SpiB regulates the expression of B-cell-related genes and increases the longevity of memory B cells

Generation of memory B cells is one of the key features of adaptive immunity as they respond rapidly to re-exposure to the antigen and generate functional antibodies. Although the functions of memory B cells are becoming clearer, the regulation of memory B cell generation and maintenance is still not well understood. Here we found that transcription factor SpiB is expressed in some germinal center (GC) B cells and memory B cells and participates in the maintenance of memory B cells. Overexpression and knockdown analyses revealed that SpiB suppresses plasma cell differentiation by suppressing the expression of Blimp1 while inducing Bach2 in the in-vitro-induced germinal center B (iGB) cell culture system, and that SpiB facilitates in-vivo appearance of memory-like B cells derived from the iGB cells. Further analysis in IgG1+ cell-specific SpiB conditional knockout (cKO) mice showed that function of SpiB is critical for the generation of late memory B cells but not early memory B cells or GC B cells. Gene expression analysis suggested that SpiB-dependent suppression of plasma cell differentiation is independent of the expression of Bach2. We further revealed that SpiB upregulates anti-apoptosis and autophagy genes to control the survival of memory B cells. These findings indicate the function of SpiB in the generation of long-lasting memory B cells to maintain humoral memory.

Delayed engagement of host defenses enables SARS-CoV-2 viremia and productive infection of distal organs in the hamster model of COVID-19

Clinical presentations that develop in response to infection result from interactions between the pathogen and host defenses. SARS-CoV-2, the etiologic agent of COVID-19, directly antagonizes these defenses, leading to delayed immune engagement in the lungs that materializes only as cells succumb to infection and are phagocytosed. Leveraging the golden hamster model of COVID-19, we sought to understand the dynamics between SARS-CoV-2 infection in the airways and the systemic host response that ensues. We found that early SARS-CoV-2 replication was largely confined to the respiratory tract and olfactory system and, to a lesser extent, the heart and gastrointestinal tract but generated a host antiviral response in every organ as a result of circulating type I and III interferons. Moreover, we showed that diminishing the response in the airways by immunosuppression or administration of SARS-CoV-2 intravenously resulted in decreased immune priming, viremia, and increased viral tropism, including productive infection of the liver, kidney, spleen, and brain. Last, we showed that productive infection of the airways was required for mounting an effective and system-wide antiviral response. Together, these data illustrate how COVID-19 can result in diverse clinical presentations in which disease outcomes can be a by-product of the speed and strength of immune engagement. These studies provide additional evidence for the mechanistic basis of the diverse clinical presentations of COVID-19 and highlight the ability of the respiratory tract to generate a systemic immune defense after pathogen recognition.

SARS-CoV-2 infection in hamsters and humans results in lasting and unique systemic perturbations after recovery

The host response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can result in prolonged pathologies collectively referred to as post-acute sequalae of COVID-19 (PASC) or long COVID. To better understand the mechanism underlying long COVID biology, we compared the short- and long-term systemic responses in the golden hamster after either SARS-CoV-2 or influenza A virus (IAV) infection. Results demonstrated that SARS-CoV-2 exceeded IAV in its capacity to cause permanent injury to the lung and kidney and uniquely affected the olfactory bulb (OB) and olfactory epithelium (OE). Despite a lack of detectable infectious virus, the OB and OE demonstrated myeloid and T cell activation, proinflammatory cytokine production, and an interferon response that correlated with behavioral changes extending a month after viral clearance. These sustained transcriptional changes could also be corroborated from tissue isolated from individuals who recovered from COVID-19. These data highlight a molecular mechanism for persistent COVID-19 symptomology and provide a small animal model to explore future therapeutics.

A diminished immune response underlies age-related SARS-CoV-2 pathologies

Morbidity and mortality in response to SARS-CoV-2 infection are significantly elevated in people of advanced age. To understand the underlying biology of this phenotype, we utilize the golden hamster model to compare how the innate and adaptive immune responses to SARS-CoV-2 infection differed between younger and older animals. We find that while both hamster cohorts showed similar virus kinetics in the lungs, the host response in older animals was dampened, with diminished tissue repair in the respiratory tract post-infection. Characterization of the adaptive immune response also revealed age-related differences, including fewer germinal center B cells in older hamsters, resulting in reduced potency of neutralizing antibodies. Moreover, older animals demonstrate elevated suppressor T cells and neutrophils in the respiratory tract, correlating with an increase in TGF-β and IL-17 induction. Together, these data support that diminished immunity is one of the underlying causes of age-related morbidity.

Immune memory from SARS-CoV-2 infection in hamsters provides variant-independent protection but still allows virus transmission

[Figure: see text].

