Anti-CRISPRs: Protein Inhibitors of CRISPR-Cas Systems.

Clustered regularly interspaced short palindromic repeats (CRISPR) together with their accompanying cas (CRISPR-associated) genes are found frequently in bacteria and archaea, serving to defend against invading foreign DNA, such as viral genomes. CRISPR-Cas systems provide a uniquely powerful defense because they can adapt to newly encountered genomes. The adaptive ability of these systems has been exploited, leading to their development as highly effective tools for genome editing. The widespread use of CRISPR-Cas systems has driven a need for methods to control their activity. This review focuses on anti-CRISPRs (Acrs), proteins produced by viruses and other mobile genetic elements that can potently inhibit CRISPR-Cas systems. Discovered in 2013, there are now 54 distinct families of these proteins described, and the functional mechanisms of more than a dozen have been characterized in molecular detail. The investigation of Acrs is leading to a variety of practical applications and is providing exciting new insight into the biology of CRISPR-Cas systems.

Continuous directed evolution of a compact CjCas9 variant with broad PAM compatibility.

CRISPR-Cas9 genome engineering is a powerful technology for correcting genetic diseases. However, the targeting range of Cas9 proteins is limited by their requirement for a protospacer adjacent motif (PAM), and in vivo delivery is challenging due to their large size. Here, we use phage-assisted continuous directed evolution to broaden the PAM compatibility of Campylobacter jejuni Cas9 (CjCas9), the smallest Cas9 ortholog characterized to date. The identified variant, termed evoCjCas9, primarily recognizes N4AH and N5HA PAM sequences, which occur tenfold more frequently in the genome than the canonical N3VRYAC PAM site. Moreover, evoCjCas9 exhibits higher nuclease activity than wild-type CjCas9 on canonical PAMs, with editing rates comparable to commonly used PAM-relaxed SpCas9 variants. Combined with deaminases or reverse transcriptases, evoCjCas9 enables robust base and prime editing, with the small size of evoCjCas9 base editors allowing for tissue-specific installation of A-to-G or C-to-T transition mutations from single adeno-associated virus vector systems.

The jet-like chromatin structure defines active secondary metabolism in fungi.

Eukaryotic genomes are spatially organized within the nucleus in a nonrandom manner. However, fungal genome arrangement and its function in development and adaptation remain largely unexplored. Here, we show that the high-order chromosome structure of Fusarium graminearum is sculpted by both H3K27me3 modification and ancient genome rearrangements. Active secondary metabolic gene clusters form a structure resembling chromatin jets. We demonstrate that these jet-like domains, which can propagate symmetrically for 54 kb, are prevalent in the genome and correlate with active gene transcription and histone acetylation. Deletion of GCN5, which encodes a core and functionally conserved histone acetyltransferase, blocks the formation of the domains. Insertion of an exogenous gene within the jet-like domain significantly augments its transcription. These findings uncover an interesting link between alterations in chromatin structure and the activation of fungal secondary metabolism, which could be a general mechanism for fungi to rapidly respond to environmental cues, and highlight the utility of leveraging three-dimensional genome organization in improving gene transcription in eukaryotes.

A novel RIPK1 inhibitor reduces GVHD in mice via a nonimmunosuppressive mechanism that restores intestinal homeostasis.

