HMGB1: LPS Delivery Vehicle for Caspase-11-Mediated Pyroptosis.

Recognition of cytoplasmic lipopolysaccharide (LPS) by caspase-11 leads to pyroptosis and secretion of inflammatory mediators. In this issue of Immunity, Deng et al. (2018) report that high-mobility group box 1 (HMGB1) secreted by hepatocytes delivers extracellular LPS into the cytoplasm and mediates pyroptosis.

Reconstruction of LPS Transfer Cascade Reveals Structural Determinants within LBP, CD14, and TLR4-MD2 for Efficient LPS Recognition and Transfer.

Lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria, binds Toll-like receptor 4 (TLR4)-MD2 complex and activates innate immune responses. LPS transfer to TLR4-MD2 is catalyzed by both LPS binding protein (LBP) and CD14. To define the sequential molecular interactions underlying this transfer, we reconstituted in vitro the entire LPS transfer process from LPS micelles to TLR4-MD2. Using electron microscopy and single-molecule approaches, we characterized the dynamic intermediate complexes for LPS transfer: LBP-LPS micelles, CD14-LBP-LPS micelle, and CD14-LPS-TLR4-MD2 complex. A single LBP molecule bound longitudinally to LPS micelles catalyzed multi-rounds of LPS transfer to CD14s that rapidly dissociated from LPB-LPS complex upon LPS transfer via electrostatic interactions. Subsequently, the single LPS molecule bound to CD14 was transferred to TLR4-MD2 in a TLR4-dependent manner. The definition of the structural determinants of the LPS transfer cascade to TLR4 may enable the development of targeted therapeutics for intervention in LPS-induced sepsis.

[Analysis of Short-Term Results after Introduction of Robotic Gastrectomy for Gastric Cancer at Our Hospital].

BACKGROUND: Robotic gastrectomy(RG)for gastric cancer(GC)has been covered by health insurance since 2018. In this study, we examined the results of RG for GC at our hospital during the initial period of its introduction. MATERIALS AND METHOD: From August 2022 to May 2023, we retrospectively examined the surgical outcomes and short-term postoperative outcomes of the first 9 patients who underwent RG for GC at our hospital. RESULTS: The median patient age was 77(67-82) years, gender was 4 males and 5 females, and distal gastrectomy was performed in all patients. The median operative time was 410(323-486)min, blood loss was 5(1-140)mL, postoperative hospital stay was less than 9 days in all patients, and there was no conversion to laparoscopic or open surgery. There were no postoperative complications of Clavien-Dindo Grade Ⅱ or above. CONCLUSION: In this study, RG for GC was performed safely without intraoperative or postoperative complications.

Molecular basis for SMC rod formation and its dissolution upon DNA binding.

SMC condensin complexes are central modulators of chromosome superstructure in all branches of life. Their SMC subunits form a long intramolecular coiled coil, which connects a constitutive "hinge" dimerization domain with an ATP-regulated "head" dimerization module. Here, we address the structural arrangement of the long coiled coils in SMC complexes. We unequivocally show that prokaryotic Smc-ScpAB, eukaryotic condensin, and possibly also cohesin form rod-like structures, with their coiled coils being closely juxtaposed and accurately anchored to the hinge. Upon ATP-induced binding of DNA to the hinge, however, Smc switches to a more open configuration. Our data suggest that a long-distance structural transition is transmitted from the Smc head domains to regulate Smc-ScpAB's association with DNA. These findings uncover a conserved architectural theme in SMC complexes, provide a mechanistic basis for Smc's dynamic engagement with chromosomes, and offer a molecular explanation for defects in Cornelia de Lange syndrome.

[A Case of Rectal Neuroendocrine Carcinoma with Iris Metastasis].

A 62-year-old man with anal pain was diagnosed with rectal neuroendocrine carcinoma. There were multiple metastases in the liver, lung, paraaortic lymph node, and bone of the patient. After performing a diverting colostomy, irinotecan and cisplatin were administered. Partial response was obtained after 2 courses, and anal pain improved. However, after 8 courses, multiple skin metastases were found on his back. At the same time, the patient also complained of redness, pain, and impaired vision in the right eye. Iris metastasis was diagnosed clinically by ophthalmologic examination and with contrast- enhanced MRI. Iris metastasis was treated with 5 doses of 4 Gy irradiation, ameliorating the eye symptoms. The patient died of the original disease 13 months after the initial diagnosis; however, multidisciplinary treatment appeared effective for palliating cancer symptoms.

[A Rare Case of Advanced Gastric Cancer with Duodenal Intramural Metastasis].

