A new therapeutic target for systemic lupus erythematosus: the current landscape for drug development of a toll-like receptor 7/8 antagonist through academia-industry-government collaboration

Systemic Lupus Erythematosus (SLE) is an autoimmune disease characterized by inflammation in multiple organs. A few treatments for SLE currently exist, including antimalarials, glucocorticoids, immunosuppressants, and two recently approved antibody agents; however, an unmet medical need remains for SLE. In addition, developing new drugs targeting SLE is a challenge since no specific biomarkers exist for the prediction of disease progression or drug response. A new drug candidate, E6742, is a specific antagonist of the toll-like receptors 7/8. To address the challenges for drug development in SLE, the process of developing E6742 utilizes a unique system of the Japan Agency for Medical Research and Development (AMED), the Cyclic Innovation for Clinical Empowerment (CiCLE) program. In the CiCLE program, a Phase 1 study in healthy adults was completed (NCT04683185) and a Phase 1/2 study in patients with SLE is on-going (NCT05278663). One of the potential benefits of this program is to conduct academia-led clinical research to identify specific biomarkers for E6742 in parallel with clinical studies (UMIN000042037). The aim of this review is to present current progress within the strategic collaboration of the AMED CiCLE program that optimize clinical development for patients with SLE.

Membrane lipid composition of Carnobacterium maltaromaticum CNCM I-3298, a highly cryoresistant lactic bacterium

The growing consumption of fermented products has led to an increasing demand for lactic acid bacteria (LAB), especially for LAB tolerant to freezing/thawing conditions. Carnobacterium maltaromaticum is a psychrotrophic and freeze-thawing resistant lactic acid bacterium. The membrane is the primary site of damage during the cryo-preservation process and requires modulation to improve cryoresistance. However, knowledge about the membrane structure of this LAB genus is limited. We presented here the first study of the membrane lipid composition of C. maltaromaticum CNCM I-3298 including the polar heads and the fatty acid compositions of each lipid family (neutral lipids, glycolipids, phospholipids). The strain CNCM I-3298 is principally composed of glycolipids (32%) and phospholipids (55%). About 95% of glycolipids are dihexaosyldiglycerides while less than 5% are monohexaosyldiglycerides. The disaccharide chain of dihexaosyldiglycerides is composed of α-Gal(1-2)-α-Glc chain, evidenced for the first time in a LAB strain other than Lactobacillus strains. Phosphatidylglycerol is the main phospholipid (94%). All polar lipids are exceptionally rich in C18:1 (from 70% to 80%). Regarding the fatty acid composition, C. maltaromaticum CNCM I-3298 is an atypical bacterium within the genus Carnobacterium due to its high C18:1 proportion but resemble the other Carnobacterium strains as they mostly do not contain cyclic fatty acids.

First-in-Human Study of the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of E6742, a Dual Antagonist of Toll-like Receptors 7 and 8, in Healthy Volunteers

The first-in-human phase I study for E6742, a dual toll-like receptor (TLR) 7 and TLR8 antagonist, has been conducted to assess the safety, tolerability, and pharmacokinetics of E6742 in healthy volunteers. In a single ascending dose (SAD) study, 42 subjects received 10-800 mg of E6742 in the fasted state, as well as a 100-mg cohort in the fed state for evaluating the effect of food. In a multiple ascending dose (MAD) study, 18 subjects received 100-400 mg of E6742 twice daily for 7 days. E6742 was rapidly absorbed with a median t_max ranging from 1.50 to 2.50 hours across dose groups under the fasted condition, and eliminated with a median t_½ ranging from 2.37 to 14.4 hours. After multiple oral doses, a steady state was reached by day 7. In the SAD study, dose proportionality was observed for C_max , AUC_(0-t) , and AUC_(0-inf) values of E6742 up to 800 mg, but these values were slightly less than dose proportional at 10 mg. In the MAD study, the C_max and AUC_(0-12h)ss of E6742 appeared to be almost dose proportionally increased between 100 and 200 mg, while these parameters showed more than a dose proportional increase at 400 mg. In addition to safety and good tolerability, this study demonstrated cytokine concentrations in cultured peripheral blood in response to E6742 were suppressed in a dose-dependent manner. Further clinical studies targeting systemic lupus erythematosus patients are currently underway.

