Orchestration Of Photosynthesis-associated Gene Expression And Galactolipid Biosynthesis During Chloroplast Differentiation In Plants.

The chloroplast thylakoid membrane is composed of membrane lipids and photosynthetic protein complexes, and orchestration of thylakoid lipid biosynthesis and photosynthesis-associated protein accumulation is considered important for thylakoid development. Galactolipids consist of ~80% of the thylakoid lipids and their biosynthesis is fundamental for chloroplast development. We previously reported that the suppression of galactolipid biosynthesis decreased the expression of photosynthesis-associated nuclear- and plastid-encoded genes (PhANGs and PhAPGs). However, the mechanism for coordinative regulation between galactolipid biosynthesis in plastids and expression of PhANGs and PhAPGs remains largely unknown. To elucidate this mechanism, we investigated the gene expression patterns in galactolipid-deficient Arabidopsis seedlings during the deetiolation process. We found that galactolipids are crucial for inducing both the transcript accumulation of PhANGs and PhAPGs and the accumulation of plastid-encoded photosynthesis-associated proteins in developing chloroplasts. Genetic analysis indicates the contribution of GENOMES UNCOUPLED1 (GUN1)-mediated plastid-to-nucleus signaling pathway for PhANG regulation in response to galactolipid levels. Previous studies suggested that the accumulation of GUN1 reflects the state of protein homeostasis in plastids and alters the PhANG expression level. Thus we propose a model that galactolipid biosynthesis determines the protein homeostasis in plastids at the initial phase of deetiolation and optimizes the GUN1-dependent signaling to regulate the PhANG expression. This mechanism might contribute to orchestrating the biosynthesis of lipids and proteins for the biogenesis of functional chloroplasts in plants.

The balance between nuclear import and export of NLRC5 regulates MHC class I transactivation.

Major histocompatibility complex (MHC) class I molecules play an essential role in regulating the adaptive immune system by presenting antigens to CD8 T cells. CITA (MHC class I transactivator), also known as NLRC5 (NLR family, CARD domain-containing 5), regulates the expression of MHC class I and essential components involved in the MHC class I antigen presentation pathway. While the critical role of the nuclear distribution of NLRC5 in its transactivation activity has been known, the regulatory mechanism to determine the nuclear localization of NLRC5 remains poorly understood. In this study, a comprehensive analysis of all domains in NLRC5 revealed that the regulatory mechanisms for nuclear import and export of NLRC5 coexist and counterbalance each other. Moreover, GCN5 (general control non-repressed 5 protein), a member of HATs (histone acetyltransferases), was found to be a key player to retain NLRC5 in the nucleus, thereby contributing to the expression of MHC class I. Therefore, the balance between import and export of NLRC5 has emerged as an additional regulatory mechanism for MHC class I transactivation, which would be a potential therapeutic target for the treatment of cancer and virus-infected diseases.

Using hemoglobin vesicles to treat operative hemorrhagic shock after pneu- monectomy in dog models: an experimental study.

Hemoglobin vesicles (HbVs), considered as red blood cell substitutes, are liposomes encapsulating purified hemoglobin, with a phospholipid bilayer membrane (diameter: 250 nm; P50, 28 Torr). In this study, we aimed to investigate HbV function during hemorrhagic shock in lung resection and analyze the details of oxygen delivery. Left pneumonectomy was performed in dogs under mechanical ventilation, followed by rapid exsanguination of approximately 30% of the total circulating blood volume, which led to shock, reducing the mean arterial pressure (MAP) by approximately 60% of baseline. Subsequently, either 5% human serum albumin (HSA) or HbVs suspended in 5% HSA were infused for resuscitation. The MAP only recovered to 75% of baseline after HSA administration, but fully recovered (100%) after HbV administration, with significant differences between the groups (P < 0.005). Oxygen delivery was restored in the HbV group and was significantly higher than that in the HSA group (P < 0.0001). The infusion of HbVs dispersed in a 5% HSA solution compensated for the rapid loss of approximately 30% of the total circulating blood volume in a dog pneumonectomy model, even with impaired lung function. Thus, HbVs can be used for resuscitation from hemorrhagic shock during thoracic surgery.

Brucella-driven host N-glycome remodeling controls infection.