Here we report the case of a patient with advanced gastric cancer who presented with duodenal intramural metastasis based on the pathological results after surgery. The patient was 78-year-old female, who was referred to our department for further evaluation and treatment of upper abdominal pain. An upper gastrointestinal series demonstrated a tumor occupying the lesser curvature of the gastric body. Biopsy specimens from the tumor demonstrated moderately to poorly differentiated adenocarcinoma. A computed tomography scan showed thickening of the gastric wall and swelling of the regional lymph nodes. The patient underwent distal gastrectomy and D2 lymph node dissection for gastric cancer. A histopathological examination disclosed that the gastric tumor was poorly differentiated adenocarcinoma with severe lymphatic permeation and also demonstrated the other poorly differentiated adenocarcinoma occupying the part of the muscularis propria layer of the duodenum. The gastric tumor was not contiguous with the duodenal tumor, and the duodenal cancer cells had the same pathological characteristics as the primary gastric cancer cells; therefore, we diagnosed the duodenal tumor as an intramural metastasis from gastric cancer. The patient's disease was staged as pT4aN3bM1, Stage Ⅳ according to the TNM classification. We report this rare case along with a discussion of the literature.

[A Case of Sigmoid Rectal Cancer with a Vesicoconstrictor Fistula Curatively Resected after Neoadjuvant Chemotherapy].

A 50-year-old man presented with fecaluria and was diagnosed with sigmoid colon cancer with a colovesical fistula. Total bladder resection was determined to be necessary for curative resection at the time of diagnosis. In anticipation of bladder preservation, 6 courses of mFOLFOX6 plus panitumumab were administered after transverse colostomy, resulting in marked tumor regression and a decision to proceed with surgery. The patient underwent robotic-assisted low anterior resection of the rectum and partial cystectomy, which yielded pathological radical treatment. We report a case of sigmoid colon cancer with a colovesical fistula complicated by bladder invasion, in which preoperative chemotherapy was effective and total cystectomy was avoided, allowing bladder preservation.

Structural basis of the fanconi anemia-associated mutations within the FANCA and FANCG complex.

Monoubiquitination of the Fanconi anemia complementation group D2 (FANCD2) protein by the FA core ubiquitin ligase complex is the central event in the FA pathway. FANCA and FANCG play major roles in the nuclear localization of the FA core complex. Mutations of these two genes are the most frequently observed genetic alterations in FA patients, and most point mutations in FANCA are clustered in the C-terminal domain (CTD). To understand the basis of the FA-associated FANCA mutations, we determined the cryo-electron microscopy (EM) structures of Xenopus laevis FANCA alone at 3.35 Å and 3.46 Å resolution and two distinct FANCA-FANCG complexes at 4.59 and 4.84 Å resolution, respectively. The FANCA CTD adopts an arc-shaped solenoid structure that forms a pseudo-symmetric dimer through its outer surface. FA- and cancer-associated point mutations are widely distributed over the CTD. The two different complex structures capture independent interactions of FANCG with either FANCA C-terminal HEAT repeats, or the N-terminal region. We show that mutations that disturb either of these two interactions prevent the nuclear localization of FANCA, thereby leading to an FA pathway defect. The structure provides insights into the function of FANCA CTD, and provides a framework for understanding FA- and cancer-associated mutations.

A Cryogen-Free 25-T REBCO Magnet with the Extreme-No-Insulation Winding Technique.

We present the operation result of a cryogen-free 23.5 T/φ12.5 mm-cold-bore magnet prototype composed of a stack of 12 no-insulation (NI) REBCO single pancake coils-ten middle coils of 6-mm wide and two end coils of 8-mm wide tape-forming 6 double pancake (DP) coils with inner joints. Each coil was wound with the tape having only 1-µm-thick copper layer on each side to overcome the conductor thickness uniformity issue and enhance the mechanical strength within the winding, and then, additional electrical shunting by thin layers of solder was applied on the top and bottom surfaces of each DP coil for effective cooling and quench protection-called extreme-NI winding technique. With this small prototype magnet towards a benchtop 1-GHz NMR, we validate our coil design that include conductor performance, screening-current-induced field and stresses, and conduction-cooling cryogenics. Included in the paper are: 1) conductor issues and our counterproposal in winding; 2) screening-current reduction method; 3) design and manufacture summary of the magnet; and 4) operating test results of the magnet up to 25 Tesla.

Administration Method of Adjuvant Tegafur-Uracil and Leucovorin Calcium in Patients with Resected Colorectal Cancer: A Phase III Study.