Intestinal epithelial cells (IECs) are implicated in the propagation of T-cell-mediated inflammatory diseases, including graft-versus-host disease (GVHD), but the underlying mechanism remains poorly defined. Here, we report that IECs require receptor-interacting protein kinase-3 (RIPK3) to drive both gastrointestinal (GI) tract and systemic GVHD after allogeneic hematopoietic stem cell transplantation. Selectively inhibiting RIPK3 in IECs markedly reduces GVHD in murine intestine and liver. IEC RIPK3 cooperates with RIPK1 to trigger mixed lineage kinase domain-like protein-independent production of T-cell-recruiting chemokines and major histocompatibility complex (MHC) class II molecules, which amplify and sustain alloreactive T-cell responses. Alloreactive T-cell-produced interferon gamma enhances this RIPK1/RIPK3 action in IECs through a JAK/STAT1-dependent mechanism, creating a feed-forward inflammatory cascade. RIPK1/RIPK3 forms a complex with JAK1 to promote STAT1 activation in IECs. The RIPK1/RIPK3-mediated inflammatory cascade of alloreactive T-cell responses results in intestinal tissue damage, converting the local inflammation into a systemic syndrome. Human patients with severe GVHD showed highly activated RIPK1 in the colon epithelium. Finally, we discover a selective and potent RIPK1 inhibitor (Zharp1-211) that significantly reduces JAK/STAT1-mediated expression of chemokines and MHC class II molecules in IECs, restores intestinal homeostasis, and arrests GVHD without compromising the graft-versus-leukemia (GVL) effect. Thus, targeting RIPK1/RIPK3 in IECs represents an effective nonimmunosuppressive strategy for GVHD treatment and potentially for other diseases involving GI tract inflammation.

HapX-mediated H2B deub1 and SreA-mediated H2A.Z deposition coordinate in fungal iron resistance.

Plant pathogens are challenged by host-derived iron starvation or excess during infection, but the mechanism through which pathogens counteract iron stress is unclear. Here, we found that Fusarium graminearum encounters iron excess during the colonization of wheat heads. Deletion of heme activator protein X (FgHapX), siderophore transcription factor A (FgSreA) or both attenuated virulence. Further, we found that FgHapX activates iron storage under iron excess by promoting histone H2B deubiquitination (H2B deub1) at the promoter of the responsible gene. Meanwhile, FgSreA is shown to inhibit genes mediating iron acquisition during iron excess by facilitating the deposition of histone variant H2A.Z and histone 3 lysine 27 trimethylation (H3K27 me3) at the first nucleosome after the transcription start site. In addition, the monothiol glutaredoxin FgGrx4 is responsible for iron sensing and control of the transcriptional activity of FgHapX and FgSreA via modulation of their enrichment at target genes and recruitment of epigenetic regulators, respectively. Taken together, our findings elucidated the molecular mechanisms for adaptation to iron excess mediated by FgHapX and FgSreA during infection in F. graminearum and provide novel insights into regulation of iron homeostasis at the chromatin level in eukaryotes.

Electronically Reconfigurable Memristive Neuron Capable of Operating in Both Excitation and Inhibition Modes.

Threshold switching (TS) memristors are promising candidates for artificial neurons in neuromorphic systems. However, they often lack biological plausibility, typically functioning solely in an excitation mode. The absence of an inhibitory mode limits neurons' ability to synergistically process both excitatory and inhibitory synaptic signals. To address this limitation, we propose a novel memristive neuron capable of operating in both excitation and inhibition modes. The memristor's threshold voltage can be reversibly tuned using voltages of different polarities because of its bipolar TS behavior, enabling the device to function as an electronically reconfigurable bi-mode neuron. A variety of neuronal activities such as all-or-nothing behavior and tunable firing probability are mimicked under both excitatory and inhibitory stimuli. Furthermore, we develop a self-adaptive neuromorphic vision sensor based on bi-mode neurons, demonstrating effective object recognition in varied lighting conditions. Thus, our bi-mode neuron offers a versatile platform for constructing neuromorphic systems with rich functionality.

The novel small molecule E0924G dually regulates bone formation and bone resorption through activating the PPARδ signaling pathway to prevent bone loss in ovariectomized rats and senile mice.

