Nosema bombycis: A remarkable unicellular parasite infecting insects

Microsporidia are opportunistic fungal-like pathogens that cause microsporidiosis, which results in significant economic losses and threatens public health. Infection of domesticated silkworms by the microsporidium Nosema bombycis causes pébrine disease, for which this species of microsporidia has received much attention. Research has been conducted extensively on this microsporidium over the past few decades to better understand its infection, transmission, host-parasite interaction, and detection. Several tools exist to study this species including the complete genome sequence of N. bombycis. In addition to the understanding of N. bombycis being important for the silkworm industry, this species has become a model organism for studying microsporidia. Research on biology of N. bombycis will contribute to the development of knowledge regarding microsporidia and potential antimicrosporidia drugs. Furthermore, this will provide insight into the molecular evolution and functioning of other fungal pathogens.

Bioactive Metal Ion-Coordinated Dynamic Hydrogel with Antibacterial, Immunomodulatory, and Angiogenic Activities for Infected Wound Repair

The repair of infected wounds is a complex physiopathologic process. Current studies on infected wound treatment have predominantly focused on infection treatment, while the factors related to delayed healing caused by vascular damage and immune imbalance are commonly overlooked. In this study, an extracellular matrix (ECM)-like dynamic and multifunctional hyaluronic acid (HA) hydrogel with antimicrobial, immunomodulatory, and angiogenic capabilities was designed as wound dressing for the treatment of infected skin wounds. The dynamic network in the hydrogel dressing was based on reversible metal-ligand coordination formed between sulfhydryl groups and bioactive metal ions. In our design, antibacterial silver and immunomodulatory zinc ions were employed to coordinate with sulfhydrylated HA and a vasculogenic peptide. In addition to the desired bioactivities for infected wounds, the hydrogel could also exhibit self-healing and injectable abilities. Animal experiments with infected skin wound models indicated that the hydrogel dressings enabled minimally invasive injection and seamless skin wound covering and then facilitated wound healing by efficient bacterial killing, continuous inflammation inhibition, and improved blood vessel formation. In conclusion, the metal ion-coordinated hydrogels with wound-infection-desired bioactivities and ECM-like dynamic structures represent a class of tissue bionic wound dressings for the treatment of infected and chronic inflammation wounds.

Case report: The diagnostic pitfall of Warthin-like mucoepidermoid carcinoma

Warthin-like mucoepidermoid carcinoma (WL-MEC) is a newly reported variant of mucoepidermoid carcinoma. Its histological feature is easy to confused with metaplastic Warthin Tumor, and its relationship with Warthin tumor in histogenesis is controversial. In this study, we presented two cases of WL-MEC, discussing their clinicopathological and molecular features. Notably, one case was initially misdiagnosed during the first onset of the tumor. Case 1 was a 60-year-old female with a mass in the right parotid gland. Case 2 featured a 29-year-old male who developed a lump at the original surgical site 6 months after a "Warthin tumor" resection from the submandibular gland. Histologically, both tumor exhibited a prominent lymphoid stroma and cystic pattern, accompanied by various amounts of epithelial nests composed of squamoid cells, intermediate cells and mucinous cells. The characteristic eosinophilic bilayer epithelium of Warthin tumor was not typically presented in either case. Both cases tested positive for MAML2 gene rearrangement. To contextualize our findings, we conducted a comprehensive review of forty-eight WL-MEC cases documented in the English literature, aiming to synthesizing a reliable differential diagnostic approach. WL-MEC is a rare yet clinically relevant variant, posing a diagnostic pitfall for pathologists. Our study underscores the importance of a meticulous evaluation of both clinical and histological features, coupled with the detection of MAML2 rearrangement, as a credible method for distinguishing WL-MEC from other benign and malignant lesions, particularly metaplastic Warthin tumor.

Tailor-made molecular imprints for biological event intervention

Molecular imprints, which are crosslinked architectures containing specific molecular recognition cavities for targeting compounds, have recently transitioned from in vitro diagnosis to in vivo treatment. In current application scenarios, it has become an important topic to create new biomolecular recognition pathways through molecular imprinting, thereby inhibiting the pathogenesis and regulating the development of diseases. This review starts with a pathological analysis, mainly focusing on the corresponding artificial enzymes, enzyme inhibitors and antibody mimics with enhanced functions that are created by molecular imprinting strategies. Recent advances are highlighted in the use of molecular imprints as tailor-made nanomedicines for the prevention of three major diseases: metabolic syndrome, cancer, and bacterial/viral infections.