Periarticular osteoporosis of the forearm correlated with joint destruction and functional impairment in patients with rheumatoid arthritis

The relationship between periarticular osteoporosis in the distal forearm and joint destruction or functional impairment in patients with rheumatoid arthritis (RA) is not sufficiently elucidated. From a single institutional cohort study, we found a strong correlation between periarticular forearm bone mineral density (BMD) and joint destruction or functional impairment.

INTRODUCTION

This study was conducted to investigate (1) the difference between various periarticular regions of interest (ROIs) of BMD of the forearm, (2) the correlation between periarticular forearm BMD and joint destruction and physical function, (3) the independent variables for predicting BMD of the forearm, and (4) the forearm BMD of different ROIs in the early stage of RA.

METHODS

We conducted a cross-sectional study in an RA cohort. Measurements included BMD of the distal forearm, joint destruction of the hands assessed by modified total Sharp score (mTSS), functional impairment assessed by a health assessment questionnaire (HAQ), and other clinical data. Variables affecting the forearm BMD values were analyzed by correlation and stepwise regression analyses.

RESULTS

Of the 405 patients enrolled in the present study, 370 (average age; 62.9 years) were identified as having definite RA with a complete set of data. BMD in the distal end of the forearm (BMDud) was significantly reduced compared with that in the distal third of the forearm (BMD1/3). In a stepwise regression analysis, the mTSS in BMD1/3 was an independent predicting variable, while age and partial HAQ scores associated with the upper extremity were common independent variables in BMDud and BMD1/3. BMDud was significantly less than BMD1/3, even in patients with a short duration of the disease. BMD1/3 was significantly less in non-remission group compared with that in remission group in patients with a short duration of the disease.

CONCLUSION

Periarticular BMD in the distal forearm is closely correlated with joint destruction and functional impairment in RA. Periarticular BMD in the distal forearm may be already reduced at the clinical manifestation of the disease.

Expression analysis of stemness genes in a rat thyroid cell line FRTL5

Detection and analysis of a small subpopulation of cells such as stem cells or cancer stem cells are recognized to be a key technique in a recent regeneration and cancer science. However, in the thyroid, no marker that identifies stem cells has been established yet. We previously established a novel method to analyze cells collected by fluorescence-activated cell sorting (FACS), named mRNA quantification after FACS (FACS-mQ). By using this method, the biological characteristics of the sorted cells can be determined by analyzing their gene expression profile. In this study, we analyzed the expression of stemness genes in a rat thyroid cell lines FRTL5 using FACS-mQ. 3 stemness genes, NANOG, ABCG2 and GATA4, were expressed in FRTL5. In FRTL5 cells, varied expression of thyroglobulin (TG) among cells was observed by flow cytometry. Cell populations with high or low TG expression were analyzed by FACS-mQ. The cell population with low TG expression showed increased expression of the stemness genes. Furthermore, Ki67-positive cells showed increased expression of TG, which suggested that cells with high TG proliferated rapidly. These results indicated that FRTL5 contains a cell population with high stemness gene expression and less differentiated features, resembling stem cells. These cells might regulate proliferation in FRTL5.

Discordance and accordance between patient's and physician's assessments in rheumatoid arthritis

OBJECTIVES

The American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) remission criteria for rheumatoid arthritis (RA) are more stringent than index-based criteria, making it more difficult to achieve a patient's global assessment (PGA) than an evaluator's global assessment (EGA). We investigated the reason for the discrepancy between the PGA and the EGA in a Japanese clinical cohort.

METHOD

We assessed clinical and laboratory variables in our clinical cohort. The frequency of remission achievement according to the ACR/EULAR remission criteria and predictors of the discrepancy between the PGA and EGA were analysed.