Osteoporosis is particularly prevalent among postmenopausal women and the elderly. In the present study, we investigated the effect of the novel small molecule E0924G (N-(4-methoxy-pyridine-2-yl)-5-methylfuran-2-formamide) on osteoporosis. E0924G significantly increased the protein expression levels of osteoprotegerin (OPG) and runt-related transcription factor 2 (RUNX2), and thus significantly promoted osteogenesis in MC3T3-E1 cells. E0924G also significantly decreased osteoclast differentiation and inhibited bone resorption and F-actin ring formation in receptor activator of NF-κB ligand (RANKL)-induced osteoclasts from RAW264.7 macrophages. Importantly, oral administration of E0924G in both ovariectomized (OVX) rats and SAMP6 senile mice significantly increased bone mineral density and decreased bone loss compared to OVX controls or SAMR1 mice. Further mechanistic studies showed that E0924G could bind to and then activate peroxisome proliferator-activated receptor delta (PPARδ), and the pro-osteoblast effect and the inhibition of osteoclast differentiation induced by E0924G were significantly abolished when PPARδ was knocked down or inhibited. In conclusion, these data strongly suggest that E0924G has the potential to prevent OVX-induced and age-related osteoporosis by dual regulation of bone formation and bone resorption through activation of the PPARδ signaling pathway.

Association between polypharmacy and chronic kidney disease among community-dwelling older people: a longitudinal study in southern China.

BACKGROUND: Polypharmacy would increase the risk of adverse drug events and the burden of renal drug excretion among older people. Nevertheless, the association between the number of medication and the risk of chronic kidney disease (CKD) remains controversial. Therefore, this study aims to investigate the association between the number of medication and the incidence of CKD in older people. METHODS: This study investigates the association between the number of medications and CKD in 2672 elderly people (≥ 65 years older) of the community health service center in southern China between 2019 and 2022. Logistic regression analysis was used to evaluate the relationship between polypharmacy and CKD. RESULTS: At baseline, the average age of the study subjects was 71.86 ± 4.60, 61.2% were females, and 53 (2.0%) suffer from polypharmacy. During an average follow-up of 3 years, new-onset CKD developed in 413 (15.5%) participants. Logistic regression analysis revealed that taking a higher number of medications was associated with increase of CKD. Compared with people who didn't take medication, a higher risk of CKD was observed in the older people who taken more than five medications (OR 3.731, 95% CI 1.988, 7.003), followed by those who take four (OR 1.621, 95% CI 1.041, 2.525), three (OR 1.696, 95% CI 1.178, 2.441), two drugs (OR 1.585, 95% CI 1.167, 2.153), or one drug (OR 1.503, 95% CI 1.097, 2.053). Furthermore, age, systolic blood pressure (SBP), white blood cell (WBC), blood urea nitrogen (BUN) and triglyceride (TG) were also independent risk factors CKD (P < 0.05). CONCLUSION: The number of medications was associated with CKD in older people. As the number of medications taken increased, the risk of CKD was increased.

Atroposelective Formal [2 + 5] Macrocyclization Synthesis for a Novel All-Hydrocarbon Cyclo[7] Meta-Benzene Macrocycle.

A novel axially chiral all-hydrocarbon cyclo[7] (1,3-(4,6-dimethyl)benzene (CDMB-7) was designed and synthesized using atroposelective[2 + 5] cyclization through Suzuki-Miyaura coupling. CDMB-7 adopts an irregular bowl-like shape with C2 symmetry and exhibits two diastereoisomers in its crystallographic structure. The conformational isomers of CDMB-7 racemates remain stable at high temperatures (393 K). High-performance liquid chromatography (HPLC) confirmed that a single chiral isomer will spontaneously undergo racemization within 30 min at room temperature. This finding opens up possibilities for achieving adaptive chirality in all-hydrocarbon cyclo[7] m-benzene macrocycles.

Transcriptional insights of citrus defense response against Diaporthe citri.