E. hellem Ser/Thr protein phosphatase PP1 targets the DC MAPK pathway and impairs immune functions

Microsporidia are difficult to be completely eliminated once infected, and the persistence disrupts host cell functions. Here in this study, we aimed to elucidate the impairing effects and consequences of microsporidia on host DCs. Enterocytozoon hellem, one of the most commonly diagnosed zoonotic microsporidia species, was applied. In vivo models demonstrated that E. hellem-infected mice were more susceptible to further pathogenic challenges, and DCs were identified as the most affected groups of cells. In vitro assays revealed that E. hellem infection impaired DCs' immune functions, reflected by down-regulated cytokine expressions, lower extent of maturation, phagocytosis ability, and antigen presentations. E. hellem infection also detained DCs' potencies to prime and stimulate T cells; therefore, host immunities were disrupted. We found that E. hellem Ser/Thr protein phosphatase PP1 directly interacts with host p38α (MAPK14) to manipulate the p38α(MAPK14)/NFAT5 axis of the MAPK pathway. Our study is the first to elucidate the molecular mechanisms of the impairing effects of microsporidia on host DCs' immune functions. The emergence of microsporidiosis may be of great threat to public health.

Transcriptomic changes in the microsporidia proliferation and host responses in congenitally infected embryos and larvae

Congenital infection caused by vertical transmission of microsporidia N. bombycis can result in severe economic losses in the silkworm-rearing industry. Whole-transcriptome analyses have revealed non-coding RNAs and their regulatory networks in N. bombycis infected embryos and larvae. However, transcriptomic changes in the microsporidia proliferation and host responses in congenitally infected embryos and larvae remains unclear. Here, we simultaneously compared the transcriptomes of N. bombycis and its host B. mori embryos of 5-day and larvae of 1-, 5- and 10-day during congenital infection. For the transcriptome of N. bombycis, a comparison of parasite expression patterns between congenital-infected embryos and larva showed most genes related to parasite central carbon metabolism were down-regulated in larvae during infection, whereas the majority of genes involved in parasite proliferation and growth were up-regulated. Interestingly, a large number of distinct or shared differentially expressed genes (DEGs) were revealed by the Venn diagram and heat map, many of them were connected to infection related factors such as Ricin B lectin, spore wall protein, polar tube protein, and polysaccharide deacetylase. For the transcriptome of B. mori infected with N. bombycis, beyond numerous DEGs related to DNA replication and repair, mRNA surveillance pathway, RNA transport, protein biosynthesis, and proteolysis, with the progression of infection, a large number of DEGs related to immune and infection pathways, including phagocytosis, apoptosis, TNF, Toll-like receptor, NF-kappa B, Fc epsilon RI, and some diseases, were successively identified. In contrast, most genes associated with the insulin signaling pathway, 2-oxacarboxylic acid metabolism, amino acid biosynthesis, and lipid metabolisms were up-regulated in larvae compared to those in embryos. Furthermore, dozens of distinct and three shared DEGs that were involved in the epigenetic regulations, such as polycomb, histone-lysine-specific demethylases, and histone-lysine-N-methyltransferases, were identified via the Venn diagram and heat maps. Notably, many DEGs of host and parasite associated with lipid-related metabolisms were verified by RT-qPCR. Taken together, simultaneous transcriptomic analyses of both host and parasite genes lead to a better understanding of changes in the microsporidia proliferation and host responses in embryos and larvae in N. bombycis congenital infection.

Identification of Parkinson's disease subtypes with distinct brain atrophy progression and its association with clinical progression

Background

Parkinson's disease (PD) patients suffer from progressive gray matter volume (GMV) loss, but whether distinct patterns of atrophy progression exist within PD are still unclear.

Objective

This study aims to identify PD subtypes with different rates of GMV loss and assess their association with clinical progression.

Methods

This study included 107 PD patients (mean age: 60.06 ± 9.98 years, 70.09% male) with baseline and ≥ 3-year follow-up structural MRI scans. A linear mixed-effects model was employed to assess the rates of regional GMV loss. Hierarchical cluster analysis was conducted to explore potential subtypes based on individual rates of GMV loss. Clinical score changes were then compared across these subtypes.