LESSONS LEARNED: The 3-year disease-free survival rate of the twice-daily regimen was not inferior to that of the conventional three-times-daily regimen, and the twice-daily regimen did not lead to an increase in adverse events. The effectiveness of the twice-daily regimen highlights an increased number of treatment options for patients. This will facilitate personalized medicine, particularly for elderly or frail patients who may experience more severe side effects from the combination therapy. BACKGROUND: Tegafur-uracil (UFT)/leucovorin calcium (LV) is an adjuvant chemotherapy treatment for colorectal cancer. We conducted a multicenter randomized trial to assess the noninferiority of a twice-daily compared with a three-times-daily UFT/LV regimen for stage II/III colorectal cancer in an adjuvant setting. METHODS: Patients were randomly assigned to group A (three doses of UFT [300 mg/m2 per day]/LV [75 mg per day]) or B (two doses of UFT [300 mg/m2 per day]/LV [50 mg per day]). The primary endpoint was 3-year disease-free survival. RESULTS: In total, 386 patients were enrolled between July 28, 2011, and September 27, 2013. The 3-year disease-free survival rates of group A (n = 194) and B (n = 192) were 79.4% and 81.4% (95% confidence interval, 72.6-84.4-74.5-85.9), respectively. The most common grade 3/4 adverse events in group A and B were diarrhea (3.9% vs. 7.3%), neutropenia (2.9% vs. 1.6%), increase in aspartate aminotransferase (4.0% vs. 3.9%), increase in alanine aminotransferase (6.2% vs. 6.8%), nausea (1.7% vs. 3.4%), and fatigue (1.1% vs. 2.3%). CONCLUSION: Group B outcomes were not inferior to group A outcomes, and adverse events did not increase.

ClpL is a functionally active tetradecameric AAA+ chaperone, distinct from hexameric/dodecameric ones.

AAA+ (ATPases associated with diverse cellular activities) chaperones are involved in a plethora of cellular activities to ensure protein homeostasis. The function of AAA+ chaperones is mostly modulated by their hexameric/dodecameric quaternary structures. Here we report the structural and biochemical characterizations of a tetradecameric AAA+ chaperone, ClpL from Streptococcus pneumoniae. ClpL exists as a tetradecamer in solution in the presence of ATP. The cryo-EM structure of ClpL at 4.5 Å resolution reveals a striking tetradecameric arrangement. Solution structures of ClpL derived from small-angle X-ray scattering data suggest that the tetradecameric ClpL could assume a spiral conformation found in active hexameric/dodecameric AAA+ chaperone structures. Vertical positioning of the middle domain accounts for the head-to-head arrangement of two heptameric rings. Biochemical activity assays with site-directed mutagenesis confirmed the critical roles of residues both in the integrity of the tetradecameric arrangement and activities of ClpL. Non-conserved Q321 and R670 are crucial in the heptameric ring assembly of ClpL. These results establish that ClpL is a functionally active tetradecamer, clearly distinct from hexameric/dodecameric AAA+ chaperones.

High-yield synthesis and purification of recombinant human GABA transaminase for high-throughput screening assays.

Many studies have focussed on modulating the activity of γ-aminobutyric acid transaminase (GABA-T), a GABA-catabolizing enzyme, for treating neurological diseases, such as epilepsy and drug addiction. Nevertheless, human GABA-T synthesis and purification have not been established. Thus, biochemical and drug design studies on GABA-T have been performed by using porcine GABA-T mostly and even bacterial GABA-T. Here we report an optimised protocol for overexpression of 6xHis-tagged human GABA-T in human cells followed by a two-step protein purification. Then, we established an optimised human GABA-T (0.5 U/mg) activity assay. Finally, we compared the difference between human and bacterial GABA-T in sensitivity to two irreversible GABA-T inhibitors, gabaculine and vigabatrin. Human GABA-T in homodimeric form showed 70-fold higher sensitivity to vigabatrin than bacterial GABA-T in multimeric form, indicating the importance of using human GABA-T. In summary, our newly developed protocol can be an important first step in developing more effective human GABA-T modulators.

Coiled-coil structure-dependent interactions between polyQ proteins and Foxo lead to dendrite pathology and behavioral defects.