RESULTS

Of 370 patients with RA, 89 fulfilled PGA criteria and 167 patients fulfilled EGA criteria. The PGA was highly correlated with the visual analogue scale (VAS) pain score and non-inflammatory variables including Steinbrocker class and the Health Assessment Questionnaire Disability Index (HAQ-DI). Conversely, inflammatory variables, including swollen joint count (SJC), tender joint count (TJC), and C-reactive protein (CRP) levels, were significantly associated with the EGA. The main predictors of the discrepancy between the PGA and the EGA were patient's VAS pain score, SJC, and functional disability.

CONCLUSIONS

Increased pain and functional disability led to a discrepancy towards a worse PGA than EGA, whereas increased SJC led to an accordance towards a worse EGA.

Association between anti-U1 ribonucleoprotein antibodies and inflammatory mediators in cerebrospinal fluid of patients with neuropsychiatric systemic lupus erythematosus

Objective

We investigated possible associations between neurotoxic inflammatory mediators (IMs) and anti-U1RNP antibodies (Abs) in cerebrospinal fluid (CSF) of neuropsychiatric systemic lupus erythematosus (NPSLE).

Methods

Serum and CSF anti-U1RNP Abs were detected using an RNA-immunoprecipitation assay and CSF anti-U1RNP Ab levels were measured by ELISA. IFN-α, MCP-1 and IL-8 levels in CSF were determined by quantitative multiplex cytokine analysis. IM levels were compared among anti-U1RNP-positive and anti-U1RNP-negative NPSLE as well as other rheumatic disease controls (controls).

Results

Anti-U1RNP Abs were detected in serum (58%) and in CSF (18%) of 82 NPSLE patients. CSF MCP-1 levels were higher in NPSLE than in controls. CSF IFN-α level was higher in CSF anti-U1RNP Ab-positive than in -negative patients or controls. When limited to serum anti-U1RNP Ab-positive patients, however, levels of all three IMs in CSF were higher in CSF anti-U1RNP Ab-positive than in -negative patients. Anti-U1RNP Ab levels in CSF correlated with CSF MCP-1, but not IFN-α and IL-8 levels.

Conclusions

CSF anti-U1RNP Ab positivity is associated with increased level of CSF IFN-α. MCP-1 levels correlated with CSF anti-U1RNP Ab levels, whereas the increased CSF MCP-1 was not specific to CSF anti-U1RNP Ab-positive NPSLE.

Prolonged hybridization with a cRNA probe improves the signal to noise ratio for in-tube in situ hybridization for quantification of mRNA after fluorescence-activated cell sorting

We developed an in-tube in situ hybridization method for mRNA quantification after fluorescence-activated cell sorting (FACS-mQ). A specific RNA in a particular cell type is stained with a cRNA probe and a fluorescent dye, which allows the stained cells to be selected by FACS without excessive RNA degradation. Our previous protocol required 4 h for hybridization with a cRNA probe, which might not produce enough fluorescence signal for sorting genes with low expressions. We determined the effect of prolonged hybridization for in-tube in situ hybridization on quantitative measurement of intracellular RNAs. During the hybridization step, the quantity of ACTB mRNA decreased gradually until 4 h, but remained constant from 4 to 16 h below 63.6° C. For flow cytometry, cells hybridization with cRNA probes for TG mRNA at 60° C for 16 h showed both increased signal and decreased background fluorescence compared to those hybridized for 4 h. These results indicate that when performing in-tube in situ hybridization, hybridization temperature can be raised to 63.6° C and the hybridization step can be extended up to 16 h without excessive intracellular RNA degradation.