Results

Two PD subtypes were identified based on brain atrophy rates. Subtype 1 (n = 63) showed moderate atrophy, notably in the prefrontal and lateral temporal lobes, while Subtype 2 (n = 44) had faster atrophy across the brain, particularly in the lateral temporal region. Furthermore, subtype 2 exhibited faster deterioration in non-motor (MDS-UPDRS-Part Ⅰ, β = 1.26 ± 0.18, P = 0.016) and motor (MDS-UPDRS-Part Ⅱ, β = 1.34 ± 0.20, P = 0.017) symptoms, autonomic dysfunction (SCOPA-AUT, β = 1.15 ± 0.22, P = 0.043), memory (HVLT-Retention, β = -0.02 ± 0.01, P = 0.016) and depression (GDS, β = 0.26 ± 0.083, P = 0.019) compared to subtype 1.

Conclusion

The study has identified two PD subtypes with distinct patterns of atrophy progression and clinical progression, which may have implications for developing personalized treatment strategies.

Microsporidia dressing up: the spore polaroplast transport through the polar tube and transformation into the sporoplasm membrane

Microsporidia are obligate intracellular parasites that infect a wide variety of hosts including humans. Microsporidian spores possess a unique, highly specialized invasion apparatus involving the polar filament, polaroplast, and posterior vacuole. During spore germination, the polar filament is discharged out of the spore forming a hollow polar tube that transports the sporoplasm components including the nucleus into the host cell. Due to the complicated topological changes occurring in this process, the details of sporoplasm formation are not clear. Our data suggest that the limiting membrane of the nascent sporoplasm is formed by the polaroplast after microsporidian germination. Using electron microscopy and 1,1'-dioctadecyl-3,3,3',3' tetramethyl indocarbocyanine perchlorate staining, we describe that a large number of vesicles, nucleus, and other cytoplasm contents were transported out via the polar tube during spore germination, while the posterior vacuole and plasma membrane finally remained in the empty spore coat. Two Nosema bombycis sporoplasm surface proteins (NbTMP1 and NoboABCG1.1) were also found to localize in the region of the polaroplast and posterior vacuole in mature spores and in the discharged polar tube, which suggested that the polaroplast during transport through the polar tube became the limiting membrane of the sporoplasm. The analysis results of Golgi-tracker green and Golgi marker protein syntaxin 6 were also consistent with the model of the transported polaroplast derived from Golgi transformed into the nascent sporoplasm membrane.IMPORTANCEMicrosporidia, which are obligate intracellular pathogenic organisms, cause huge economic losses in agriculture and even threaten human health. The key to successful infection by the microsporidia is their unique invasion apparatus which includes the polar filament, polaroplast, and posterior vacuole. When the mature spore is activated to geminate, the polar filament uncoils and undergoes a rapid transition into the hollow polar tube that transports the sporoplasm components including the microsporidian nucleus into host cells. Details of the structural difference between the polar filament and polar tube, the process of cargo transport in extruded polar tube, and the formation of the sporoplasm membrane are still poorly understood. Herein, we verify that the polar filament evaginates to form the polar tube, which serves as a conduit for transporting the nucleus and other sporoplasm components. Furthermore, our results indicate that the transported polaroplast transforms into the sporoplasm membrane during spore germination. Our study provides new insights into the cargo transportation process of the polar tube and origin of the sporoplasm membrane, which provide important clarification of the microsporidian infection mechanism.

Microsporidia persistence in host impairs epithelial barriers and increases chances of inflammatory bowel disease

Microsporidia are intracellular fungus-like pathogens and the infection symptoms include recurrent diarrhea and systematic inflammations. The major infection route of microsporidia is the digestive tract. Since microsporidia are hard to fully eliminate, the interactions and persistence of the pathogen within epithelium may modulate host susceptibility to digestive disorders. In this study, both in vitro and in vivo infection models were applied. The alterations of epithelial barrier integrity, permeability, and tight junction proteins after microsporidia infection were assessed on MDCK/Caco-2 monolayers. The fecal intestinal microbiota and tissue alterations after microsporidia infection were assessed on C57BL/6 mice. Moreover, the susceptibility to develop dextran sulfate sodium (DSS)-induced inflammatory bowel diseases (IBDs) was also analyzed by the murine infection model. The results demonstrated that microsporidia infection increased epithelium permeability, weakened wound healing capability, and destructed tight junction protein zonula occludens-1. Microsporidia infection also dysregulates intestinal microbiota. These impairing effects of microsporidia increased host vulnerability to develop enteritis as shown by the murine model of DSS-induced IBD. Our study is the first to elucidate molecular mechanisms of the damaging effects of microsporidia on host epithelium and pointed out the cryptic threats of latent microsporidia infection to public health as reflected by the increased chances of developing more severe diseases.IMPORTANCEMicrosporidia are widely present in nature and usually cause latent and persistent infections in hosts. Given the fact that the digestive tract is the major infection route, it is of great importance to explore the consequences of microsporidia infection on the intestinal epithelial barrier and the risks to the host. In this study, we demonstrated the destructing effects of microsporidium infection on epithelial barriers manifested as increased epithelial permeability, weakened wound healing ability, and disrupted tight junctions. Moreover, microsporidia made the host more susceptible to dextran sulfate sodium-induced inflammatory bowel disease. These findings provide new evidence for us to better understand and develop novel strategies for microsporidia prevention and disease control.

