, and sortilin-M subdomains of T. gondii sortilin were identified as functional regions for intracellular protein transport. The binding region for the sortilin inhibitor AF38469 was also identified as the Vps10 subdomain. This study establishes sortilin as a promising drug target against T. gondii and provides a valuable reference for the development of anti-T. gondii drug-target studies.

Boosting Mouse Defense against Lethal Toxoplasma gondii Infection with Full-Length and Soluble SAG1 Recombinant Protein.

Toxoplasmosis is a major worldwide protozoan zoonosis. The surface antigen 1 (SAG1) of Toxoplasma gondii (T. gondii) has always been recognized as an ideal vaccine candidate antigen. However, the intact and soluble SAG1 protein is usually difficult to acquire in vitro, which is unfavorable for employing the recombinant protein as a vaccine candidate antigen. In the present study, we obtained the full-length SAG1 recombinant protein in soluble form by Escherichia coli Transetta (DE3) cells under optimized expression conditions. The immunogenicity and protective ability of this recombinant protein against T. gondii acute infection were evaluated in a mouse model. Monitoring changes in serum antibody levels and types, the presence of cytokines, and the rate of lymphocyte proliferation in vaccinated mice were used to assess humoral and cellular immune responses. Additional assessments were performed to determine the protective potency of the recombinant protein in combating T. gondii RH tachyzoites. It was found that the titers of both IgG2a and IgG2b were considerably greater in the immunized mice compared to the titers of IgG1 and IgG3. The levels of Th1-type cytokines (IFN-γ, IL-12p70, IL-2, and TNF-α) and Th2-type cytokines (IL-10) significantly increased when splenocytes from immunological group mice were treated with T. gondii lysate antigen. Compared to the control group, a recombinant protein substantially increased the longevity of infected mice, with an average death time prolonged by 14.50 ± 0.34 days (p < 0.0001). These findings suggest that the full-length and soluble SAG1 recombinant protein produced potent immune responses in mice and could be a preferred subunit vaccine candidate for T. gondii, offering a feasible option for vaccination against acute toxoplasmosis.

High-Safety Lithium-Ion Batteries with Silicon-Based Anodes Enabled by Electrolyte Design.

High-energy-density lithium-ion batteries (LIBs) with high safety have long been pursued for extending the cruise range of electric vehicles. Owing to the high gravimetric capacity, silicon is a promising alternative to the convention graphite anode for high-energy LIBs. However, it suffers from intrinsic poor interfacial stability with liquid electrolytes, inevitably increasing the risk of thermal runaway and posing serious safety challenges. In this review, we will focus on mitigating thermal runaway of silicon anodes-based LIBs from the perspective of electrolyte design. First, the thermal runaway mechanism of LIBs is briefly introduced, while the specific thermal failure reactions associated with silicon anodes and electrolytes are discussed in detail. We then summarize the safety countermeasures (e. g., thermally stable solid electrolyte interphase, nonflammable electrolytes, highly stable lithium salts, mitigating electrode crosstalk, and solid-state electrolytes) enabled by customized electrolyte design to address these triggers of thermal runaway. Finally, the remaining unanswered questions regarding the thermal runaway mechanism are presented, and future directions to achieve intrinsically safe electrolytes for silicon-based anodes are prospected. This review is expected to provide insightful knowledge for improving the safety of LIBs with silicon-based anodes.

A heparin-binding protein of Plasmodium berghei is associated with merozoite invasion of erythrocytes.

BACKGROUND: Malaria caused by Plasmodium species is a prominent public health concern worldwide, and the infection of a malarial parasite is transmitted to humans through the saliva of female Anopheles mosquitoes. Plasmodium invasion is a rapid and complex process. A critical step in the blood-stage infection of malarial parasites is the adhesion of merozoites to red blood cells (RBCs), which involves interactions between parasite ligands and receptors. The present study aimed to investigate a previously uncharacterized protein, PbMAP1 (encoded by PBANKA_1425900), which facilitates Plasmodium berghei ANKA (PbANKA) merozoite attachment and invasion via the heparan sulfate receptor. METHODS: PbMAP1 protein expression was investigated at the asexual blood stage, and its specific binding activity to both heparan sulfate and RBCs was analyzed using western blotting, immunofluorescence, and flow cytometry. Furthermore, a PbMAP1-knockout parasitic strain was established using the double-crossover method to investigate its pathogenicity in mice. RESULTS: The PbMAP1 protein, primarily localized to the P. berghei membrane at the merozoite stage, is involved in binding to heparan sulfate-like receptor on RBC surface of during merozoite invasion. Furthermore, mice immunized with the PbMAP1 protein or passively immunized with sera from PbMAP1-immunized mice exhibited increased immunity against lethal challenge. The PbMAP1-knockout parasite exhibited reduced pathogenicity. CONCLUSIONS: PbMAP1 is involved in the binding of P. berghei to heparan sulfate-like receptors on RBC surface during merozoite invasion.