Many powerful methods have been employed to elucidate the global transcriptomic, proteomic, or metabolic responses to pathogen-infected host cells. However, the host glycome responses to bacterial infection remain largely unexplored, and hence, our understanding of the molecular mechanisms by which bacterial pathogens manipulate the host glycome to favor infection remains incomplete. Here, we address this gap by performing a systematic analysis of the host glycome during infection by the bacterial pathogen Brucella spp. that cause brucellosis. We discover, surprisingly, that a Brucella effector protein (EP) Rhg1 induces global reprogramming of the host cell N-glycome by interacting with components of the oligosaccharide transferase complex that controls N-linked protein glycosylation, and Rhg1 regulates Brucella replication and tissue colonization in a mouse model of brucellosis, demonstrating that Brucella exploits the EP Rhg1 to reprogram the host N-glycome and promote bacterial intracellular parasitism, thereby providing a paradigm for bacterial control of host cell infection.

Midlateral Approach Replantation of a Distal Phalanx Second Toe Amputation in a 4-Year-Old Child: A Case Report.

CASE: A 4-year-old girl patient presented with complete amputation of the second toe close to the distal interphalangeal joint. Replantation was performed using a novel midlateral approach. The procedure used the dorsal subcutaneous vein on the foot as a graft for the artery. Four months postoperatively, the toe healed without any complication. The patient reported pain-free physical exercise without limitations in daily activity. CONCLUSION: This report demonstrates that this approach has the potential to provide a safe and viable alternative for treating toe amputations and offers advantages such as simplified artery identification, straightforward anastomosis, and improved vein graft harvesting.

NLRC5/MHC class I transactivator: A key target for immune escape by SARS-CoV-2.

Antigen presentation to CD8+ T cells by MHC class I molecules is essential for host defense against viral infections. Various mechanisms have evolved in multiple viruses to escape immune surveillance and defense to support viral proliferation in host cells. Through in vitro SARS-CoV-2 infection studies and analysis of COVID-19 patient samples, we found that SARS-CoV-2 suppresses the induction of the MHC class I pathway by inhibiting the expression and function of NLRC5, a major transcriptional regulator of MHC class I genes. In this review, we discuss the molecular mechanisms for suppression of the MHC class I pathway and clinical implications for COVID-19.

Success Rates of Finger Revascularization and Replantation.

Background: Revascularization surgery has been reported to have a higher success rate than replantation due to sufficient venous return. However, in complex cases, success depends on a wide range of indications. This study aimed to investigate success rates in cohorts that included severe cases. Methods: This single-center, noninterventional, retrospective cohort study included 292 patients (349 digits) who underwent revascularization or replantation at our institution between January 2000 and December 2022. Sex, age, smoking history, comorbidities, affected digit, amputation level, complete or incomplete amputation, type of fracture and mechanism, artery diameter, needle, vein anastomosis in the revascularization subgroup, vein grafting, warm ischemic time, and outcomes were investigated and compared between the revascularization and replantation subgroups of the distal and proximal amputation groups. Results: In the distal amputation group, the arterial diameter in the revascularization subgroup was larger than that in the replantation subgroup (P < 0.05). In the proximal amputation group, the revascularization subgroup had a lower frequency of multiple amputations than the replantation subgroup (P < 0.05). Vein grafts were more frequently used in both revascularization subgroups than in the replantation subgroups (P < 0.05). However, the other injury severity indices were similar, and the success rates were not significantly different between the subgroups. Conclusions: The revascularization success rate was similar to that of replantation. Vein anastomosis or vein grafting to the veins should be advocated for revascularization in severe cases where skin bridges may not have sufficient venous return.

Results of an Adjustable Traction Method Using Surgical Gloves and K-Wires for the Treatment of Proximal Interphalangeal Joint Fracture Dislocation.

Purpose: This study aimed to evaluate an adjustable traction method using surgical gloves and Kirschner wires (K-wires) for proximal interphalangeal (PIP) fracture dislocations and examine the association between a reduction pin and range of motion (ROM), and between subluxation immediately after removal and ROM. Methods: Patients who underwent this surgical method for PIP joint dislocation fractures between 2003 and 2017 were included. We retrospectively investigated the postoperative results. We defined patients having surgery within 4 weeks after an injury as fresh cases and after 4 weeks as chronic cases. K-wires were inserted at the center of the proximal phalangeal head and the distal part of the middle phalanx to create a frame, and the finger of the surgical glove was used as a traction-force generator. We analyzed the association of ROM with each finger, age, presence of a reduction pin, and subluxation immediately after frame removal. Results: Overall, 37 fingers were included (27 acute and 10 chronic). The mean age of the participants was 40.0 years (range: 13-72 years). The mean follow-up period was 10.5 months (3-47 months). The final active ROM was -4.6°/94.6° (extension/flexion) for acute cases and -27.0°/73.5° for chronic ones. Active ROM was significantly better in patients with a reduction pin than in those without it. Subluxation immediately after frame removal was not associated with postoperative active ROM. Additionally, all PIP joints with subluxation that occurred immediately after frame removal achieved good joint congruity. Conclusions: The results of the adjustable traction method using surgical gloves and K-wires were satisfactory. Postoperative ROM did not decrease because of the additional reduction pin. Subluxation occurring immediately after frame removal did not affect the ROM, ultimately resulting in good joint congruity. Type of study/level of evidence: Therapeutic IV.

