Molecular basis of SAP05-mediated ubiquitin-independent proteasomal degradation of transcription factors.

SAP05, a secreted effector by the obligate parasitic bacteria phytoplasma, bridges host SPL and GATA transcription factors (TFs) to the 26 S proteasome subunit RPN10 for ubiquitination-independent degradation. Here, we report the crystal structures of SAP05 in complex with SPL5, GATA18 and RPN10, which provide detailed insights into the protein-protein interactions involving SAP05. SAP05 employs two opposing lobes with an acidic path and a hydrophobic path to contact TFs and RPN10, respectively. Our crystal structures, in conjunction with mutagenesis and degradation assays, reveal that SAP05 targets plant GATAs but not animal GATAs dependent on their direct salt-bridged electrostatic interactions. Additionally, SAP05 hijacks plant RPN10 but not animal RPN10 due to structural steric hindrance and the key hydrophobic interactions. This study provides valuable molecular-level information into the modulation of host proteins to prevent insect-borne diseases.

Rapidly achieving clinical remission in ulcerative colitis indicates better endoscopic and histological outcomes.

BACKGROUND: Clinical remission (CR) is the principal short-term treatment target in patients with ulcerative colitis (UC). However, whether rapidly achieving CR indicates better outcomes remains unclear. OBJECTIVES: We aimed to explore the associations between the timing of CR and therapeutic outcomes in UC. METHODS: This study included UC patients from the UNIFI trial. Week-2 CR and time to CR were the major variables of interest. Endoscopic remission (ER) at week 52 was the primary outcome. Multivariate logistic regression was performed to evaluate the association between variables and outcomes. RESULTS: Week-2 CR was associated with ER (aOR: 2.37 [95% CI: 1.28, 4.37], p = 0.006) and Histological remission (HR) (aOR: 2.87 [95% CI: 1.42, 5.72], p = 0.003) at week 52. Moreover, C-reactive protein (CRP) remission could further stratify patients without CR and predict week-52 outcomes. Patients with clinical activity + CRP remission (aOR: 0.49 [95% CI: 0.26, 0.93], p = 0.039) and clinical activity + CRP activity (aOR: 0.24 [95% CI: 0.11, 0.52], p < 0.001) had gradually decreased likelihood of achieving ER, when compared to those with CR. For time to CR, we found that the earlier to CR, the better endoscopic and histological outcomes patients would attain. Patients achieving CR at weeks 2, 4/8, 12/16 and >16 had gradually reduced proportions of ER (51.9% vs. 40.8% vs. 31.6% vs. 8.8%, p < 0.001) and HR (37.0% vs. 19.8% vs. 17.1% vs. 6.1%, p < 0.001) at week 52. Compared with week 2, achieving CR at weeks 4/8, 12/16 and >16 had 39%, 55% and 92% lower likelihoods of week-52 ER, respectively. CONCLUSIONS: Week-2 CR indicates better outcomes in UC patients receiving ustekinumab. Moreover, achieving CR more rapidly is associated with higher probability of ER and HR.

Current insights on the roles of gut microbiota in inflammatory bowel disease-associated extra-intestinal manifestations: pathophysiology and therapeutic targets.

Inflammatory bowel disease (IBD) is a chronic, recurrent inflammatory disease of the gastrointestinal tract. In addition to digestive symptoms, patients with IBD may also develop extra-intestinal manifestations (EIMs), the etiology of which remains undefined. The gut microbiota has been reported to exert a critical role in the pathogenesis of IBD, with a similar pattern of gut dysbiosis observed between patients with IBD and those with EIMs. Therefore, it is hypothesized that the gut microbiota is also involved in the pathogenesis of EIMs. The potential mechanisms are presented in this review, including: 1) impaired gut barrier: dysbiosis induces pore formation in the intestinal epithelium, and activates pattern recognition receptors to promote local inflammation; 2) microbial translocation: intestinal pathogens, antigens, and toxins translocate via the impaired gut barrier into extra-intestinal sites; 3) molecular mimicry: certain microbial antigens share similar epitopes with self-antigens, inducing inflammatory responses targeting extra-intestinal tissues; 4) microbiota-related metabolites: dysbiosis results in the dysregulation of microbiota-related metabolites, which could modulate the differentiation of lymphocytes and cytokine production; 5) immunocytes and cytokines: immunocytes are over-activated and pro-inflammatory cytokines are excessively released. Additionally, we summarize microbiota-related therapies, including probiotics, prebiotics, postbiotics, antibiotics, and fecal microbiota transplantation, to promote better clinical management of IBD-associated EIMs.

Near Net Forming Research for Fin-Typed LED Radiator.

Pure aluminum radiator is the best choice for heat dissipation of various LED products at present. Its forming methods include common extrusion, die casting, forging, etc. Compared with other forming technologies, the LED radiator formed by cold forging has good heat dissipation performance, but there are some disadvantages in the forming process, such as uneven deformation, large material consumption and low die life. The cold forging process of pure aluminum fin-typed LED radiator is analyzed by the finite element method. The calculation results show that equal fillet structure of concave die is improper, leading to serious uneven flow velocity distribution during aluminum forging, inconsistent fin length, and warpage tendency. The gradient fillet structure of concave die is adopted. Numerical simulation and production test show that the gradient fillet structure design can significantly reduce the uneven metal flow. The extruded fins have a uniform length, which is conducive to reducing subsequent machining and production cost.