Citrus melanose, caused by Diaporthe citri, is one of the most important and widespread fungal diseases of citrus. Previous studies demonstrated that the citrus host was able to trigger the defense response to restrict the spread of D. citri. However, the molecular mechanism underlying this defense response has yet to be elucidated. Here, we used RNA-Seq to explore the gene expression pattern at the early (3 days post infection, dpi) and late (14 dpi) infection stages of citrus leaves in response to D. citri infection, and outlined the differences in transcriptional regulation associated with defense responses. The functional enrichment analysis indicated that the plant cell wall biogenesis was significantly induced at the early infection stage, while the callose deposition response was more active at the late infection stage. CYP83B1 genes of the cytochrome P450 family were extensively induced in the callus deposition-mediated defense response. Remarkably, the gene encoding pectin methylesterase showed the highest upregulation and was only found to be differentially expressed at the late infection stage. Genes involved in the synthesis and regulation of phytoalexin coumarin were effectively activated. F6'H1 and S8H, encoding key enzymes in the biosynthesis of coumarins and their derivatives, were more strongly expressed at the late infection stage than at the early infection stage. Collectively, our study profiled the response pattern of citrus leaves against D. citri infection and provided the transcriptional evidence to support the defense mechanism.

The predictive value of the modified AFP model for liver transplantation outcomes in multinodular hepatocellular carcinoma patients.

BACKGROUND: There is a lack of studies focusing on the benefit of liver transplantation (LT) in hepatocellular carcinoma (HCC) patients with > 3 tumors. This study aims to establish a model to effectively predict overall survival in Chinese HCC patients with multiple tumors (> 3 tumors) who undergo LT. METHODS: This retrospective study included 434 HCC liver transplant recipients from the China Liver Transplant Registry. All HCC patients had more than 3 tumor nodules. Three selection criteria systems (i.e., AFP, Metroticket 2.0, and Up-to-7) were compared regarding the prediction of HCC recurrence. The modified AFP model was established by univariate and multivariate competing risk analyses. RESULTS: The AFP score 2 and the AFP score ≥ 3 groups had 5-year recurrence rates of 19.6% and 40.5% in our cohort. The prediction of HCC recurrence based on the AFP model was associated with a c-statistic of 0.606, which was superior to the Up-to-7 and Metroticket 2.0 models. AFP level > 1000 ng/mL, largest tumor size ≥ 8 cm, vascular invasion, and MELD score ≥ 15 were associated with overall survival. The 5-year survival rate in the modified AFP score 0 group was 71.7%. CONCLUSIONS: The AFP model is superior in predicting tumor recurrence in HCC patients with > 3 tumors prior to LT. With the modified AFP model, patients likely to derive sufficient benefit from LT can be identified.

[Urine metabolomics study of intervention of Xihuang Pills in rats with hyperplasia of mammary gland].

This study aimed to investigate the mechanism of Xihuang Pills in improving hyperplasia of mammary gland(HMG) in rats based on urine metabolomics using ultra-performance liquid chromatography-quadrupole-Orbitrap mass spectrometry(UPLC-Q-Orbitrap-MS). The HMG rat model was established by intramuscular injection of estradiol benzoate solution(0.5 mg·kg~(-1), 25 days) followed by progesterone injection(5 mg·kg~(-1), 5 days). UPLC-Q-Orbitrap-MS technology was used to establish the endogenous small-molecule metabolic profiles in urine samples of rats in the blank group, the HMG model group, and Xihuang Pills group. Multivariate statistical analysis was performed for pattern recognition, t test and variable importance in the projection(VIP) were used to screen potential biomarkers. The significantly changed differential metabolites were identified using the online database Human Metabolome Database(HMDB). Metabolic pathway enrichment analysis was conducted using the MetaboAnalyst 5.0 database. The results showed that 90 differential metabolites with significant changes(P<0.05) were identified between the blank group and the HMG model group using the HMDB. Among them, 48 metabolites significantly reverted(P<0.05) after administration of Xihuang Pills, which may be related to the regulatory effect of Xihuang Pills. Thirteen metabolic pathways significantly associated with HMG were identified when the differential metabolites were imported into the MetaboAnalyst 5.0 database, and Xihuang Pills could modulate seven of these pathways. These metabolic pathways mainly involved histidine metabolism, arginine and proline metabolism, ß-alanine metabolism, glycine, serine and threonine metabolism, tryptophan metabolism, pyrimidine metabolism, and amino sugar and nucleotide sugar metabolism. This study utilized UPLC-Q-Orbitrap-MS and urine metabolomics technology to analyze the mechanism of Xihuang Pills in improving HMG, laying the foundation for further in-depth research.