Targeted demethylation and activation of NLRC5 augment cancer immunogenicity through MHC class I.

Impaired expression of MHC (major histocompatibility complex) class I in cancers constitutes a major mechanism of immune evasion. It has been well documented that the low level of MHC class I is associated with poor prognosis and resistance to checkpoint blockade therapies. However, there is lmited approaches to specifically induce MHC class I to date. Here, we show an approach for robust and specific induction of MHC class I by targeting an MHC class I transactivator (CITA)/NLRC5, using a CRISPR/Cas9-based gene-specific system, designated TRED-I (Targeted reactivation and demethylation for MHC-I). The TRED-I system specifically recruits a demethylating enzyme and transcriptional activators on the NLRC5 promoter, driving increased MHC class I antigen presentation and accelerated CD8+ T cell activation. Introduction of the TRED-I system in an animal cancer model exhibited tumor-suppressive effects accompanied with increased infiltration and activation of CD8+ T cells. Moreover, this approach boosted the efficacy of checkpoint blockade therapy using anti-PD1 (programmed cell death protein) antibody. Therefore, targeting NLRC5 by this strategy provides an attractive therapeutic approach for cancer.

Biosynthesis of phosphatidylglycerol in photosynthetic organisms.

Phosphatidylglycerol (PG) is a unique phospholipid class with its indispensable role in photosynthesis and growth in land plants, algae, and cyanobacteria. PG is the only major phospholipid in the thylakoid membrane of cyanobacteria and plant chloroplasts and a main lipid component in photosynthetic protein-cofactor complexes such as photosystem I and photosystem II. In plants and algae, PG is also essential as a substrate for the biosynthesis of cardiolipin, which is a unique lipid present only in mitochondrial membranes and crucial for the functions of mitochondria. PG biosynthesis pathways in plants include three membranous organelles, plastids, mitochondria, and the endoplasmic reticulum in a complex manner. While the molecular biology underlying the role of PG in photosynthetic functions is well established, many enzymes responsible for the PG biosynthesis are only recently cloned and functionally characterized in the model plant species including Arabidopsis thaliana and Chlamydomonas reinhardtii and cyanobacteria such as Synechocystis sp. PCC 6803. The characterization of those enzymes helps understand not only the metabolic flow for PG production but also the crosstalk of biosynthesis pathways between PG and other lipids. This review aims to summarize recent advances in the understanding of the PG biosynthesis pathway and functions of involved enzymes.

Anionic lipids facilitate membrane development and protochlorophyllide biosynthesis in etioplasts.

Dark-germinated angiosperm seedlings develop chloroplast precursors called etioplasts in cotyledon cells. Etioplasts develop lattice membrane structures called prolamellar bodies (PLBs), where the chlorophyll intermediate protochlorophyllide (Pchlide) forms a ternary complex with NADPH and light-dependent NADPH:Pchlide oxidoreductase (LPOR). The lipid bilayers of etioplast membranes are mainly composed of galactolipids, which play important roles in membrane-associated processes in etioplasts. Although etioplast membranes also contain 2 anionic lipids, phosphatidylglycerol (PG) and sulfoquinovosyldiacylglycerol (SQDG), their roles are unknown. To determine the roles of PG and SQDG in etioplast development, we characterized etiolated Arabidopsis (Arabidopsis thaliana) mutants deficient in PG and SQDG biosynthesis. A partial deficiency in PG biosynthesis loosened the lattice structure of PLBs and impaired the insertion of Mg2+ into protoporphyrin IX, leading to a substantial decrease in Pchlide content. Although a complete lack of SQDG biosynthesis did not notably affect PLB formation and Pchlide biosynthesis, lack of SQDG in addition to partial PG deficiency strongly impaired these processes. These results suggested that PG is required for PLB formation and Pchlide biosynthesis, whereas SQDG plays an auxiliary role in these processes. Notably, PG deficiency and lack of SQDG oppositely affected the dynamics of LPOR complexes after photoconversion, suggesting different involvements of PG and SQDG in LPOR complex organization. Our data demonstrate pleiotropic roles of anionic lipids in etioplast development.