A Systematic Meta-Analysis of Global Sarcocystis Infection in Sheep and Goats.

Sarcocystosis is an intracellular parasitic disease caused by Sarcocystis spp. that has a worldwide prevalence. Symptoms of the disease include diarrhea and muscle pain. The disease poses a threat to the health of animals. The aim of this review is to investigate the global prevalence of Sarcocystis infection in sheep and goats during 2013-2022. We searched five databases: Web of Science, Science Direct, PubMed, Scopus, and Google Scholar. A total of 36 articles containing 44 datasets met the criteria and were included in the study. The total infection rates of Sarcocystis in sheep and goats were 66.3% (95% CI, 51.79-79.38%) and 52.1% (95% CI, 29.45-74.23%), respectively. It was found that Sarcocystis species tend to have a host species preference. Coinfection of S. tenella and S. arieticanis often occurred in sheep, and goats were frequently infected with S. capracanis. Age and sex were identified as risk factors for Sarcocystis infection in sheep and goats. The infection rates of female and male animals were significantly different, with females having a higher infection rate. Age-adjusted analysis showed that infection rates in animals older than one year were higher than in animals younger than one year. This study unveiled the global distribution of Sarcocystis and sheds light on its transmission in sheep and goats.

Co-Immunization with DNA Vaccines Expressing SABP1 and SAG1 Proteins Effectively Enhanced Mice Resistance to Toxoplasma gondii Acute Infection.

Toxoplasma gondii (T. gondii) has many intermediate hosts, obligately invades nucleated cells, and seriously threatens human and animal health due to a lack of effective drugs and vaccines. Sialic acid-binding protein 1 (SABP1) is a novel invasion-related protein that, like surface antigen 1 (SAG1), is found on the plasma membrane of T. gondii. To investigate the immunogenicity and protective efficacy of DNA vaccines expressing SABP1 and SAG1 proteins against T. gondii acute infection, the recombinant plasmids pVAX1-SABP1 and pVAX1-SAG1 were produced and administered intramuscularly in Balb/c mice. Serum antibody levels and subtypes, lymphocyte proliferation, and cytokines were used to assess immunized mice's humoral and cellular immune responses. Furthermore, the ability of DNA vaccines to protect mice against T. gondii RH tachyzoites was tested. Immunized mice exhibited substantially higher IgG levels, with IgG2a titers higher than IgG1. When the immune group mice's splenocytes were stimulated with T. gondii lysate antigen, Th1-type cytokines (IL-12p70, IFN-γ, and IL-2) and Th2-type cytokine (IL-4) increased significantly. The combined DNA vaccine significantly increased the immunized mouse survival compared to the control group, with an average death time extended by 4.33 ± 0.6 days (p < 0.0001). These findings show that DNA vaccines based on the SABP1 and SAG1 genes induced robust humoral and cellular immunity in mice, effectively protecting against acute toxoplasmosis and potentially serving as a viable option for vaccination to prevent T. gondii infection.

VCAM-1+ hUC-MSCs Exert Considerable Neuroprotection Against Cerebral Infarction in Rats by Suppression of NLRP3-Induced Pyroptosis.

Mesenchymal stem/stromal cells (MSCs) are spindle-like heterogeneous cell populations with advantageous bidirectional immunomodulatory and hematopoietic support effects. Vascular cellular adhesion molecule-1 (VCAM-1)+ MSCs have been reported to exhibit immunoregulatory and proangiogenic capacities. Here, we studied the effects of VCAM-1+ human umbilical cord (hUC)-MSCs on neuroprotection against cerebral infarction. Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO), and VCAM-1- and VCAM-1+ hUC-MSCs were intravenously injected into the rat 4 h post-MCAO surgery. Thereafter, modified neurological severity scores (mNSS) were determined, and the Morris water maze test, 2,3,5-triphenyltetrazolium chloride (TTC), hematoxylin and eosin (H&E), Nissl, TUNEL staining, and qRT-PCR were conducted. Following induction of oxygen-glucose deprivation/reoxygenation (OGD/R), SH-SY5Y cells were co-cultured with VCAM-1- and VCAM-1+ hUC-MSCs. CCK-8, flow cytometry, ELISA, and western blot analyses were performed in vitro. Compared with VCAM-1- hUC-MSCs, administration of VCAM-1+ hUC-MSCs revealed improved therapeutic efficacy against cerebral infarction in rats, as confirmed by lower mNSS scores and infarct volumes, as well as improved learning and memory capacities. In addition, VCAM-1+ hUC-MSCs exhibited improved efficacy against neurological defects in rats with cerebral infarction, accompanied by inhibition of the NLRP3-mediated inflammatory response. VCAM-1+ hUC-MSC co-culture improved the viability and diminished NLRP3-mediated inflammatory response in OGD/R-treated SH-SY5Y cells. Moreover, NLRP3 overexpression in SH-SY5Y cells prevented the beneficial effects of VCAM-1+ hUC-MSC co-culture. Overall, our findings demonstrated the relevance of VCAM-1+ hUC-MSC-based cytotherapy for preclinical neuroprotection against cerebral infarction.