[Mechanism of blood-activating and mass-dissipating Chinese patent medicine against hyperplasia of mammary glands and use with other medicine: a review].

Caused by endocrine disorder, hyperplasia of mammary glands(HMG) tends to occur in the young with increasing incidence, putting patients at the risk of cancer and threatening the health of women. Therefore, the prevention and treatment of HMG is attracting more and more attention. Amid the modernization of traditional Chinese medicine(TCM), many scholars have found that Chinese patent medicine has unique advantages and huge potential in treatment of endocrine disorder. Particularly, Chinese patent medicine with the function of blood-activating and mass-dissipating, such as Xiaojin Pills and Xiaozheng Pills, has been commonly used in clinical treatment of HMG, which features multiple targets, obvious efficacy, small side effect, and ease of taking and carrying around. Clinical studies have found that the combination of Chinese patent medicine with other medicine can not only improve the efficacy and relieve symptoms such as hyperplasia and pain but also reduce the toxic and side effects of western medicine. Therefore, based on precious pharmacological research and clinical research, this study reviewed the mechanisms of blood-activating mass-dissipating Chinese patent medicine alone and in combination with other medicine, such as regulating levels of in vivo hormones and receptors, promoting apoptosis, inhibiting angiogenesis, improving hemorheology indexes, enhancing immunity, and boosting antioxidant ability. In addition, limitations and problems were summarized. Thereby, this study is expected to lay a theoretical basis for the further study and clinical application of blood-activating mass-dissipating Chinese patent medicine alone or in combination with other medicine against HMG.

[Mechanism of anti-hyperplasia of mammary glands of Xihuang Pills blood-entering component based on UPLC-Q-TOF-MS and network pharmacology].

In this study, based on network pharmacology and molecular docking method, the mechanism of anti-hyperplasia of mammary glands of Xihuang Pills blood-entering components was explored, and the efficacy and key targets of Xihuang Pills blood-entering components were experimentally verified by MCF-10A proliferation model of human mammary epithelial cells. In order to clarify the material basis and mechanism of Xihuang Pills in realizing anti-hyperplasia of mammary glands, the blood-entering components of Xihuang Pills were qualitatively analyzed by UPLC-Q-TOF-MS, and 22 blood-entering components were identified. By taking the blood-entering components as the research object, the network pharmacology prediction and molecular docking verification were carried out, and finally, three key targets were screened out, namely JAK1, SRC, and CDK1. In vitro experiments show that Xihuang Pills can inhibit the proliferation of MCF-10A cells, promote the apoptosis of MCF-10A cells, and reduce the expression of JAK1, SRC, and CDK1 targets in cells. To sum up, Xihuang Pills can promote the apoptosis of mammary epithelial cells by regulating the expression of JAK1, SRC, and CDK1 and then play an anti-hyperplasia role, which provides an experimental basis for clarifying the material basis of Xihuang Pills for anti-hyperplasia effect.

E2F7 promotes mammalian target of rapamycin inhibitor resistance in hepatocellular carcinoma after liver transplantation.