Tox2 is required for the maintenance of GC TFH cells and the generation of memory TFH cells

Memory T follicular helper (TFH) cells play an essential role to induce secondary antibody response by providing help to memory and naïve B cells. Here, we show that the transcription factor Tox2 is vital for the maintenance of TFH cells in germinal centers (GCs) and the generation of memory TFH cells. High Tox2 expression was almost exclusive to GC TFH cells among human tonsillar and blood CD4+ T cell subsets. Tox2 overexpression maintained the expression of TFH-associated genes in T cell receptor–stimulated human GC TFH cells and inhibited their spontaneous conversion into TH1-like cells. Tox2-deficient mice displayed impaired secondary TFH cell expansion upon reimmunization with an antigen and upon secondary infection with a heterologous influenza virus. Collectively, our study shows that Tox2 is highly integrated into establishment of durable GC TFH cell responses and development of memory TFH cells in mice and humans.

Cardiomyocytes recruit monocytes upon SARS-CoV-2 infection by secreting CCL2

Heart injury has been reported in up to 20% of COVID-19 patients, yet the cause of myocardial histopathology remains unknown. Here, using an established in vivo hamster model, we demonstrate that SARS-CoV-2 can be detected in cardiomyocytes of infected animals. Furthermore, we found damaged cardiomyocytes in hamsters and COVID-19 autopsy samples. To explore the mechanism, we show that both human pluripotent stem cell-derived cardiomyocytes (hPSC-derived CMs) and adult cardiomyocytes (CMs) can be productively infected by SARS-CoV-2, leading to secretion of the monocyte chemoattractant cytokine CCL2 and subsequent monocyte recruitment. Increased CCL2 expression and monocyte infiltration was also observed in the hearts of infected hamsters. Although infected CMs suffer damage, we find that the presence of macrophages significantly reduces SARS-CoV-2-infected CMs. Overall, our study provides direct evidence that SARS-CoV-2 infects CMs in vivo and suggests a mechanism of immune cell infiltration and histopathology in heart tissues of COVID-19 patients.

A human-airway-on-a-chip for the rapid identification of candidate antiviral therapeutics and prophylactics

The rapid repurposing of antivirals is particularly pressing during pandemics. However, rapid assays for assessing candidate drugs typically involve in vitro screens and cell lines that do not recapitulate human physiology at the tissue and organ levels. Here we show that a microfluidic bronchial-airway-on-a-chip lined by highly differentiated human bronchial-airway epithelium and pulmonary endothelium can model viral infection, strain-dependent virulence, cytokine production and the recruitment of circulating immune cells. In airway chips infected with influenza A, the co-administration of nafamostat with oseltamivir doubled the treatment-time window for oseltamivir. In chips infected with pseudotyped severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), clinically relevant doses of the antimalarial drug amodiaquine inhibited infection but clinical doses of hydroxychloroquine and other antiviral drugs that inhibit the entry of pseudotyped SARS-CoV-2 in cell lines under static conditions did not. We also show that amodiaquine showed substantial prophylactic and therapeutic activities in hamsters challenged with native SARS-CoV-2. The human airway-on-a-chip may accelerate the identification of therapeutics and prophylactics with repurposing potential.

Leveraging the antiviral type I interferon system as a first line of defense against SARS-CoV-2 pathogenicity

The emergence and spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in significant global morbidity, mortality, and societal disruption. A better understanding of virus-host interactions may potentiate therapeutic insights toward limiting this infection. Here we investigated the dynamics of the systemic response to SARS-CoV-2 in hamsters by histological analysis and transcriptional profiling. Infection resulted in consistently high levels of virus in the upper and lower respiratory tracts and sporadic occurrence in other distal tissues. A longitudinal cohort revealed a wave of inflammation, including a type I interferon (IFN-I) response, that was evident in all tissues regardless of viral presence but was insufficient to prevent disease progression. Bolstering the antiviral response with intranasal administration of recombinant IFN-I reduced viral disease, prevented transmission, and lowered inflammation in vivo. This study defines the systemic host response to SARS-CoV-2 infection and supports use of intranasal IFN-I as an effective means of early treatment.