An Oral Nanomedicine Elicits In Situ Vaccination Effect against Colorectal Cancer

Oral administration is the most preferred approach for treating colon diseases, and in situ vaccination has emerged as a promising cancer therapeutic strategy. However, the lack of effective drug delivery platforms hampered the application of in situ vaccination strategy in oral treatment of colorectal cancer (CRC). Here, we construct an oral core-shell nanomedicine by preparing a silk fibroin-based dual sonosensitizer (chlorin e6, Ce6)- and immunoadjuvant (imiquimod, R837)-loaded nanoparticle as the core, with its surface coated with plant-extracted lipids and pluronic F127 (p127). The resultant nanomedicines (Ce6/R837@Lp127NPs) maintain stability during their passage through the gastrointestinal tract and exert improved locomotor activities under ultrasound irradiation, achieving efficient colonic mucus infiltration and specific tumor penetration. Thereafter, Ce6/R837@Lp127NPs induce immunogenic death of colorectal tumor cells by sonodynamic treatment, and the generated neoantigens in the presence of R837 serve as a potent in situ vaccine. By integrating with immune checkpoint blockades, the combined treatment modality inhibits orthotopic tumors, eradicates distant tumors, and modulates intestinal microbiota. As the first oral in situ vaccination, this work spotlights a robust oral nanoplatform for producing a personalized vaccine against CRC.

Harnessing multiplex crRNA enables an amplification-free/CRISPR-Cas12a-based diagnostic methodology for Nosema bombycis

IMPORTANCE

The multiplex-crRNA CRISPR/Cas12a detection method saves hands-on time, reduces the risk of aerosol pollution, and can be directly applied to detecting silkworms infected with Nosema bombycis. This study provides a new approach for the inspection and quarantine of silkworm pébrine disease in sericulture and provides a new method for the detection of other pathogens.

SilkMeta: a comprehensive platform for sharing and exploiting pan-genomic and multi-omic silkworm data

The silkworm Bombyx mori is a domesticated insect that serves as an animal model for research and agriculture. The silkworm super-pan-genome dataset, which we published last year, is a unique resource for the study of global genomic diversity and phenotype-genotype association. Here we present SilkMeta (http://silkmeta.org.cn), a comprehensive database covering the available silkworm pan-genome and multi-omics data. The database contains 1082 short-read genomes, 546 long-read assembled genomes, 1168 transcriptomes, 294 phenotype characterizations (phenome), tens of millions of variations (variome), 7253 long non-coding RNAs (lncRNAs), 18 717 full length transcripts and a set of population statistics. We have compiled publications on functional genomics research and genetic stock deciphering (mutant map). A range of bioinformatics tools is also provided for data visualization and retrieval. The large batch of omics data and tools were integrated in twelve functional modules that provide useful strategies and data for comparative and functional genomics research. The interactive bioinformatics platform SilkMeta will benefit not only the silkworm but also the insect biology communities.

A monoclonal antibody targeting spore wall protein 1 inhibits the proliferation of Nosema bombycis in Bombyx mori

IMPORTANCE

There are a few reports on the resistance of microsporidia, including Nosema bombycis. Here, the alkali-soluble germination proteins of N. bombycis were used as immunogens to prepare a monoclonal antibody, and its single-chain variable fragments effectively blocked microsporidia infection. Our study has provided novel strategies for microsporidiosis control and demonstrated a useful method for the potential treatment of other microsporidia diseases.