The mammalian target of rapamycin (mTOR) pathway is frequently deregulated and has critical roles in cancer progression. mTOR inhibitor has been widely used in several kinds of cancers and is strongly recommended in patients with hepatocellular carcinoma (HCC) after liver transplantation (LT). However, the poor response to mTOR inhibitors due to resistance remains a challenge. Hypoxia-associated resistance limits the therapeutic efficacy of targeted drugs. The present study established models of HCC clinical samples and cell lines resistance to mTOR inhibitor sirolimus and screened out E2F7 as a candidate gene induced by hypoxia and promoting sirolimus resistance. E2F7 suppressed mTOR complex 1 via directly binding to the promoter of the TSC1 gene and stabilizes hypoxia-inducible factor-1α activating its downstream genes, which are responsible for E2F7-dependent mTOR inhibitor resistance. Clinically, low E2F7 expression could be an effective biomarker for recommending patients with HCC for anti-mTOR-based therapies after LT. Targeting E2F7 synergistically inhibited HCC growth with sirolimus in vivo. E2F7 is a promising target to reverse mTOR inhibition resistance. Collectively, our study points to a role for E2F7 in promoting mTOR inhibitor resistance in HCC and emphasizes its potential clinical significance in patients with HCC after LT.

Novel γδ T cell-based prognostic signature to estimate risk and aid therapy in hepatocellular carcinoma.

BACKGROUND: Numerous studies have revealed that gamma delta (γδ) T cell infiltration plays a crucial regulatory role in hepatocellular carcinoma (HCC) development. Nonetheless, a comprehensive analysis of γδ T cell infiltration in prognosis evaluation and therapeutic prediction remains unclear. METHODS: Multi-omic data on HCC patients were obtained from public databases. The CIBERSORT algorithm was applied to decipher the tumor immune microenvironment (TIME) of HCC. Weighted gene co-expression network analysis (WGCNA) was performed to determine significant modules with γδ T cell-specific genes. Kaplan-Meier survival curves and receiver operating characteristic analyses were used to validate prognostic capability. Additionally, the potential role of RFESD inhibition by si-RFESD in vitro was investigated using EdU and CCK-8 assays. RESULTS: A total of 16,421 genes from 746 HCC samples (616 cancer and 130 normal) were identified based on three distinct cohorts. Using WGCNA, candidate modules (brown) with 1755 significant corresponding genes were extracted as γδ T cell-specific genes. Next, a novel risk signature consisting of 11 hub genes was constructed using multiple bioinformatic analyses, which presented great prognosis prediction reliability. The risk score exhibited a significant correlation with ICI and chemotherapeutic targets. HCC samples with different risks experienced diverse signalling pathway activities. The possible interaction of risk score with tumor mutation burden (TMB) was further analyzed. Subsequently, the potential functions of the RFESD gene were explored in HCC, and knockdown of RFESD inhibited cell proliferation in HCC cells. Finally, a robust prognostic risk-clinical nomogram was developed and validated to quantify clinical outcomes. CONCLUSIONS: Collectively, comprehensive analyses focusing on γδ T cell patterns will provide insights into prognosis prediction, the mechanisms of immune infiltration, and advanced therapy strategies in HCC.

Design, synthesis, and structure-activity relationship of novel RIPK2 inhibitors.

The NOD1/2 (nucleotide-binding oligomerization domain-containing protein 1/2) signaling pathways are involved in innate immune control and host defense. NOD dysfunction can result in a variety of autoimmune disorders. NOD-induced generation of inflammatory cytokines is mediated by receptor-interacting protein kinase 2 (RIPK2), which has been considered as a promising therapeutic target. Herein, we disclose the design, synthesis, and SAR study of a series of RIPK2 inhibitors. The lead compound 17 displayed a high affinity for RIPK2 (Kd = 5.9 nM) and was capable of inhibiting RIPK2 kinase function in an ADP-Glo assay. In vitro DMPK studies showed that compound 17 had good metabolic stability and no CYP inhibition. Compound 17 effectively suppressed inflammatory cytokine production in both cells and animal model.

Biological and molecular characterizations of field fludioxonil-resistant isolates of Fusarium graminearum.