SARS-CoV-2 Infected Cardiomyocytes Recruit Monocytes by Secreting CCL2

Heart injury has been reported in up to 20% of COVID-19 patients, yet the cause of myocardial histopathology remains unknown. In order to study the cause of myocardial pathology in COVID-19 patients, we used a hamster model to determine whether following infection SARS-CoV-2, the causative agent of COVID-19, can be detected in heart tissues. Here, we clearly demonstrate that viral RNA and nucleocapsid protein is present in cardiomyocytes in the hearts of infected hamsters. Interestingly, functional cardiomyocyte associated gene expression was decreased in infected hamster hearts, corresponding to an increase in reactive oxygen species (ROS). This data using an animal model was further validated using autopsy heart samples of COVID-19 patients. Moreover, we show that both human pluripotent stem cell-derived cardiomyocytes (hPSC-derived CMs) and adult cardiomyocytes (CMs) can be infected by SARS-CoV-2 and that CCL2 is secreted upon SARS-CoV-2 infection, leading to monocyte recruitment. Increased CCL2 expression and macrophage infiltration was also observed in the hearts of infected hamsters. Using single cell RNA-seq, we also show that macrophages are able to decrease SARS-CoV-2 infection of CMs. Overall, our study provides direct evidence that SARS-CoV-2 infects CMs in vivo and proposes a mechanism of immune-cell infiltration and pathology in heart tissue of COVID-19 patients.

Topological charge transport by mobile dielectric-ferroelectric domain walls

The concept of topology has been widely applied in condensed matter physics, leading to the identification of peculiar electronic states on three-dimensional (3D) surfaces or 2D lines separating topologically distinctive regions. In the systems explored so far, the topological boundaries are built-in walls; thus, their motional degrees of freedom, which potentially bring about new paradigms, have been experimentally inaccessible. Here, working with a quasi-1D organic material with a charge-transfer instability, we show that mobile neutral-ionic (dielectric-ferroelectric) domain boundaries with topological charges carry strongly 1D-confined and anomalously large electrical conduction with an energy gap much smaller than the one-particle excitation gap. This consequence is further supported by nuclear magnetic resonance detection of spin solitons, which are required for steady current of topological charges. The present observation of topological charge transport may open a new channel for broad charge transport-related phenomena such as thermoelectric effects.

The quantity of CD40 signaling determines the differentiation of B cells into functionally distinct memory cell subsets

In mice, memory B (B_mem) cells can be divided into two subpopulations: CD80^hi B_mem cells, which preferentially differentiate into plasma cells; and CD80^lo B_mem cells, which become germinal center (GC) B cells during a recall response. We demonstrate that these distinct responses can be B-cell-intrinsic and essentially independent of B-cell receptor (BCR) isotypes. Furthermore, we find that the development of CD80^hi B_mem cells in the primary immune response requires follicular helper T cells, a relatively strong CD40 signal and a high-affinity BCR on B cells, whereas the development of CD80^lo B_mem cells does not. Quantitative differences in CD40 stimulation were enough to recapitulate the distinct B cell fate decisions in an in vitro culture system. The quantity of CD40 signaling appears to be translated into NF-κB activation, followed by BATF upregulation that promotes B_mem cell differentiation from GC B cells.

Evidence for solitonic spin excitations from a charge-lattice-coupled ferroelectric order

Topological defects have been explored in different fields ranging from condensed matter physics and particle physics to cosmology. In condensed matter, strong coupling between charge, spin, and lattice degrees of freedom brings about emergent excitations with topological characteristics at low energies. One-dimensional (1D) systems with degenerate dimerization patterns are typical stages for the generation of topological defects, dubbed "solitons"; for instance, charged solitons are responsible for high electrical conductivity in doped trans-polyacetylene. Here, we provide evidence based on a nuclear magnetic resonance (NMR) study for mobile spin solitons deconfined from a strongly charge-lattice-coupled spin-singlet ferroelectric order in a quasi-1D organic charge-transfer complex. The NMR spectral shift and relaxation rate associated with static and dynamic spin susceptibilities indicate that the ferroelectric order is violated by dilute solitonic spin excitations, which were further demonstrated to move diffusively by the frequency dependence of the relaxation rate. The traveling solitons revealed here may promise the emergence of anomalous electrical and thermal transport.

Potential Pathways Associated With Exaggerated T Follicular Helper Response in Human Autoimmune Diseases

Convincing lines of evidence in both mice and humans show that exaggerated T follicular helper (Tfh) responses is pathogenic in autoimmune diseases. However, the cause of exaggerated Tfh response in humans is still much less clear than in mouse models where genetic factors can be manipulated for in vivo testing. Nonetheless, recent advances in our understanding on the mechanisms of human Tfh differentiation and identification of multiple risk loci in genome-wide association studies have revealed several pathways potentially associated with exaggerated Tfh response in human autoimmune diseases. In this review, we will first briefly summarize the differentiation mechanisms of Tfh cells in humans. We describe the features of “Tfh-like” cells recently identified in inflamed tissues of human autoimmune diseases. Then we will discuss how risk loci identified in GWAS are potentially involved in exaggerated Tfh response in human autoimmune diseases.