Ten-year clinical outcomes from a randomized trial comparing new-generation everolimus-eluting stent versus first-generation Sirolimus-eluting stent: Results from the RESET extended study.

BACKGROUND: New-generation drug-eluting stents (DES) achieved technological innovations and reported clinical advantages as compared with first-generation DES in clinical trials with 3-5 years follow-up. However, detailed clinical outcome data in very long-term follow-up is still scarce. OBJECTIVES: To evaluate 10-year clinical outcomes after first- and new-generation DES implantation. METHODS: In this extende follow-up study of the RESET, which is a largest randomized trial comparing everolimus-eluting stent (EES) with Sirolimus-eluting stent (SES), the study population consisted of 2892 patients from 84 centers. The primary efficacy and safety endpoints were target lesion revascularization (TLR) and a composite of death or myocardial infarction (MI), respectively. Complete 10-year follow-up was achieved in 87.9% of patients. RESULTS: Cumulative 10-year incidences of TLR and non-TLR were not significantly different between EES and SES (13.9% vs. 15.7%, Log-rank p = 0.20, and 33.4% vs. 31.3%, Log-rank p = 0.30). The cumulative 10-year incidence of death/MI was also not significantly different between the groups (32.5% vs. 34.4%, Log-rank p = 0.18). Cumulative 10-year incidence of definite stent thrombosis was numerically lower in EES than in SES (1.0% vs. 1.7%, Log-rank p = 0.16). The lower risk of EES relative to SES was significant for a composite endpoint of target lesion failure (TLF: 19.6% vs. 24.9%, Log-rank p = 0.001) and target vessel failure (TVF: 26.7% vs. 31.4%, Log-rank p = 0.006). CONCLUSION: During 10-year of follow-up, the risks for primary efficacy and safety endpoints were not significantly different between new-generation EES and first-generation SES, although EES compared with SES was associated with a lower risk for composite endpoints such as TLF and TVF.

Evolutionary implications from lipids in membrane bilayers and photosynthetic complexes in cyanobacteria and chloroplasts.

In biomembranes, lipids form bilayer structures that serve as the fluid matrix for membrane proteins and other hydrophobic compounds. Additionally, lipid molecules associate with membrane proteins and impact their structures and functions. In both cyanobacteria and the chloroplasts of plants and algae, the lipid bilayer of the thylakoid membrane consists of four distinct glycerolipid classes: monogalactosyldiacylglycerol, digalactosyldiacylglycerol, sulfoquinovosyldiacylglycerol, and phosphatidylglycerol. These lipids are also integral components of photosynthetic complexes such as photosystem II and photosystem I. The lipid-binding sites within the photosystems, as well as the lipid composition in the thylakoid membrane, are highly conserved between cyanobacteria and photosynthetic eukaryotes, and each lipid class has specific roles in oxygenic photosynthesis. This review aims to shed light on the potential evolutionary implications of lipid utilization in membrane lipid bilayers and photosynthetic complexes in oxygenic photosynthetic organisms.

FBXO11 constitutes a major negative regulator of MHC class II through ubiquitin-dependent proteasomal degradation of CIITA.

Major histocompatibility complex (MHC) class I and II molecules play critical roles in the activation and regulation of adaptive immunity through antigen presentation to CD8+ and CD4+ T cells, respectively. Strict regulation of MHC expression is critical for proper immune responses. CIITA (MHC class II transactivator), an NLR (nucleotide-binding domain, leucine-rich-repeat containing) protein, is a master regulator of MHC class II (MHC-II) gene transcription. Although it has been known that CIITA activity is regulated at the transcriptional and protein levels, the mechanism to determine CIITA protein level has not been elucidated. Here, we show that FBXO11 is a bona fide E3 ligase of CIITA and regulates CIITA protein level through ubiquitination-mediated degradation. A nonbiased proteomic approach for CIITA-binding protein identified FBXO11, a member of the Skp1-Cullin-1-F-box E3 ligase complex, as a binding partner of CIITA but not MHC class I transactivator, NLRC5. The cycloheximide chase assay showed that the half-life of CIITA is mainly regulated by FBXO11 via the ubiquitin-proteasome system. The expression of FBXO11 led to the reduced MHC-II at the promoter activity level, transcriptional level, and surface expression level through downregulation of CIITA. Moreover, human and mouse FBXO11-deficient cells display increased levels of MHC-II and related genes. In normal and cancer tissues, FBXO11 expression level is negatively correlated with MHC-II. Interestingly, the expression of FBXO11, along with CIITA, is associated with prognosis of cancer patients. Therefore, FBXO11 is a critical regulator to determine the level of MHC-II, and its expression may serve as a biomarker for cancer.