Fusarium head blight (FHB) predominately caused by F. graminearum, is an economical devastating disease for grain cereal crops especially on wheat. The phenylpyrrole fungicide fludioxonil exhibits excellent activity against F. graminearum and has been registered to control FHB in China. In this study, 6 fludioxonil-resistant (FludR) isolates of F. graminearum were identified from 2910 isolates collected from wheat cultivated field in Jiang Su, An Hui and Henan province of China in 2020. The sensitivity assay showed that resistance factor (RF) of FludR isolates ranges from 170.73 to >1000. In comparison with fludioxonil-sensitive (FludS) isolates, all of FludR isolates showed fitness defects in terms of mycelial growth, conidiation and virulence. Under fludioxonil treatment condition, the glycerol accumulation was obviously increased in FludS isolates, but was slightly increased in FludR isolates. Four FludR isolates exhibited increased sensitivity to osmotic stresses. Moreover, there is no positive cross-resistance between fludioxonil and other fungicides including phenamacril, carbendazim and tebuconazole. When treated with fludioxonil, the phosphorylation level of Hog1 was significantly decreased in the four FludR isolates, which was in contrast to the observation in the FludS and two FludR isolates where phosphorylation level of Hog1 was increased. Sequencing assay showed that the mutations were identified in different domains in FgOS1, FgOS2 or FgOS4 in FludR isolates. This was first reported that biological and molecular characterizations of field isolates of F. graminearum resistant to fludioxonil. The results can provide scientific directions for controlling FHB using fludioxonil.

Autophagy-Related Gene PlATG6a Is Involved in Mycelial Growth, Asexual Reproduction and Tolerance to Salt and Oxidative Stresses in Peronophythora litchii.

Autophagy is ubiquitously present in eukaryotes. During this process, intracellular proteins and some waste organelles are transported into lysosomes or vacuoles for degradation, which can be reused by the cell to guarantee normal cellular metabolism. However, the function of autophagy-related (ATG) proteins in oomycetes is rarely known. In this study, we identified an autophagy-related gene, PlATG6a, encoding a 514-amino-acid protein in Peronophythora litchii, which is the most destructive pathogen of litchi. The transcriptional level of PlATG6a was relatively higher in mycelium, sporangia, zoospores and cysts. We generated PlATG6a knockout mutants using CRISPR/Cas9 technology. The P. litchii Δplatg6a mutants were significantly impaired in autophagy and vegetative growth. We further found that the Δplatg6a mutants displayed decreased branches of sporangiophore, leading to impaired sporangium production. PlATG6a is also involved in resistance to oxidative and salt stresses, but not in sexual reproduction. The transcription of peroxidase-encoding genes was down-regulated in Δplatg6a mutants, which is likely responsible for hypersensitivity to oxidative stress. Compared with the wild-type strain, the Δplatg6a mutants showed reduced virulence when inoculated on the litchi leaves using mycelia plugs. Overall, these results suggest a critical role for PlATG6a in autophagy, vegetative growth, sporangium production, sporangiophore development, zoospore release, pathogenesis and tolerance to salt and oxidative stresses in P. litchii.

Short chain fatty acids inhibit endotoxin-induced uveitis and inflammatory responses of retinal astrocytes.

Short chain fatty acids (SCFAs) are produced by gut microbiota as fermentation products of digestion-resistant oligosaccharides and fibers. Their primary roles are functioning as major energy sources for colon cells and assisting in gut homeostasis by immunomodulation. Recent evidence suggests that they affect various organs both at cellular and molecular levels, and regulate functions in distance sites including gene expression, cell proliferation, cell differentiation, apoptosis and inflammation. In this study, we examined whether SCFAs are present in the mouse eye and whether SCFAs affect inflammatory responses of the eye and retinal astrocytes (RACs). We observed that intra-peritoneal injected SCFAs were detected in the eye and reduced intraocular inflammation induced by lipopolysaccharide (LPS). Moreover, SCFAs displayed two disparate effects on LPS-stimulated RACs - namely, cytokine and chemokine production was reduced, but the ability to activate T cells was enhanced. Our results support the existence of gut-eye cross talk and suggest that SCFAs can cross the blood-eye-barrier via the systemic circulation. If applied at high concentrations, SCFAs may reduce inflammation and impact cellular functions in the intraocular milieu.