Neurodegenerative disorders, such as Huntington's diseases and spinocerebellar ataxias (SCAs), are driven by proteins with expanded polyglutamine (polyQ) tracts. Recently, coiled-coil structures in polyQ regions of such proteins were shown to facilitate aggregate formation and ultimately lead to cell death. However, the molecular mechanism linking these structural domains to neuronal toxicity of polyQ proteins remains elusive. Here, we demonstrate that coiled-coil structures in the Q repeat region of SCA type 3 (SCA3) polyQ proteins confer protein toxicity in Drosophila neurons. To functionally characterize coiled-coil structures in the Q repeat regions, we generated three structural variants of SCA3 polyQ proteins: (i) MJDtr-76Q, containing both α-helical coiled-coil and ß-sheet hairpin structures in the Q repeat region; (ii) MJDtr-70Q_cc0, possessing only α-helical coiled-coil structures due to the incorporation of ß-sheet-breaking residues (Q-to-N or Q-to-E mutations); and (iii) MJDtr-70Q_pQp, with no secondary structure due to the introduced proline residues (Q-to-P mutations). Through comparative analysis of these variants, we found that coiled-coil structures facilitated nuclear localization of SCA3 polyQ proteins and induced dendrite defects in Drosophila dendritic arborization neurons. Furthermore, genetic and functional screening identified the transcription factor Foxo as a target of polyQ proteins, and coiled-coil-mediated interactions of Foxo and polyQ proteins in the nucleus resulted in the observed dendrite and behavioral defects in Drosophila These results demonstrate that coiled-coil structures of polyQ proteins are crucial for their neuronal toxicity, which is conferred through coiled-coil to coiled-coil interactions with the nuclear targets of these proteins.

[Capecitabine and Oxaliplatin(CAPOX)plus Bevacizumab as Second-Line Chemotherapy for Metastatic Colorectal Cancer].

OBJECTIVE: To evaluate the efficacy and safety of CAPOX plus bevacizumab as second-line chemotherapy for metastatic colorectal cancer. METHODS: In this multicenter phase Ⅱ study, the planned number of patients was 48, but owing to poor case accumulation, registration was discontinued for 20 patients. The primary endpoint was the response rate(RR). Secondary endpoints were progression-free survival(PFS), overall survival(OS), disease control rate(DCR), and safety. RESULTS: First-line treatment was combined with irinotecan in 14 cases and bevacizumab in 12 cases. The median number of second- line treatment courses was 7, and the median treatment period was 203 days. The reason for discontinuation of treatment was disease progression in 13 cases, adverse events in 4 cases, and other reasons in 3 cases. The best response was PR in 5 cases, SD in 8 cases, and NE in 4 cases. The RR was 25%, and the DCR was 65%. The median PFS was 7.2 months, and the median OS was 18.6 months. Grade≥3 adverse events were neutropenia in 3 cases and diarrhea and peripheral neuropathy in 2 cases each. There were no treatment-related deaths. CONCLUSION: CAPOX plus bevacizumab was a safe and effective second-line treatment option for metastatic colorectal cancer.

Structure-based glycoengineering of interferon lambda 4 enhances its productivity and anti-viral potency.

Interferon lambda 4 (IFNλ4) has been recently known and studied for its role in hepatitis C virus (HCV) infection, but its clinical potential is significantly hampered due to its poor expression in vitro. Our study reports the successful production of IFNλ4 from a mammalian cell line through a glycoengineering and structure-based approach. We introduced de novo N-glycosylation of IFNλ4, guided by structural analysis, and produced IFNλ4 variants in Expi293F that displayed improved expression and potency. To preserve the structure and functionality of IFNλ4, the model structure of the IFNλ4 signaling complex was analyzed and the N-glycosylation candidate sites were selected. The receptor binding activity of engineered IFNλ4 variants and their receptor-mediated signaling pathway were similar to the E. coli version of IFNλ4 (eIFNλ4), while the antiviral activity and induction levels of interferon-stimulated gene (ISG) were all more robust in our variants. Our engineered IFNλ4 variants may be further developed for clinical applications and utilized in basic research to decipher the immunological roles of IFNλ4.

Metal-Mediated Protein Assembly Using a Genetically Incorporated Metal-Chelating Amino Acid.

Many natural proteins function in oligomeric forms, which are critical for their sophisticated functions. The construction of protein assemblies has great potential for biosensors, enzyme catalysis, and biomedical applications. In designing protein assemblies, a critical process is to create protein-protein interaction (PPI) networks at defined sites of a target protein. Although a few methods are available for this purpose, most of them are dependent on existing PPIs of natural proteins to some extent. In this report, a metal-chelating amino acid, 2,2'-bipyridylalanine (BPA), was genetically introduced into defined sites of a monomeric protein and used to form protein oligomers. Depending on the number of BPAs introduced into the protein and the species of metal ions (Ni2+ and Cu2+), dimers or oligomers with different oligomerization patterns were formed by complexation with a metal ion. Oligomer sizes could also be controlled by incorporating two BPAs at different locations with varied angles to the center of the protein. When three BPAs were introduced, the monomeric protein formed a large complex with Ni2+. In addition, when Cu2+ was used for complex formation with the protein containing two BPAs, a linear complex was formed. The method proposed in this report is technically simple and generally applicable to various proteins with interesting functions. Therefore, this method would be useful for the design and construction of functional protein assemblies.