Accuracy of ZedView, the Software for Three-Dimensional Measurement and Preoperative Planning: A Basic Study.

Background and Objectives: In the field of orthopedic surgery, novel techniques of three-dimensional shape modeling using two-dimensional tomographic images are used for bone-shape measurements, preoperative planning in joint-replacement surgery, and postoperative evaluation. ZedView® (three-dimensional measurement instrument and preoperative-planning software) had previously been developed. Our group is also using ZedView® for preoperative planning and postoperative evaluation for more accurate implant placement and osteotomy. This study aimed to evaluate the measurement error in this software in comparison to a three-dimensional measuring instrument (3DMI) using human bones. Materials and Methods: The study was conducted using three bones from cadavers: the pelvic bone, femur, and tibia. Three markers were attached to each bone. Study 1: The bones with markers were fixed on the 3DMI. For each bone, the coordinates of the center point of the markers were measured, and the distances and angles between these three points were calculated and defined as "true values." Study 2: The posterior surface of the femur was placed face down on the 3DMI, and the distances from the table to the center of each marker were measured and defined as "true values." In each study, the same bone was imaged using computed tomography, measured with this software, and the measurement error from the corresponding "true values" was calculated. Results: Study 1: The mean diameter of the same marker using the 3DMI was 23.951 ± 0.055 mm. Comparisons between measurements using the 3DMI and this software revealed that the mean error in length was <0.3 mm, and the error in angle was <0.25°. Study 2: In the bones adjusted to the retrocondylar plane with the 3DMI and this software, the average error in the distance from the planes to each marker was 0.43 (0.32-0.58) mm. Conclusion: This surgical planning software could measure the distance and angle between the centers of the markers with high accuracy; therefore, this is very useful for pre- and postoperative evaluation.

Selection Bias in Avoiding Vein Graft in Replantation/Revascularization May Exist in Distal and Proximal Amputations, Respectively.

No difference in the success rate has been reported between the vein graft and non-vein graft groups in replantation/revascularization. However, this depends on a wide range of indications in difficult cases. This study aimed to investigate the selection bias in avoiding vein grafts. Methods: This is a single-center, noninterventional, retrospective cohort study comprising 229 patients (277 digits) who underwent replantation/revascularization between January 2000 and December 2020 at our institution. Sex, age, smoking history, comorbidities, affected side, level of amputation, complete or incomplete amputation, type of fracture and mechanism, diameter of the artery, needle, warm ischemic time, and results were investigated and compared between the subgroups with and without vein graft. Results were investigated between the subgroups with and without a vein graft in the distal and proximal groups. Results: In the distal group, the mean arterial diameter of the vein graft subgroup was larger than that of the non-vein graft subgroup [0.7 (0.1) mm and 0.6 (0.2) mm, respectively, P < 0.05]. In the proximal group, the vein graft subgroup had higher severity than the non-vein graft subgroup (comminuted fracture, 31.1% versus 13.4%; and avulsion or crush amputation, 57.8% versus 37.1%, respectively, P < 0.05). However, the success rate was not significantly different between the aforementioned subgroups. Conclusion: There was no significant difference between the vein graft and non-vein graft subgroups owing to the selection bias avoiding small arteries in the distal amputation and the absence of said bias in the proximal amputation.

Contractile pericarditis-like hemodynamics in dilated-phase hypertrophic cardiomyopathy with giant atrium.

A 47-year-old man with dilated-phase hypertrophic cardiomyopathy was admitted to the hospital with worsening heart failure. As the enlarged atrium caused a constrictive pericarditis-like hemodynamic condition, atrial wall resection and tricuspid valvuloplasty were performed. Postoperatively, pulmonary artery pressure rose due to increased preload; however, the rise in pulmonary artery wedge pressure was restrained, and the cardiac output significantly improved. When the pericardium is extremely stretched due to atrial enlargement, it can lead to an elevation of intrapericardial pressure, and both atrial volume reduction and tricuspid valve plasty could lead to increased compliance and contribute to hemodynamic improvement. Learning objective: Atrial wall resection for massive atrial enlargement and tricuspid annuloplasty in patients with diastolic-phase hypertrophic cardiomyopathy effectively relieves unstable hemodynamics.