Strong polarization switching with low-energy loss in hydrogen-bonded organic antiferroelectrics

The electric-field-induced phase transition from antipolar to polar structures is at the heart of antiferroelectricity. We demonstrate direct evidence of antiferroelectricity by applying a strong electric field to two antipolar crystals of squaric acid (SQA) and 5,5'-dimethyl-2,2'-bipyridinium chloranilate. The field-induced polarization of SQA is quite large and reasonably explained by the theoretically calculated polarization on the hydrogen-bonded sheet sublattice. The pseudo-tetragonal lattice of SQA permits unique switching topologies that produce two different ferroelectric phases of low and high polarizations. By tilting the applied field direction, the electrical switching mechanism can be attributed to a 90° rotation of the sheet polarization. From the viewpoint of applications, the strong polarization, high switching field, and quite slim hysteresis observed in the polarization versus electric field curve for SQA are advantageous for excellent-efficiency energy storage devices.

Shift current photovoltaic effect in a ferroelectric charge-transfer complex

Shift current is a steady-state photocurrent generated in non-centrosymmetric single crystals and has been considered to be one of the major origins of the bulk photovoltaic effect. The mechanism of this effect is the transfer of photogenerated charges by the shift of the wave functions, and its amplitude is closely related to the polarization of the electronic origin. Here, we report the photovoltaic effect in an organic molecular crystal tetrathiafulvalene-p-chloranil with a large ferroelectric polarization mostly induced by the intermolecular charge transfer. We observe a fairly large zero-bias photocurrent with visible-light irradiation and switching of the current direction by the reversal of the polarization. Furthermore, we reveal that the travel distance of photocarriers exceeds 200 μm. These results unveil distinct features of the shift current and the potential application of ferroelectric organic molecular compounds for novel optoelectric devices.The bulk photovoltaics refers to an effect whereby electrons move directionally in non-centrosymmetric crystals upon light radiation. Here, Nakamura et al. observe this effect in a ferroelectric organic charge-transfer complex, which shows large diffusion distance of photogenerated electrons over 200 µm.

Ultrafast Photoinduced Electric-Polarization Switching in a Hydrogen-Bonded Ferroelectric Crystal

Croconic acid crystals show proton displacive-type ferroelectricity with a large spontaneous polarization reaching 20  μC/cm^{2}, which originates from the strong coupling of proton and π-electron degrees of freedom. Such a coupling makes us expect a large polarization change by photoirradiations. Optical-pump second-harmonic-generation-probe experiments reveal that a photoexcited croconic-acid crystal loses the ferroelectricity substantially with a maximum quantum efficiency of more than 30 molecules per one absorbed photon. Based on density functional calculations, we theoretically discuss possible pathways toward the formation of a one-dimensional domain with polarization inversion and its recovery process to the ground state by referring to the dynamics of experimentally obtained polarization changes.

Novel PAX9 Mutations Cause Non-syndromic Tooth Agenesis

PAX9 is a transcription factor expressed in the tooth mesenchyme during tooth morphogenesis. In Pax9-null mice, tooth development is arrested at the bud stage. In humans, heterozygous mutations in PAX9 have been associated with non-syndromic tooth agenesis, predominantly in the molars. Here, we report 2 novel mutations in the paired domain of PAX9, a three-nucleotide deletion (73-75 delATC) and a missense mutation (C146T), in two unrelated Japanese patients with non-syndromic tooth agenesis. The individual with the 73-75del ATC mutation was missing all maxillary molars and mandibular second and third molars. The individual with the C146T mutation was missing the mandibular central incisors, maxillary second premolars, and first molars, along with all second and third molars. Both mutations affected amino acids that are highly conserved among different species and are critical for DNA binding. When both mutants were transfected to COS7 cells, nuclear localization of PAX9 proteins was not affected. However, reduced expression of the mutant proteins and almost no transcriptional activity of the target BMP4 gene were observed, suggesting haploinsufficiency of PAX9 as the cause of non-syndromic tooth agenesis.

Type 1 Pili Enhance the Invasion ofSalmonella braenderupandSalmonella typhimuriumto HeLa Cells

The relationship between type 1 pili-associated adhesion and invasion to HeLa cells by Salmonella braenderup and S. typhimurium was studied. When the clinical isolates of these strains were grown in L-broth, they showed both type 1 pili formation and mannose-sensitive adhesion to HeLa cells. On the other hand, the type 1 pili-defective mutants, which were obtained either by repeated subcultures on L-agar plates or by the transposon Tn1-insertion mutagenesis of the S. braenderup and S. typhimurium strains, concomitantly lost mannose-sensitive adhesion to HeLa cells. When the HeLa cells were incubated with Salmonella, the type 1 piliated strains invaded the HeLa cells with much higher infection rate than did the type 1 pili-defective strains. The invasion of type 1 piliated strains to HeLa cells was markedly inhibited in the presence of D-mannose. The infectivity of the strain, which lost type 1 pili but still had mannose-resistant adhesion, was slightly higher than that of the strains defective in both mannose-sensitive and mannose-resistant adhesion. These results suggested that type 1 pili have a role in enhancing the invasion of S. braenderup and S. typhimurium to HeLa cells.