Preoperative concurrent chemoradiotherapy for stages II-IV oral squamous cell carcinoma: a retrospective analysis and the future possibility of this treatment strategy

This study evaluated survival in 154 patients with stages II-IV oral squamous cell carcinoma (OSCC) treated with preoperative concurrent chemoradiotherapy and assessed the future use of this treatment strategy. 14 patients exhibited advanced stage II, 73 exhibited stage III and 67 exhibited stage IV. All patients received 40Gy irradiation and concurrent cisplatin-based chemotherapy in two courses. Radical surgery was undertaken after 2-6 weeks. The clinical tumour response, histopathologic regression grade, residual tumour grade (RGrade) in the primary tumour and the level of residual pN+ were associated with prognosis. 90% of patients with complete response and 73% of patients with good partial response in the primary tumour were RGrade 0 (no residual tumour cells) or RGrade 1 (viable tumour cells remained within central superficial portion). In patients with complete response in the neck, residual pN+ was only seen in levels IB (8%) and IIA (8%); the higher the level of residual pN+, the lower the survival rate (p<0.0001). This treatment strategy was excellent for stages II-IV OSCC. It may be possible to perform minimally invasive surgery in which the extent of resection in primary tumour and neck is reduced in patients who achieve good response following preoperative chemoradiotherapy.

CD52 as a molecular target for immunotherapy to treat acute myeloid leukemia with high EVI1 expression

Ecotropic viral integration site 1 (EVI1) is an oncogenic transcription factor in human acute myeloid leukemia (AML) with chromosomal alterations at 3q26. Because a high expression of EVI1 protein in AML cells predicts resistance to chemotherapy with a poor outcome, we have searched for molecular targets that will treat these patients with AML. In this study, we determined that CD52, which is mainly expressed on lymphocytes, is highly expressed in most cases of AML with a high EVI1 expression (EVI1(High)). CAMPATH-1H, a humanized monoclonal antibody against CD52, has been used to prevent graft-versus-host disease and treat CD52-positive lymphoproliferative disorders. Here, we investigated the antitumor effect of CAMPATH-1H on EVI1(High) AML cells. CAMPATH-1H significantly inhibited cell growth and induced apoptosis in CD52-positive EVI1(High) leukemia cells. Furthermore, CAMPATH-1H induced complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity against CD52-positive EVI1(High) leukemia cells. After an intravenous injection of CAMPATH-1H into NOD/Shi-scid/IL-2Rγ;null mice with subcutaneous engraftment of EVI1(High) leukemia cells, tumor growth rates were significantly reduced, and the mice survived longer than those in the phosphate-buffered saline-injected control group. Thus, CAMPATH-1H is a potential therapeutic antibody for the treatment of patients with EVI1(High) leukemia.

Supplementation of CD4+CD25+ regulatory T cells suppresses experimental autoimmune uveoretinitis

AIMS

To investigate whether supplementation of natural CD4+CD25+ regulatory T cells ameliorates mouse experimental autoimmune uveoretinitis (EAU) induced by CD4+ T cell-dependent interphotoreceptor retinoid-binding protein (IRBP).

METHODS

C57BL/6 mice were immunised with human interphotoreceptor retinoid-binding protein peptide 1-20 (IRBP(1-20)), and IRBP(1-20)-sensitised T cells were obtained. CD4+CD25+ T cells derived from naive mice were cocultured with IRBP(1-20)-sensitised T cells, and their proliferation responses and cytokine production were measured. In addition, CD4+CD25+ T cells were transferred intravenously into mice 7 or 15 days after immunisation with IRBP(1-20), and the severity of EAU and T cell proliferation responses were evaluated.

RESULTS

CD4+CD25+ regulatory T cells effectively inhibited both the proliferation of, and interleukin (IL)2, IL5 and interferon (IFN)gamma production by, IRBP(1-20)-sensitised T cells. Adoptive transfer of CD4+CD25+ regulatory T cells to IRBP(1-20)-immunised mice conferred considerable protection from EAU development and inhibition of T cell proliferation responses to IRBP(1-20).

CONCLUSION

These findings show that natural CD4+CD25+ regulatory T cells possess the ability to inhibit activation of IRBP-reactive T cells that have been already sensitised in vivo, and adoptive transfer of these cells ameliorates EAU even in the effector phase. Supplementation of natural CD4+CD25+ regulatory T cells may have therapeutic potential for effective treatment of uveitis.