Cas9-Mediated Gene Editing Using Receptor-Mediated Ovary Transduction of Cargo (ReMOT) Control in Bombyx mori

Lepidoptera is one of the most speciose insect orders, causing enormous damage to agricultural and forest crops. Although genome editing has been achieved in a few Lepidoptera for insect controls, most techniques are still limited. Here, by injecting female pupae of the Lepidoptera model species, Bombyx mori, gene editing was established using the Receptor-Mediated Ovary Transduction of Cargo (ReMOT) control technique. We identified a B. mori oocytes-targeting peptide ligand (BmOTP, a 29 aa of vitellogenin N-terminal of silkworms) with a highly conserved sequence in lepidopteran insects that could efficiently deliver mCherry into oocytes. When BmOTP was fused to CRISPR-associated protein 9 (Cas9) and the BmOTP-Cas9 ribonucleoprotein complex was injected into female pupae, heritable editing of the offspring was achieved in the silkworms. Compared with embryo microinjection, individual injection is more convenient and eliminates the challenge of injecting extremely small embryos. Our results will significantly facilitate the genetic manipulation of other lepidopteran insects, which is essential for advancing lepidopteran pest control.

Microsporidian Nosema bombycis hijacks host vitellogenin and restructures ovariole cells for transovarial transmission

Microsporidia are a group of obligate intracellular parasites that infect almost all animals, causing serious human diseases and major economic losses to the farming industry. Nosema bombycis is a typical microsporidium that infects multiple lepidopteran insects via fecal-oral and transovarial transmission (TOT); however, the underlying TOT processes and mechanisms remain unknown. Here, we characterized the TOT process and identified key factors enabling N. bombycis to invade the ovariole and oocyte of silkworm Bombyx mori. We found that the parasites commenced with TOT at the early pupal stage when ovarioles penetrated the ovary wall and were exposed to the hemolymph. Subsequently, the parasites in hemolymph and hemolymph cells firstly infiltrated the ovariole sheath, from where they invaded the oocyte via two routes: (I) infecting follicular cells, thereby penetrating oocytes after proliferation, and (II) infecting nurse cells, thus entering oocytes following replication. In follicle and nurse cells, the parasites restructured and built large vacuoles to deliver themselves into the oocyte. In the whole process, the parasites were coated with B. mori vitellogenin (BmVg) on their surfaces. To investigate the BmVg effects on TOT, we suppressed its expression and found a dramatic decrease of pathogen load in both ovarioles and eggs, suggesting that BmVg plays a crucial role in the TOT. Thereby, we identified the BmVg domains and parasite spore wall proteins (SWPs) mediating the interaction, and demonstrated that the von Willebrand domain (VWD) interacted with SWP12, SWP26 and SWP30, and the unknown function domain (DUF1943) bound with the SWP30. When disrupting these interactions, we found significant reductions of the pathogen load in both ovarioles and eggs, suggesting that the interplays between BmVg and SWPs were vital for the TOT. In conclusion, our study has elucidated key aspects about the microsporidian TOT and revealed the key factors for understanding the molecular mechanisms underlying this transmission.

Screening of the Pandemic Response Box identifies anti-microsporidia compounds

Microsporidia are fungal obligate intracellular pathogens, which infect most animals and cause microsporidiosis. Despite the serious threat that microsporidia pose to humans and agricultural animals, few drugs are available for the treatment and control of microsporidia. To identify novel inhibitors, we took advantage of the model organism Caenorhabditis elegans infected with its natural microsporidian Nematocida parisii. We used this system to screen the Pandemic Response Box, a collection of 400 diverse compounds with known antimicrobial activity. After testing these compounds in a 96-well format at high (100 μM) and low (40 μM) concentrations, we identified four inhibitors that restored the ability of C. elegans to produce progeny in the presence of N. parisii. All four compounds reduced the pathogen load of both N. parisii and Pancytospora epiphaga, a C. elegans-infecting microsporidia related to human-infecting species. One of these compounds, a known inhibitor of a viral protease, MMV1006203, inhibited invasion and prevented the firing of spores. A bis-indole derivative, MMV1593539, decreased spore viability. An albendazole analog, MMV1782387, inhibited proliferation of N. parisii. We tested albendazole as well as 5 other analogs and observed that MMV1782387 was amongst the strongest inhibitors of N. parisii and displayed the least host toxicity. Our study further demonstrates the effectiveness of the C. elegans-N. parisii system for discovering microsporidia inhibitors and the compounds we identified provide potential scaffolds for anti-microsporidia drug development.