Genome-Wide Gene Expression Profiling Revealed a Critical Role for GATA3 in the Maintenance of the Th2 Cell Identity

Functionally polarized CD4+ T helper (Th) cells such as Th1, Th2 and Th17 cells are central to the regulation of acquired immunity. However, the molecular mechanisms governing the maintenance of the polarized functions of Th cells remain unclear. GATA3, a master regulator of Th2 cell differentiation, initiates the expressions of Th2 cytokine genes and other Th2-specific genes. GATA3 also plays important roles in maintaining Th2 cell function and in continuous chromatin remodeling of Th2 cytokine gene loci. However, it is unclear whether continuous expression of GATA3 is required to maintain the expression of various other Th2-specific genes. In this report, genome-wide DNA gene expression profiling revealed that GATA3 expression is critical for the expression of a certain set of Th2-specific genes. We demonstrated that GATA3 dependency is reduced for some Th2-specific genes in fully developed Th2 cells compared to that observed in effector Th2 cells, whereas it is unchanged for other genes. Moreover, effects of a loss of GATA3 expression in Th2 cells on the expression of cytokine and cytokine receptor genes were examined in detail. A critical role of GATA3 in the regulation of Th2-specific gene expression is confirmed in in vivo generated antigen-specific memory Th2 cells. Therefore, GATA3 is required for the continuous expression of the majority of Th2-specific genes involved in maintaining the Th2 cell identity.

Advanced Glycation End Products (AGE)-Modified Proteins and Their Potential Relevance to Atherosclerosis

Modification of proteins by long-term incubation with glucose leads, through the formation of early products such as Schiff base and Amadori rearrangement products, to the formation of advanced glycation end products (AGE). AGE-modified proteins are characterized physicochemically by fluorescence, brown coloration, and intramolecular or intermolecular cross-linking. Biologically, they are specifically recognized by the AGE receptors of the cell surface membrane. Recent studies have provided evidence for the involvement of AGE proteins in atherosclerosis. First, in vitro experiments using Chinese hamster ovary cells overexpressing the macrophage scavenger receptor (MSR) and peritoneal macrophages from MSR-knockout mice demonstrated that MSR plays a major role as the AGE receptor in the endocytotic uptake of AGE by macrophages. Second, immunohistochemical studies using anti-AGE antibody and anti-MSR antibody revealed the presence of AGE proteins in human atherosclerotic lesions in arterial walls. Because MSR is closely associated with the formation of early atherosclerotic lesions, these results suggest a potential role played by AGE proteins or their interaction with MSR in the atherosclerotic process. (Trends Cardiovasc Med 1996;6:163-168).

Genome-wide analysis reveals unique regulation of transcription of Th2-specific genes by GATA3

Differentiation of naive CD4 T cells into Th2 cells is accompanied by chromatin remodeling and increased expression of a set of Th2-specific genes, including those encoding Th2 cytokines. IL-4-mediated STAT6 activation induces high levels of transcription of GATA3, a master regulator of Th2 cell differentiation, and enforced expression of GATA3 induces Th2 cytokine expression. However, it remains unclear whether the expression of other Th2-specific genes is induced directly by GATA3. A genome-wide unbiased chromatin immunoprecipitation assay coupled with massive parallel sequencing analysis revealed that GATA3 bound to 1279 genes selectively in Th2 cells, and 101 genes in both Th1 and Th2 cells. Simultaneously, we identified 26 highly Th2-specific STAT6-dependent inducible genes by DNA microarray analysis-based three-step selection processes, and among them 17 genes showed GATA3 binding. We assessed dependency on GATA3 for the transcription of these 26 Th2-specific genes, and 10 genes showed increased transcription in a GATA3-dependent manner, whereas 16 genes showed no significant responses. The transcription of the 16 GATA3-nonresponding genes was clearly increased by the introduction of an active form of STAT6, STAT6VT. Therefore, although GATA3 has been recognized as a master regulator of Th2 cell differentiation, many Th2-specific genes are not regulated by GATA3 itself, but in collaboration with STAT6.

Domain and Interface Structures of Epitaxial PtSi

The crystalline perfection of epitaxial PtSi thin films and the microstructure of the PtSi/Si interface have been examined using transmission electron microscopy (TEM), including lattice image techniques. Epitaxial PtSi layers grow with domains which have three different positions on a (111) Si substrate. Inside a domain the crystalline perfection is high, and at the domain boundary no intermediate region has been observed. The undulation of the PtSi/Si interface is larger than that of other epitaxial silicide/Si interfaces. Despite the large undulation, a cross-sectional lattice image shows the epitaxial layer extends to the interface. The interface is abrupt in the epitaxial PtSi/Si system.