FKBP12 functions as an adaptor of the Smad7-Smurf1 complex on activin type I receptor

The cytoplasmic immunophilin FKBP12, a 12 kDa FK506-binding protein, has been shown to act as an inhibitor for transforming growth factor-beta (TGF-beta) signaling. FKBP12 binds to the glycine- and serine-rich motif (GS motif) of the TGF-beta type I receptor, and functions as a secure switch to prevent the leaky signal. Upon stimulation with ligand, FKBP12 is released from the receptor to fully propagate the signal. We found that activin, a member of TGF-beta superfamily, also induced the dissociation of FKBP12 from the activin type I receptor (ALK4). However, we observed that the released FKBP12 associates again with the receptor a few hours later. FKBP12 also interacted with another inhibitory molecule of activin signal, Smad7, in an activin-dependent manner, and formed a complex with Smad7 on the type I receptor. FK506, a chemical ligand for FKBP12, which dissociates FKBP12 from the receptor, decreased the interaction between Smad7 and Smad ubiquitin regulatory factor 1 (Smurf1). FK506 also inhibited the ubiquitination of the type I receptor by Smurf1. These findings indicate a new inhibitory function of FKBP12 as an adaptor molecule for the Smad7-Smurf1 complex to regulate the duration of the activin signal.

Solution properties and photonuclease activity of cationic bis-porphyrins linked with a series of aliphatic diamines

The development of efficient photo-induced DNA cleavage agents has been of particular interest for biomedical applications such as cancer photodynamic therapy (PDT). Toward this objective, we synthesized a series of cationic bis-porphyrins with various lengths of diamino alkyl linkage, N,N'-bis[4-[10,15,20-tris(1-methylpyridinium-4-yl)porphyrin-5-yl]benzoyl]oligomethylenediamine hexaiodide. They were expected to show more efficient photocleavage of DNA than unichromophore meso-tetrakis(4-N-methylpyridiniumyl)porphine (TMPyP), which is well known to cleave DNA effectively on illumination. The cationic bis-porphyrins were found to self-aggregate in aqueous solution, and the aggregation property was accounted for by the formation of an intermolecular dimer. Because conservative-type circular dichroism spectra of the bis-porphyrins were induced in the Soret region on binding to calf thymus DNA, we assigned their binding mode to outside self-stacking on the DNA surface. Their photonuclease activity using plasmid DNA decreased as the number of their linker hydrocarbons increased, and was well correlated with their tendency for dimerization. The inhibitory effect of azide anion, N3-, and the enhancement effect of D2O suggest that singlet oxygen was probably involved in the photocleavage of DNA.

[Transient myelodysplasia associated with human parvovirus B19 infection in a child without underlying disease]

Human parvovirus B19 (HPV-B19) infection is known to frequently induce aplastic crisis in patients with hemolytic anemia, but rarely causes hematological disorders in healthy subjects. We report a 5-year-old boy who showed transient myelodysplasia associated with HPV-B19 infection. He was admitted with severe nasal bleeding, and laboratory data showed marked thrombocytopenia (1,000/microliter), anemia (Hb: 8.4 g/dl), and mild leukopenia (3,000/microliter). A bone marrow smear revealed myelodysplastic changes in three cell lineages, but no giant proerythroblasts or megakaryocytes. The pancytopenia and myelodysplastic changes were resolved spontaneously within a week without any medication other than transfusion of red blood cells and platelets. Serological examination revealed an elevation of IgG antibody against HPV-B19 on days 15 and 120 and its subsequent decrease thereafter, although HPV-B19-specific DNA was not detected in the serum at onset. The clinical course and laboratory data suggest an etiologic role of HPV-B19 infection in the occurrence of transient myelodysplasia.