Hematoma-like dynamic hydrogelation through natural glycopeptide molecular recognition for infected bone fracture repair

Infected bone fractures remain a major clinical challenge for orthopedic surgeons. From a tissue regeneration perspective, biomaterial scaffolds with antibacterial and osteoinductive activities are highly desired, while advanced materials capable of mimicking the pathological microenvironment during the healing process of infected tissues remain an area deserving more research. Hematoma, the gel-like blood coagulum, plays an essential role in bone fracture repair because of its ability to serve as a dynamic and temporary scaffold with cytokines for both pathogen elimination and tissue healing. In light of this, we designed a dynamic hydrogel with hematoma-like antimicrobial or reparative performance for infected bone fracture repair in this study. The proposed dynamic hydrogel network was based on the reversible recognition of a natural glycopeptide antibiotic vancomycin (Van) and its target dipeptide D-Ala-D-Ala (AA), which could serve as a hematoma-like scaffold for obliterating bacteria in the fracture region and promoting bone repair by introducing an endogenous osteogenic peptide (OGP). In vivo experiments demonstrated that the hydrogel could rapidly eradicate bacteria, improve bone regeneration and restore the local inflammatory microenvironment. Together, findings from this study imply that the use of hematoma-like dynamic hydrogel could lead to a biomimetic revolution in surgical strategies against susceptible bone fractures.

A dynamic biointerface controls mussel adhesion

The mussel-adherent secreta interface reveals how nonliving material can be compatible with tissue.

First identification and coinfection detection of Enterocytozoon bieneusi, Encephalitozoon spp., Cryptosporidium spp. and Giardia duodenalis in diarrheic pigs in Southwest China

BACKGROUND

Enterocytozoon bieneusi, Encephalitozoon spp., Cryptosporidium spp., and Giardia duodenalis (G. intestinalis) are enteric pathogens that cause diarrhea in pigs. This study aimed to determine the prevalence of these enteric parasites and their coinfection with E. bieneusi in diarrheic pigs in Southwest China (Chongqing and Sichuan) using nested polymerase chain reaction (nPCR) based methods.

RESULTS

A total of 514 fecal samples were collected from diarrheic pigs from 14 pig farms in Chongqing (five farms) and Sichuan (nine farms) Provinces. The prevalence of Encephalitozoon spp., Cryptosporidium spp. and G. duodenalis was 16.14% (83/514), 0% (0/514), and 8.95% (46/514), respectively. Nested PCR revealed 305 mono-infections of E. bieneusi, six of E. cuniculi, two of E. hellem, and nine of G. duodenalis and 106 concurrent infections of E. bieneusi with the other enteric pathogens. No infections of E. intestinalis and Cryptosporidium species were detected. The highest coinfection was detected between E. bieneusi and E. cuniculi (10.5%, 54/514), followed by E. bieneusi and G. duodenalis (5.8%, 30/514) and E. bieneusi and E. hellem (2.9%, 15/514). E. bieneusi was the most frequently detected enteric pathogen, followed by E. cuniculi, G. duodenalis and E. hellem. There was a significant age-related difference in the prevalence of E. cuniculi in fattening pigs (χ2 = 15.266, df = 3, P = 0.002) and G. duodenalis in suckling pigs (χ2 = 11.92, df = 3, P = 0.008) compared with the other age groups. Sequence analysis of the ITS region of Encephalitozoon species showed two genotypes (II and III) for E. cuniculi and one (TURK1B) for E. hellem. Only G. duodenalis assemblage A was identified in all nested PCR-positive samples. E. bieneusi was found more often than other enteric pathogens.

CONCLUSIONS

This study showed that E. bieneusi, Encephalitozoon spp. [E. cuniculi and E. hellem] and G. duodenalis were common enteric parasites in diarrheic pigs in Chongqing and Sichuan Provinces. In case of both mono-infection and coinfection, E. bieneusi was the most common enteric pathogen in diarrheic pigs. Thus, it may be a significant cause of diarrhea in pigs. Precautions should be taken to prevent the spread of these enteric parasites.

Multivalency-enhanced enzyme inhibitors with biomolecule-responsive activity

This work reports a polymeric adenosine triphosphate (ATP)-responsive trypsin inhibitor. The polymeric inhibitor was rationally obtained by optimizing the benzamidine and phenylboronic acid monomers, which could synergistically bind with the phosphate and ribose groups in ATP. The ATP-responsive trypsin activity shows its potential as a therapeutic drug for cancer-targeting cell inhibition.