Electric-field control of solitons in a ferroelectric organic charge-transfer salt

The role of solitons in transport, dielectric, and magnetic properties has been revealed for the quasi-one-dimensional organic charge-transfer salt, TTF-QBrCl3 [tetrathiafulvalene (TTF)-2-bromo-3,5,6-trichloro-p-benzoquinone (QBrCl3)]. The material was found to be ferroelectric and hence the solitons should be located at the boundary of the segments with opposite electric polarization. This feature enabled the electric-field control of soliton density and hence the clear-cut detection of soliton contributions. The gigantic dielectric response in the ferroelectric phase is ascribed to the dynamical bound and creeping motions of spinless solitons.

Polycomb group gene product Ring1B regulates Th2-driven airway inflammation through the inhibition of Bim-mediated apoptosis of effector Th2 cells in the lung

Polycomb group (PcG) gene products regulate the maintenance of homeobox gene expression in Drosophila and vertebrates. In the immune system, PcG molecules control cell cycle progression of thymocytes, Th2 cell differentiation, and the generation of memory CD4 T cells. In this paper, we extended the study of PcG molecules to the regulation of in vivo Th2 responses, especially allergic airway inflammation, by using conditional Ring1B-deficient mice with a CD4 T cell-specific deletion of the Ring1B gene (Ring1B(-/-) mice). In Ring1B(-/-) mice, CD4 T cell development appeared to be normal, whereas the differentiation of Th2 cells but not Th1 cells was moderately impaired. In an Ag-induced Th2-driven allergic airway inflammation model, eosinophilic inflammation was attenuated in Ring1B(-/-) mice. Interestingly, Ring1B(-/-) effector Th2 cells were highly susceptible to apoptosis in comparison with wild-type effector Th2 cells in vivo and in vitro. The in vitro experiments revealed that the expression of Bim was increased at both the transcriptional and protein levels in Ring1B(-/-) effector Th2 cells, and the enhanced apoptosis in Ring1B(-/-) Th2 cells was rescued by the knockdown of Bim but not the other proapoptotic genes, such as Perp, Noxa, or Bax. The enhanced apoptosis detected in the transferred Ring1B(-/-) Th2 cells in the lung of the recipient mice was also rescued by knockdown of Bim. Therefore, these results indicate that Ring1B plays an important role in Th2-driven allergic airway inflammation through the control of Bim-dependent apoptosis of effector Th2 cells in vivo.

Stress analysis in the mandibular condyle during prolonged clenching: a theoretical approach with the finite element method

Parafunctional habits, such as bruxism and prolonged clenching, have been associated with functional overloading in the temporomandibular joint (TMJ), which may result in internal derangement and osteoarthrosis of the TMJ. In this study, the distributions of stress on the mandibular condylar surface during prolonged clenching were examined with TMJ mathematical models. Finite element models were developed on the basis of magnetic resonance images from two subjects with or without anterior disc displacement of the TMJ. Masticatory muscle forces were used as a loading condition for stress analysis during a 10 min clenching. In the asymptomatic model, the stress values in the anterior area (0.100 MPa) and lateral area (0.074 MPa) were relatively high among the five areas at 10 min. In the middle and posterior areas, stress relaxation occurred during the first 2 min. In contrast, the stress value in the lateral area was markedly lower (0.020 MPa) than in other areas in the symptomatic model at 10 min. The largest stress (0.050 MPa) was located in the posterior area. All except the anterior area revealed an increase in stress during the first 2 min. The present result indicates that the displacement of the disc could affect the stress distribution on the condylar articular surface during prolonged clenching, especially in the posterior area, probably leading to the cartilage breakdown on the condylar articular surface.

Advanced glycation end product is implicated in amyloid‐related kidney complications

BACKGROUND

Kidney failure is a common complication in familial amyloidotic polyneuropathy (FAP). It has been suggested that advanced glycation end products (AGEs) play an important role in the development and pathogenesis of FAP.

MATERIAL AND METHODS

To evaluate the impact of AGEs on FAP patients' kidney dysfunction, we measured AGE in serum and urine of 28 FAP patients and 18 healthy controls by AGE-specific enzyme-linked immunosorbent assay (ELISA). Immunohistochemistry utilizing antibodies to AGE and the receptor for AGE (RAGE) were used on kidney tissue from 3 FAP patients and 3 diabetic patients to disclose a correlation between amyloid deposits and AGE-RAGE.