Intracellular and extracellular control of activin function by novel regulatory molecules

Activin signal transduction is regulated through multiple mechanisms. We have identified novel regulatory proteins that control activin functions either intracellularly or extracellularly. As intracellular molecules, PSD-95/Dlg/ZO-1 (PDZ) proteins that specifically associate with activin type II receptors (ActRIIs) were identified. We have named the molecules as activin receptor-interacting proteins (ARIPs). ARIP1 has two WW domains and five PDZ domains, associates not only with ActRIIs but also with Smads, and controls activin functions intracellularly in neuronal cells. Another ARIP we have found has only one PDZ domain, and is likely to be involved in intracellular trafficking and sorting of activin receptor complexes in the cell. As an extracellular regulatory protein, we have identified a novel follistatin-like protein, named follistatin-related gene (FLRG). Like follistatins, FLRG binds activins and bone morphogenetic proteins (BMPs) and controls their functions extracellularly. The mode of association of follistatin and FLRG with activins and their expression patterns are different, suggesting the distinct functions of follistatin and FLRG in vivo.

A cellular variant of supratentorial hemangioblastoma

Supratentorial hemangioblastomas are rarely seen, especially in children and adolescents. We report the case of a 17-year-old male with supratentorial hemangioblastoma. Neuroimaging demonstrated a cystic lesion within the right parietal lobe. Systemic examination revealed no abnormality. The lesion was not attached to the dura and was not associated with von Hippel-Lindau disease. It was very difficult to confirm the final diagnosis of this case, in spite of extensive examination by light microscopy, immunohistochemical studies, and electron microscopy.

Differential gene expression of beta-1,4-galactosyltransferases I, II and V during mouse brain development

Since most brain glycoproteins from beta-1,4-galactosyltransferase (beta-1,4-GalT) I knockout mice were galactosylated without apparent reduction the gene expression of novel beta-1,4-GalTs II and V which are involved in N-linked oligosaccharide biosynthesis in addition to beta-1,4-GalT I was studied during mouse brain development. Isolation and characterization of beta-1,4-GalT II and V cDNAs from mouse brains indicates that they are also functioning in the brain. Northern blot analysis revealed that the beta-1,4-GalT I gene is expressed mainly in mid-embryonic stages, while the expression level of beta-1,4-GalT II transcript remains constant and of beta-1,4-GalT V transcript increases during mouse brain development after birth. In situ hybridization revealed that beta-1,4-GalT II and V signals are present in most neural cells, with a marked difference between them in the hippocampus of adult mouse brain tissue. The differential gene expression of beta-1,4-GalTs I, II and V during mouse brain development could affect the differential galactosylation of brain glycoproteins, as revealed by lectin blot analysis.

Identification and characterization of a novel follistatin-like protein as a binding protein for the TGF-beta family

Follistatin is an activin-binding protein that prevents activin from binding to its receptors and neutralizes its activity. Follistatin also binds bone morphogenetic proteins (BMPs). In this study, we report the identification of a novel follistatin-like protein from mouse. The mouse cDNA encodes a 256-residue precursor and most likely a mouse homologue of human FLRG, which was found at the breakpoint of the chromosomal rearrangement in a B-cell line. Whereas follistatin has three follistatin domains, which are presumed to be growth factor binding motifs, FLRG possesses only two follistatin domains. Northern blotting revealed that mRNAs for FLRG were abundantly expressed in heart, lung, kidney, and testis in mouse. The recombinant mouse FLRG proteins were found to have binding activity for both activin and bone morphogenetic protein-2. Like follistatin, FLRG has higher affinity for activin than for BMP-2. The FLRG protein inhibited activin-induced and BMP-2-induced transcriptional responses in a dose-dependent manner. Glutathione S-transferase fusion proteins encoding various regions of FLRG were produced and studied. Ligand blotting using (125)I-activin revealed that the COOH-terminal region containing the second follistatin domain was able to bind activin. Our finding implies that cellular signaling by activin and BMPs is tightly regulated by multiple members of the follistatin family.

Interaction between inflammatory cells and heparin-surface-modified intraocular lens

PURPOSE

To investigate the interaction and adherence of inflammatory cells to a heparin-surface-modified intraocular lens (HSM IOL).

SETTING

Department of Ophthalmology, Tokyo Medical University Hospital, Tokyo, Japan.