Characterization and fine mapping analysis of a major stable QTL qKnps-4A for kernel number per spike in wheat

KEY MESSAGE

A major stable QTL for kernel number per spike was narrowed down to a 2.19-Mb region containing two potential candidate genes, and its effects on yield-related traits were characterized. Kernel number per spike (KNPS) in wheat is a key yield component. Dissection and characterization of major stable quantitative trait loci (QTLs) for KNPS would be of considerable value for the genetic improvement of yield potential using molecular breeding technology. We had previously reported a major stable QTL controlling KNPS, qKnps-4A. In the current study, primary fine-mapping analysis, based on the primary mapping population, located qKnps-4A to an interval of approximately 6.8-Mb from 649.0 to 655.8 Mb on chromosome 4A refering to 'Kenong 9204' genome. Further fine-mapping analysis based on a secondary mapping population narrowed qKnps-4A to an approximately 2.19-Mb interval from 653.72 to 655.91 Mb. Transcriptome sequencing, gene function annotation analysis and homologous gene related reports showed that TraesKN4A01HG38570 and TraesKN4A01HG38590 were most likely to be candidate genes of qKnps-4A. Phenotypic analysis based on paired near-isogenic lines in the target region showed that qKnps-4A increased KNPS mainly by increasing the number of central florets per spike. We also evaluated the effects of qKnps-4A on other yield-related traits. Moreover, we dissected the QTL cluster of qKnps-4A and qTkw-4A and proved that the phenotypic effects were probably due to close linkage of two or more genes rather than pleiotropic effects of a single gene. This study provides molecular marker resource for wheat molecular breeding designed to improve yield potential, and lay the foundation for gene functional analysis of qKnps-4A.

Rational multivalency construction enables bactericidal effect amplification and dynamic biomaterial design

The multivalency of bioligands in living systems brings inspiration for not only the discovery of biological mechanisms but also the design of extracellular matrix (ECM)-mimicking biomaterials. However, designing controllable multivalency construction strategies is still challenging. Herein, we synthesized a series of well-defined multivalent antimicrobial peptide polymers (mAMPs) by clicking ligand molecules onto polymers prepared by reversible addition-fragmentation chain transfer polymerization. The multiple cationic ligands in the mAMPs could enhance the local disturbance of the anionic phospholipid layer of the bacterial membrane through multivalent binding, leading to amplification of the bactericidal effect. In addition to multivalency-enhanced antibacterial activity, mAMPs also enable multivalency-assisted hydrogel fabrication with an ECM-like dynamic structure. The resultant hydrogel with self-healing and injectable properties could be successfully employed as an antibacterial biomaterial scaffold to treat infected skin wounds. The multivalency construction strategy presented in this work provides new ideas for the biomimetic design of highly active and dynamic biomaterials for tissue repair and regeneration.

Kartogenin-enhanced dynamic hydrogel ameliorates intervertebral disc degeneration via restoration of local redox homeostasis

INTRODUCTION

Over-activation of oxidative stress due to impaired antioxidant functions in nucleus pulpous (NP) has been identified as a key factor contributing to intervertebral disc degeneration (IVDD). While Kartogenin (KGN) has previously demonstrated antioxidant properties on articular cartilage against osteoarthritis, its effects on NP degeneration have yet to be fully understood.

OBJECTIVES

This study aimed to investigate the protective effects of KGN on nucleus pulpous cells (NPCs) against an inflammatory environment induced by interleukin (IL)-1β, as well as to explore the therapeutic potential of KGN-enhanced dynamic hydrogel in preventing IVDD.

METHODS

NPCs were isolated from rat caudal IVDs and subjected to treatment with KGN at varying concentrations (ranging from 0.01 to 1 ​μM) in the presence of IL-1β. The expression of extracellular matrix (ECM) anabolism markers was quantitatively assessed at both the mRNA and protein levels. Additionally, intracellular reactive oxygen species and antioxidant enzyme expression were evaluated, along with the role of nuclear factor erythroid 2-related factor 2 (NRF2). Based on these findings, a dynamic self-healing hydrogel loaded with KGN was developed through interconnecting networks. Subsequently, KGN-enhanced dynamic hydrogel was administered into rat caudal IVDs that had undergone puncture injury, followed by radiographic analysis and immunohistochemical staining to evaluate the therapeutic efficacy.

RESULTS

In vitro treatments utilizing KGN were observed to maintain ECM synthesis and inhibit catabolic activities in IL-1β-stimulated NPCs. The mechanism behind this protective effect of KGN on NPCs was found to involve the asctivation of NRF2 and downstream antioxidant enzymes, including glutathione peroxidase 1 and heme oxygenase 1. This was further supported by the loss of both antioxidant and anabolic effects upon pharmacological inhibition of NRF2. Furthermore, a self-healing hydrogel was developed and loaded with KGN to achieve localized and sustained release of the compound. The injection of KGN-enhanced hydrogel effectively ameliorated the degradation of NP ECM and mitigated inflammation in a rat model of puncture-induced IVDD.