Multivalent-Interaction-Driven Assembly of Discrete, Flexible, and Asymmetric Supramolecular Protein Nano-Prisms.

Current approaches to design monodisperse protein assemblies require rigid, tight, and symmetric interactions between oligomeric protein units. Herein, we introduce a new multivalent-interaction-driven assembly strategy that allows flexible, spaced, and asymmetric assembly between protein oligomers. We discovered that two polygonal protein oligomers (ranging from triangle to hexagon) dominantly form a discrete and stable two-layered protein prism nanostructure via multivalent interactions between fused binding pairs. We demonstrated that protein nano-prisms with long flexible peptide linkers (over 80 amino acids) between protein oligomer layers could be discretely formed. Oligomers with different structures could also be monodispersely assembled into two-layered but asymmetric protein nano-prisms. Furthermore, producing higher-order architectures with multiple oligomer layers, for example, 3-layered nano-prisms or nanotubes, was also feasible.

Reconfiguration of the proteasome during chaperone-mediated assembly.

The proteasomal ATPase ring, comprising Rpt1-Rpt6, associates with the heptameric α-ring of the proteasome core particle (CP) in the mature proteasome, with the Rpt carboxy-terminal tails inserting into pockets of the α-ring. Rpt ring assembly is mediated by four chaperones, each binding a distinct Rpt subunit. Here we report that the base subassembly of the Saccharomyces cerevisiae proteasome, which includes the Rpt ring, forms a high-affinity complex with the CP. This complex is subject to active dissociation by the chaperones Hsm3, Nas6 and Rpn14. Chaperone-mediated dissociation was abrogated by a non-hydrolysable ATP analogue, indicating that chaperone action is coupled to nucleotide hydrolysis by the Rpt ring. Unexpectedly, synthetic Rpt tail peptides bound α-pockets with poor specificity, except for Rpt6, which uniquely bound the α2/α3-pocket. Although the Rpt6 tail is not visualized within an α-pocket in mature proteasomes, it inserts into the α2/α3-pocket in the base-CP complex and is important for complex formation. Thus, the Rpt-CP interface is reconfigured when the lid complex joins the nascent proteasome to form the mature holoenzyme.

Neuronal calcium channel α1 subunit interacts with AMPA receptor, increasing its cell surface localisation.

Voltage-activated Ca2+ channels (Cav) play critical roles in excitable cells including neurons. Unlike the well-defined roles of Cav2 for pre-synaptic neurotransmission, the post-synaptic function of Cav2 is unclear. Based on our previous study demonstrating the postsynaptic association of the Cav2 with the AMPA receptor (AMPA-R), in this study we sought to further analyse the Cav2-AMPA-R association. We used a step-by-step dissociation of partially purified native Cav2-AMPA-R complexes and co-immunoprecipitation of the Cav2-AMPA-R complexes expressed in HEK293T cells to demonstrate that the main subunit of Cav, α1, formed a complex with the AMPA-R without the auxiliary subunits ß, α2δ, γ2/3. The α1 subunit increased the cell-surface localisation of the AMPA-R, which could be a post-synaptic function of the Cav2.

PTPσ functions as a presynaptic receptor for the glypican-4/LRRTM4 complex and is essential for excitatory synaptic transmission.

Leukocyte common antigen-related receptor protein tyrosine phosphatases--comprising LAR, PTPδ, and PTPσ--are synaptic adhesion molecules that organize synapse development. Here, we identify glypican 4 (GPC-4) as a ligand for PTPσ. GPC-4 showed strong (nanomolar) affinity and heparan sulfate (HS)-dependent interaction with the Ig domains of PTPσ. PTPσ bound only to proteolytically cleaved GPC-4 and formed additional complex with leucine-rich repeat transmembrane protein 4 (LRRTM4) in rat brains. Moreover, single knockdown (KD) of PTPσ, but not LAR, in cultured neurons significantly reduced the synaptogenic activity of LRRTM4, a postsynaptic ligand of GPC-4, in heterologous synapse-formation assays. Finally, PTPσ KD dramatically decreased both the frequency and amplitude of excitatory synaptic transmission. This effect was reversed by wild-type PTPσ, but not by a HS-binding-defective PTPσ mutant. Our results collectively suggest that presynaptic PTPσ, together with GPC-4, acts in a HS-dependent manner to maintain excitatory synapse development and function.