METHODS

Splenic mononuclear leukocytes from rats with experimental autoimmune uveitis were cultured with the optic of an HSM IOL for 96 hours. The number of adherent cells on the HSM IOL surface was measured with and without the addition of interphotoreceptor retinoid-binding protein and concanavalin A (ConA) to the culture medium. The adherent cells were observed under a light microscope or a scanning electron microscope.

RESULTS

Interphotoreceptor retinoid-binding protein and ConA increased the number of adherent cells on the HSM IOL relative to the control. Adherent cells on the HSM IOL were small and round, considered to be mainly lymphocytes.

CONCLUSION

Activated lymphocytes tended to adhere to the surface of the HSM IOL.

Expression of a TGF-beta1 inducible gene, TSC-36, causes growth inhibition in human lung cancer cell lines

TSC-36 (TGF-beta1-stimulated clone 36) is a TGF-beta1 inducible gene whose product is an extracellular glycoprotein that contains a single follistatin module. TSC-36 is highly expressed in the lung, but its physiological function is unknown. In an attempt to elucidate it, we investigated the effect of TSC-36 on proliferation of human lung cancer cell lines. We found a correlation between expression of TSC-36 and cell growth: TSC-36 mRNA was not detected in cells derived from small cell lung cancer (SCLC) cells, a highly aggressive neoplasm, but was detected in some non-small cell lung cancer (NSCLC) cells, a moderately aggressive neoplasm. This suggested an antiproliferative function for TSC-36. To address this question, NSCLC PC-14 cells, which express very low level of TSC-36 protein, were transfected with TSC-36 cDNA and the proliferative capacity of stable transfectants was determined by measuring the doubling time, colony forming activity in soft agar and the level of incorporation of (3)H-thymidine into DNA. Under normal culture conditions, the transfected cells showed a longer doubling time, lower plating efficiency and lower rate of DNA synthesis than the parental cells and the control neo transfectant cells. These findings suggested that expression of TSC-36 caused growth inhibition in human lung cancer cells.

Analysis of the role of egg integrins in sperm-egg binding and fusion

Sperm-egg fusion is believed to be mediated via specific molecular interactions. Integrin alpha6beta1 is a strong candidate for a sperm receptor on the egg plasma membrane. However, the ability of the egg integrin alpha6beta1 to interact with molecules on intact sperm has not yet been proven. In this report, possible involvement of integrin alpha6beta1 in sperm-egg interactions was examined by biochemical and immunocytochemical analyses. To identify egg molecules that specifically interact with sperm, we first incubated sperm with biotin-labeled egg surface proteins. Under this condition, solubilized proteins from eggs inhibited sperm-egg fusion. Western blot analysis under reducing conditions indicated that a major-labeled band of 135 kDa bound to sperm. An immunodepletion experiment using the anti-integrin alpha6 antibody GoH3 indicated that the 135 kDa egg surface molecule that bound to sperm was the integrin alpha6 subunit. To investigate the potential involvement of integrin alpha6beta1 in sperm-egg fusion, we next examined the localization of integrin alpha6 and beta1 subunits before and after fertilization by confocal laser microscopy. At an early stage of sperm-egg fusion, the integrin alpha6 and beta1 subunits were accumulated at the sperm binding site. The frequency of cluster formation was closely related to that of sperm-egg fusion, indicating that integrin receptors are accumulated by sperm destined for fusion. Taken together, these results strongly suggest that the integrin alpha6beta1 is involved in sperm-egg binding leading to fusion via direct association of the integrin alpha6 with sperm.

[Molecular biological analysis of retinal and streptococcal heat-shock protein 60]

PURPOSE

The observation of recurrent oral aphtha preceding ocular inflammation in patients with Behçet's disease suggests a role of oral Streptococcus in the etiology of this disease. Heat-treated Streptococcus antigen can induce ocular inflammation or systemic symptoms in Behçet's disease patients. Furthermore, the presence of an autoantibody against retinal heat-shock protein 60 (HSP 60) has been detected in the sera of these patients. Injection of extracted retinal HSP 60 also induces experimental uveitis in treated rats. The characteristics of retinal HSP 60 and HSP 60 from S. pyogenes were evaluated using a molecular biological approach.