RESULTS

The glomeruli of FAP patients were heavily deposited with amyloid and the glomerular size was enlarged. The space between Bowman's capsule and glomerulus was totally covered by the enlarged glomerulus. AGE and RAGE were deposited in glomeruli and tubuli and correlated with amyloid deposits. Decreased AGE levels in the liver-transplanted FAP patients' serum compared with that of non-transplanted patients were noted, and AGE concentration in serum tended to be higher in non-transplanted FAP patients compared with normal control subjects. There were no differences in the AGE urine levels in FAP patients compared with controls. No correlation could be found between AGE in urine and serum compared with serum albumin, serum creatinine and creatinine clearance.

CONCLUSIONS

The accumulation of AGE, RAGE and amyloid in the kidney of FAP patients suggests that these molecules play an important role in the origin and pathogenesis of renal failure in FAP patients.

Dynamical disorder of pi-molecular structures induced by proton dynamics in an organic ferroelectric compound

We have investigated the optical response resulting from the proton-pi-electron-molecular-skeleton coupled dynamics in an organic ferroelectric 55DMBP-Hia. Upon the ferroelectric-to-paraelectric transition, almost all of the vibrational modes below 500 cm;{-1} are anomalously blurred and amalgamated into the high-frequency tail of the polarization-relaxation mode. This indicates that the constituent molecular shape is no more well defined around T_{C} due to the dynamical disorder of the pi-conjugated structure originating from proton delocalization on the intermolecular bifurcated hydrogen bond.

Characterization of the immune escape phenotype of human gastric cancers with and without high-frequency microsatellite instability

Gastric cancers with and without high-frequency microsatellite instability (MSI-H) represent distinctive pathways of carcinogenesis. The aim of this study was to clarify if human leukocyte antigen (HLA) class I antigen subunits and antigen processing machinery (APM) components are differentially downregulated in these two groups of tumours. Using reverse transcription PCR (RT-PCR), loss of heterozygosity (LOH) analysis, methylation-specific PCR (MSP), DNA sequencing, immunohistochemistry, and flow cytometry, we analysed expression and/or alteration of HLA class I antigen subunits and APM components, including low molecular weight polypeptide proteasome subunit (LMP)2, LMP7, LMP10, transporter associated with antigen processing (TAP)1, TAP2, tapasin, proteasome activator (PA) 28alpha, and PA28beta in two stage-matched panels of 30 MSI-H and 30 microsatellite stable (MSS) gastric cancers. Mutations at coding microsatellites (cMS) located within beta2-microglobulin (beta2m) and genes encoding APM components, including endoplasmic reticulum (ER) chaperone protein genes, such as calnexin, SEC63, SEC31, and P4HB (p55), were also analysed. HLA class Ia transcripts were totally downregulated in 18.3% of cancer cases. Locus-specific downexpression of HLA-A, -B, and -C was detected in 41.7%, 45.0%, and 31.7% of cases. Loss of HLA-A was significantly more frequent in MSI-H cancers. The LOH ratios of the HLA-A, -B, and -C loci microsatellite markers were relatively low: 5/32 (15.6%) for D6S306, 4/32 (12.5%) for D6S258, 4/33 (12.1%) for D6S273, and 4/30 (13.3%) for D6S1666. Methylation of HLA-A, -B, and -C was detected in 38.3%, 40.0%, and 28.3% of cases. A significant association between methylation and reduction in expression was observed in gastric cancer tissues. Mutations at cMS of beta2m and APM components were detected in 3.3-46.7% of MSI-H cancers but in none of MSS cancers. These data show that gastric cancers have various defects in HLA class I antigen subunits and APM components and that the MSI phenotype is associated with frequent HLA-A inactivation and frameshift mutations of the beta2m and APM genes.

Intake of purple sweet potato beverage affects on serum hepatic biomarker levels of healthy adult men with borderline hepatitis

OBJECTIVE

To examine the effect of purple sweet potato (PSP) beverage rich in acylated anthocyanins on serum hepatic biomarkers in healthy Japanese men.

DESIGN

A randomized, double-blind, placebo-controlled, parallel study.

SETTING

Kumamoto in Japan.

SUBJECTS

Healthy adult men (30-60 years) with borderline hepatitis who had one or more of serum gamma-glutamyl transferase (GGT), aspertate aminotransferase (AST) and alanine aminotransferase (ALT) levels over normal ranges, and who were negative for hepatitis virus were openly recruited by an advertisement. Of the 48 persons enrolled, 38 (mean age 43.0 years (30-54 years)) completed the study.