CONCLUSIONS

Our results indicate that KGN exhibits potential as a therapeutic agent for NP degeneration, and that KGN-enhanced dynamic hydrogel represents a novel approach for treating IVDD by restoring redox homeostasis in NP.The translational potential of this article: The dysregulation of oxidant and antioxidant balance has been shown to impede the repair and regeneration of NP, thereby hastening the progression of IVDD following injury. The present investigation has demonstrated that the sustained release of KGN promotes the synthesis of ECM in vitro and mitigates the progression of IVDD in vivo by restoring redox equilibrium, thereby presenting a novel therapeutic candidate based on the antioxidant properties of KGN for the treatment of IVDD.

The microsporidian polar tube: origin, structure, composition, function, and application

Microsporidia are a class of obligate intracellular parasitic unicellular eukaryotes that infect a variety of hosts, even including humans. Although different species of microsporidia differ in host range and specificity, they all share a similar infection organelle, the polar tube, which is also defined as the polar filament in mature spores. In response to the appropriate environmental stimulation, the spore germinates with the polar filament everted, forming a hollow polar tube, and then the infectious cargo is transported into host cells via the polar tube. Hence, the polar tube plays a key role in microsporidian infection. Here, we review the origin, structure, composition, function, and application of the microsporidian polar tube, focusing on the origin of the polar filament, the structural differences between the polar filament and polar tube, and the characteristics of polar tube proteins. Comparing the three-dimensional structure of PTP6 homologous proteins provides new insight for the screening of additional novel polar tube proteins with low sequence similarity in microsporidia. In addition, the interaction of the polar tube with the spore wall and the host are summarized to better understand the infection mechanism of microsporidia. Due to the specificity of polar tube proteins, they are also used as the target in the diagnosis and prevention of microsporidiosis. With the present findings, we propose a future study on the polar tube of microsporidia.

Non-coding RNAs identification and regulatory networks in pathogen-host interaction in the microsporidia congenital infection

BACKGROUND

The interaction networks between coding and non-coding RNAs (ncRNAs) including long non-coding RNA (lncRNA), covalently closed circular RNA (circRNA) and miRNA are significant to elucidate molecular processes of biological activities and interactions between host and pathogen. Congenital infection caused by vertical transmission of microsporidia N. bombycis can result in severe economic losses in the silkworm-feeding industry. However, little is known about ncRNAs that take place in the microsporidia congenital infection. Here we conducted whole-transcriptome RNA-Seq analyses to identify ncRNAs and regulatory networks for both N. bombycis and host including silkworm embryos and larvae during the microsporidia congenital infection.

RESULTS

A total of 4,171 mRNAs, 403 lncRNA, 62 circRNAs, and 284 miRNAs encoded by N. bombycis were identified, among which some differentially expressed genes formed cross-talk and are involved in N. bombycis proliferation and infection. For instance, a lncRNA/circRNA competing endogenous RNA (ceRNA) network including 18 lncRNAs, one circRNA, and 20 miRNAs was constructed to describe 14 key parasites genes regulation, such as polar tube protein 3 (PTP3), ricin-B-lectin, spore wall protein 4 (SWP4), and heat shock protein 90 (HSP90). Regarding host silkworm upon N. bombycis congenital infection, a total of 14,889 mRNAs, 3,038 lncRNAs, 19,039 circRNAs, and 3,413 miRNAs were predicted based on silkworm genome with many differentially expressed coding and non-coding genes during distinct developmental stages. Different species of RNAs form interacting network to modulate silkworm biological processes, such as growth, metamorphosis and immune responses. Furthermore, a lncRNA/circRNA ceRNA network consisting of 140 lncRNAs, five circRNA, and seven miRNAs are constructed hypothetically to describe eight key host genes regulation, such as Toll-6, Serpin-6, inducible nitric oxide synthase (iNOS) and Caspase-8. Notably, cross-species analyses indicate that parasite and host miRNAs play a vital role in pathogen-host interaction in the microsporidia congenital infection.

CONCLUSION

This is the first comprehensive pan-transcriptome study inclusive of both N. bombycis and its host silkworm with a specific focus on the microsporidia congenital infection, and show that ncRNA-mediated regulation plays a vital role in the microsporidia congenital infection, which provides a new insight into understanding the basic biology of microsporidia and pathogen-host interaction.