A Metabolomic and Transcriptomic Study Revealed the Mechanisms of Lumefantrine Inhibition of Toxoplasma gondii.

Toxoplasma gondii is an obligate protozoon that can infect all warm-blooded animals including humans. T. gondii afflicts one-third of the human population and is a detriment to the health of livestock and wildlife. Thus far, traditional drugs such as pyrimethamine and sulfadiazine used to treat T. gondii infection are inadequate as therapeutics due to relapse, long treatment period, and low efficacy in parasite clearance. Novel, efficacious drugs have not been available. Lumefantrine, as an antimalarial, is effective in killing T. gondii but has no known mechanism of action. We combined metabolomics with transcriptomics to investigate how lumefantrine inhibits T. gondii growth. We identified significant alternations in transcripts and metabolites and their associated functional pathways that are attributed to lumefantrine treatment. RH tachyzoites were used to infect Vero cells for three hours and subsequently treated with 900 ng/mL lumefantrine. Twenty-four hours post-drug treatment, we observed significant changes in transcripts associated with five DNA replication and repair pathways. Metabolomic data acquired through liquid chromatography-tandem mass spectrometry (LC-MS) showed that lumefantrine mainly affected sugar and amino acid metabolism, especially galactose and arginine. To investigate whether lumefantrine damages T. gondii DNA, we conducted a terminal transferase assay (TUNEL). TUNEL results showed that lumefantrine significantly induced apoptosis in a dose-dependent manner. Taken together, lumefantrine effectively inhibited T. gondii growth by damaging DNA, interfering with DNA replication and repair, and altering energy and amino acid metabolisms.

Dihydroartemisinin imposes positive and negative regulation on Treg and plasma cells via direct interaction and activation of c-Fos.

Dihydroartemisinin (DHA), a potent antimalarial drug, also exhibits distinct property in modulation on Treg and B cells, which has been recognized for decades, but the underlying mechanisms remain understood. Herein we revealed that DHA could promote Treg proliferation, meanwhile, suppress B cell expansion in germinal centers, and consequently decrease the number of circulating plasma cells and the content of serum immunoglobulins. Further, DHA-activated Treg significantly mitigated lipopolysaccharide-induced and malaria-associated inflammation. All these scenarios were attributed to the upregulation of c-Fos expression by DHA and enhancement of its interaction with target genes in both Treg and circulating plasma cells with bilateral cell fates. In Treg, the c-Fos-DHA complex upregulated cell proliferation-associated genes and promoted cell expansion; whereas in plasma cells, it upregulated the apoptosis-related genes resulting in decreased circulating plasma cells. Thus, the bilateral immunoregulatory mechanism of DHA was elucidated and its application in the treatment of autoimmune diseases is further justified.

Establishment of a method for detecting Trichinella spiralis in ovine muscle tissues using real-time fluorescence quantitative PCR.

Trichinellosis is caused by Trichinella spiralis, a meat-borne zoonotic disease transmitted to humans through the consumption of infected undercooked or raw meat. Surveillance using safe and precise diagnostic tools to diagnose T. spiralis in sheep is needed to assess the incidence and probability of transmission from sheep to humans. In this study, we developed a real-time PCR assay to detect T. spiralis DNA in ovine muscle samples that can be used as an alternative surveillance tool to ensure food safety using newly designed primers. The assay is specific for the Scfld4 gene of Trichinella (T1) and enables the detection of larvae in ovine muscle tissue samples with high sensitivity and specificity. Trichuris ovis, Oesophagostomum dentatum, Haemonchus contortus, and Bunostomum trigonocephalum showed no nonspecific amplification. The assay could detect Trichinella DNA concentrations as low as 0.0026 ng/µL, equivalent to 0.0064 larvae, indicating a high sensitivity for T. spiralis detection. We used this real-time PCR to detect 73 ovine muscle samples from an ovine abattoir, and five samples tested positive via real-time PCR but negative via microscopy. This assay may provide a more specific and sensitive method for rapidly detecting Trichinella larvae in ovine muscle tissues.