METHODS

The subjects were randomly assigned to the PSP group and the placebo group. During the 8-week intervention, the subjects in the PSP group consumed two bottles of the PSP beverage with acylated anthocyanins (200.3 mg anthocyanins per 125 ml per bottle) per day, and the subjects in the placebo group, two bottles of a placebo beverage (1.7 mg anthocyanins per 125 ml per bottle). All of the data measured were analyzed by two-way repeated measures analysis of variance (ANOVA) with groups and times. The data of the hepatic markers were analyzed using the Dunnett multiple comparison among the time points and t-test between groups at the same time point. Two-sided P<0.05 were defined as the level of significance.

RESULTS

Serum GGT, AST and ALT levels showed interactions (P<0.05) between the beverage groups and time; the others were not affected. The PSP beverage group showed lower hepatic marker levels than the placebo group during the ingestion period, particularly the GGT level (-14.1 IU/l, 95% Confidence intervel (CI) -25.4 to -2.7, P=0.017 at 2 weeks; -16.8 IU/l, 95% CI -36.2 to 2.5, P=0.081 at 4 weeks; -26.7 IU/l, 95% CI -47.6 to -5.7, P=0.014 at 6 weeks and -27.9 IU/l, 95% CI -49.9 to -5.9; P=0.014 at 8 weeks). No correlation between alcohol consumption and each hepatic biomarker level before and after the ingestion was observed.

CONCLUSION

The intake of the PSP beverage significantly decreased the serum levels of hepatic biomarkers, particularly the GGT level, in healthy men with borderline hepatitis.

K-ras mutation in the endometrium of tamoxifen-treated breast cancer patients, with a comparison of tamoxifen and toremifene

The putative presence of a mutation in codon 12 of the K-ras gene was investigated in the endometrium of tamoxifen (TAM) and toremifene (TOR)-treated breast cancer patients. DNA was extracted from fresh cytologic samples of the endometrium in 86 TAM and 21 TOR-treated breast cancer patients. Mutations were detected by enriched PCR and an enzyme-linked mini-sequence assay (ELMA). K-ras mutation was found in 35 TAM-treated endometrial samples, and in only one TOR-treated endometrium (P<0.003). In 24 premenopausal patients, K-ras mutation was found in seven (43.8%) of 16 patients with less than 47 months of TAM treatment, while none was found in eight patients with more than 48 months of TAM treatment (P<0.03). In 62 postmenopausal-amenorrheic patients, K-ras mutation was found in three (15.8%) of 19 patients with less than 23 months of TAM treatment, while it was found in 16 (61.5%) of 26 patients with 24–47 months of TAM treatment and nine (52.9%) of 17 patients with more than 48 months of TAM treatment (P=0.002). The presence of K-ras mutation is significantly influenced by the duration of TAM treatment and menstrual status of the patients. TOR may have a lower potential genotoxicity than TAM.

Renal clearance of glycolaldehyde- and methylglyoxal-modified proteins in mice is mediated by mesangial cells through a class A scavenger receptor (SR-A)

AIMS/HYPOTHESIS

Glomerular mesangial expansion is a characteristic feature of diabetic nephropathy, and the accumulation of AGE in the mesangial lesion has been implicated as one of its potential causes. However, the route for the AGE accumulation in mesangial lesions in diabetic patients is poorly established.

METHODS

Glycolaldehyde-modified BSA (GA-BSA) and methylglyoxal-modified BSA (MG-BSA) were prepared as model AGE proteins, and their in vivo plasma clearance was examined in mice, and renal uptake by in vitro studies with isolated renal mesangial cells.

RESULTS

Both (111)In-GA-BSA and (111)In-MG-BSA were rapidly cleared from the circulation mainly by both the liver and kidney. Immunohistochemical studies with an anti-GA-BSA antibody demonstrated that intravenously injected GA-BSA accumulated in mesangial cells, suggesting that such cells play an important role in the renal clearance of circulating AGE proteins. Binding experiments at 4 degrees C using mesangial cells isolated from mice showed that (125)I-GA-BSA and (125)I-MG-BSA exhibited specific and saturable binding. Upon incubation at 37 degrees C, (125)I-GA-BSA and (125)I-MG-BSA underwent endocytic degradation by these cells. The binding of the ligands to these cells was inhibited by several ligands for scavenger receptors. The endocytic degradation of GA-BSA by mesangial cells from class A scavenger receptor (SR-A) knock-out mice was reduced by 80% when compared with that of wild-type cells. The glomerular accumulation of GA-BSA after its intravenous administration was attenuated in SR-A knock-out mice, as evidenced by immunohistochemical observations.

CONCLUSIONS/INTERPRETATION

These results raise the possibility that circulating AGE-modified proteins are subjected to renal clearance by mesangial cells, mainly via SR-A. This pathway may contribute to the pathogenesis of AGE-induced diabetic nephropathy.