Graphene quantum dots induce cascadic apoptosis via interaction with proteins associated with anti-oxidation after endocytosis by Trypanosoma brucei.

Trypanosoma brucei, the pathogen causing African sleeping sickness (trypanosomiasis) in humans, causes debilitating diseases in many regions of the world, but mainly in African countries with tropical and subtropical climates. Enormous efforts have been devoted to controlling trypanosomiasis, including expanding vector control programs, searching for novel anti-trypanosomial agents, and developing vaccines, but with limited success. In this study, we systematically investigated the effect of graphene quantum dots (GQDs) on trypanosomal parasites and their underlying mechanisms. Ultrasmall-sized GQDs can be efficiently endocytosed by T. brucei and with no toxicity to mammalian-derived cells, triggering a cascade of apoptotic reactions, including mitochondrial disorder, intracellular reactive oxygen species (ROS) elevation, Ca2+ accumulation, DNA fragmentation, adenosine triphosphate (ATP) synthesis impairment, and cell cycle arrest. All of these were caused by the direct interaction between GQDs and the proteins associated with cell apoptosis and anti-oxidation responses, such as trypanothione reductase (TryR), a key protein in anti-oxidation. GQDs specifically inhibited the enzymatic activity of TryR, leading to a reduction in the antioxidant capacity and, ultimately, parasite apoptotic death. These data, for the first time, provide a basis for the exploration of GQDs in the development of anti-trypanosomials.

Impact prediction of translocation of the mitochondrial outer membrane 70 as biomarker in Alzheimer's disease.

Mitochondrial dysfunction plays a key role in the pathogenesis of Alzheimer's disease (AD). The translocase of the outer membrane (TOM) complex controls the input of mitochondrial precursor proteins to maintain mitochondrial function under pathophysiological conditions. However, its role in AD development remains unclear. TOM70 is an important translocase present in the TOM complex. In the current study, we found that TOM70 levels were reduced in the peripheral blood and hippocampus of the APP/PS1 mice. In addition, we examined the whole-blood mRNA levels of TOM70 in patients with AD, dementia with Lewy bodies (DLB), and post-stroke dementia (PSD). Our study revealed that the mRNA level of TOM70 was decreased in the blood samples of patients with AD, which was also correlated with the progression of clinical stages. Therefore, we proposed that the expression of TOM70 could be a promising biomarker for AD diagnosis and monitoring of disease progression.

Protein Lactylation and Metabolic Regulation of the Zoonotic Parasite Toxoplasma gondii.

The biology of Toxoplasma gondii, the causative pathogen of one of the most widespread parasitic diseases (toxoplasmosis), remains poorly understood. Lactate, which is derived glucose metabolism, is not only an energy source in a variety of organisms, including T. gondii, but also a regulatory molecule that participates in gene activation and protein function. Lysine lactylation (Kla) is a type of posttranslational modification (PTM) that has been recently associated with chromatin remodeling; however, Kla of histone and non-histone proteins has not yet been studied in T. gondii. To examine the prevalence and function of lactylation in T. gondii parasites, we mapped thelactylome of proliferating tachyzoite cells and identified 1964 lactylation sites on 955 proteins in the T. gondii RH strain. Lactylated proteins are distributed in multiple subcellular compartments and are closely related to a wide variety of biological processes, including mRNA splicing, glycolysis, aminoacyl-tRNA biosynthesis, RNA transport, and many signaling pathways. We also performed a chromatin immunoprecipitation sequencing (ChIP-seq) analysis using a lactylation-specific antibody and found that the histones H4K12la and H3K14la were enriched in the promoter and exon regions of T. gondii associated with microtubule-based movement and cell invasion. We further confirmed the delactylase activity of histone deacetylases TgHDACs 2, 3, and 4, and found that treatment with anti-histone acetyltransferase (TgMYST-A) antibodies profoundly reduced protein lactylation in T. gondii. This study offers the first dataset of the global lactylation proteome and provides a basis for further dissecting the functional biology of T. gondii.

Dihydroartemisinin regulates immune cell heterogeneity by triggering a cascade reaction of CDK and MAPK phosphorylation.

Artemisinin (ART) and dihydroartemisinin (DHA), apart from their profound anti-malaria effect, can also beneficially modulate the host immune system; however, the underlying molecular mechanisms remain unclear. Here, we report that DHA selectively induced T-cell activation, with an increased proportion of Ki67+CD4+ T cells, CD25+CD4+ T cells, interferon (IFN)-γ-producing CD8+ T cells, Brdu+ CD8+ T cells and neutrophils, which was found to enhance cellular immunity to experimental malaria and overcome immunosuppression in mice. We further revealed that DHA upregulated the expression of cell proliferation-associated proteins by promoting the phosphorylation of mitogen-activated protein kinase (MAPK), cyclin-dependent kinases (CDKs), and activator protein 1 in the spleen. This study is the first to provide robust evidence that DHA selectively induced the expansion of subsets of splenic T cells through phosphorylated CDKs and MAPK to enhance cellular immune responses under non-pathological or pathological conditions. The data significantly deepened our knowledge in the mechanism underlying DHA-mediated immunomodulation.

Dihydroartemisinin beneficially regulates splenic immune cell heterogeneity through the SOD3-JNK-AP-1 axis.

The immunomodulatory potential of dihydroartemisinin (DHA) has recently been highlighted; however, the potential mechanism remains to be clarified. Single-cell RNA sequencing was explored in combination with cellular and biochemical approaches to elucidate the immunomodulatory mechanisms of DHA. In this study, we found that DHA induced both spleen enlargement and rearrangement of splenic immune cell subsets in mice. It was revealed that DHA promoted the reversible expansion of effective regulatory T cells and interferon-γ+ cytotoxic CD8+ T cells in the spleen via induction of superoxide dismutase 3 (SOD3) expression and increased phosphorylation of c-Jun N-terminal kinases (JNK) and its downstream activator protein 1 (AP-1) transcription factors. Further, SOD3 knockout mice were resistant to the regulatory effect of DHA. Thus, DHA, through the activation of the SOD3-JNK-AP-1 axis, beneficially regulated immune cell heterogeneity and splenic immune cell homeostasis to treat autoimmune diseases.

Comparative analysis of ketone body metabolism in BALB/c mice infected with Trypanosoma evansi and Toxoplasma gondii.

KBs (ketone bodies), i.e., acetoacetate, acetone, and (R)-3-Hydroxybutanoate, constitute the intermediate products of the incomplete oxidative degradation of fatty acids. These KBs are used as a source of energy in the hosts' brain, skeletal muscles, and heart. Additionally, they regulate inflammation and oxidative stress of the host by acting as signaling mediators. Parasitic infection is known to result in abnormal physiological and biochemical metabolism, ketoacidosis, and other damage to the host. In this study, we investigated the effects of Trypanosoma evansi and Toxoplasma gondii on ketone body metabolism in mice, as well as the KB levels in the brain, liver, and peripheral blood. T. gondii was found to significantly increase the KB levels, resulting in ketonemia; T. evansi was found to stabilize KB levels in mice. Further investigations showed that T. evansi downregulated the expression of genes encoding enzymes involved in KBs synthesizing pathway and enhanced KBs synthesizing to eliminate ketonemia. Conversely, T. gondii significantly increased the expression of genes encoding enzymes involved in KBs synthesizing pathway and decreased KBs metabolism pathway ones and resulting in increased KBs levels in peripheral blood, culminating in ketonemia. These findings elucidate the differences in the KBs metabolism resulting from infection with T. evansi and T. gondii.

Protein Lactylation Critically Regulates Energy Metabolism in the Protozoan Parasite Trypanosoma brucei.

Lysine lactylation has been recognized as a novel post-translational modification occurring on histones. However, lactylation in non-histone proteins, especially in proteins of early branching organisms, is not well understood. Energy metabolism and the histone repertoire in the early diverging protozoan parasite Trypanosoma brucei, the causative agent of African trypanosomiasis, markedly diverge from those of conventional eukaryotes. Here, we present the first exhaustive proteome-wide investigation of lactylated sites in T. brucei. We identified 387 lysine-lactylated sites in 257 proteins of various cellular localizations and biological functions. Further, we revealed that glucose metabolism critically regulates protein lactylation in T. brucei although the parasite lacks lactate dehydrogenase. However, unlike mammals, increasing the glucose concentration reduced the level of lactate, and protein lactylation decreased in T. brucei via a unique lactate production pathway. In addition to providing a valuable resource, these foregoing data reveal the regulatory roles of protein lactylation of trypanosomes in energy metabolism and gene expression.