METHODS

The gene encoding HSP 60 was isolated by polymerase chain reaction (PCR) from a bovine retinal cDNA library and from S. pyogenes DNA. The DNA sequence of the HSP 60 coding region was determined, and the amino acid sequences of the encoded proteins were predicted from the DNA sequence. The synthetic peptide (50 nmol) was emulsified with Freund's complete adjuvant and injected into rats.

RESULTS

Comparison of the amino acid sequences of Streptococcal and bovine retinal HSP 60 revealed about 200 residue regions with 47% homology. Experimental uveitis was mainly induced in rats inoculated with retinal HSP 60-derived peptide or Streptococcus HSP 60-derived peptide that is equivalent to residues 245-259 of human HSP 65.

DISCUSSION

The retinal and Streptococcal HSP 60 amino acid composition is thought to be important and useful for investigating the mechanisms involved in the induction of Behçet's disease.

Identification and characterization of a PDZ protein that interacts with activin type II receptors

We have identified a mouse PDZ protein that interacts with the activin type IIA receptor (ActRIIA), which we named activin receptor-interacting protein 1 (ARIP1). By using yeast two-hybrid screening, we isolated a cDNA clone of ARIP1 from a mouse brain cDNA library. We detected two forms of ARIP1, ARIP1-long and ARIP1-short, which may be produced by alternative splicing. ARIP1-long had one guanylate kinase domain in the NH(2)-terminal region, followed by two WW domains and five PDZ domains (PDZ1-5). ARIP1-short had a deletion in the NH(2)-terminal region and lacked the guanylate kinase domain. Both forms interacted with ActRIIA through PDZ5. The COOH-terminal residues of ActRIIA (ESSL) agree with a PDZ-binding consensus motif, and ARIP1 recognized the consensus sequence. ARIP1 interacts specifically with ActRIIA among the receptors for the transforming growth factor beta family. Interestingly, ARIP1 also interacted with Smad3, which is an activin/transforming growth factor beta intracellular signaling molecule. The mRNA of ARIP1 was more abundant in the brain than in other tissues. Overexpression of ARIP1 controls activin-induced and Smad3-induced transcription in activin-responsive cell lines. These findings suggest that ARIP1 has a significant role in assembling activin signaling molecules at specific subcellular sites and in regulating signal transduction in neuronal cells.

Steroid sensitivity and postoperative course of seven patients with Behçet's disease

Systemic administration of steroids to patients with Behçet's disease in Japan is often followed by a worsening in ocular symptoms. The sensitivity of 7 patients with Behçet's disease to steroids which were administered during and after intraocular surgery was therefore measured, and their postoperative course was reviewed. Three of the 7 showed a low steroid sensitivity, and the frequency of postoperative inflammatory episodes and the intraocular pressure were both higher for this group than for the 4 who showed high steroid sensitivity.

A metalloproteinase inhibitor prevents acute graft-versus-host disease in mice after bone marrow transplantation

Tumor necrosis factor (TNF) and Fas ligand (FasL) have been implicated in the pathogenesis of graft-versus-host disease (GVHD), which is a major complication after allogeneic bone marrow transplantation. We have examined the ameliorating effect of a metalloproteinase inhibitor (KB-R7785) that inhibits TNF-alpha and FasL release in a murine acute GVHD model after bone marrow transplantation. Administration of KB-R7785 to irradiated (BALB/c x C57BL/6) F1 mice that received C57BL/6 bone marrow cells and spleen cells reduced the mortality and weight loss in association with minimal signs of GVHD pathology in the liver, intestine, and hematopoietic tissues. The KB-R7785 treatment did not affect hematopoietic reconstitution by donor cells. Therefore, KB-R7785 could be a potent therapeutic agent for GVHD after bone marrow transplantation.

Behçet's disease and antibody titers to various heat-shock protein 60s

It has been suggested that the 65 kDa heat-shock protein (HSP) of Streptococcus in recurrent aphthae within the oral cavity may be involved in the uveoretinitis of Behçet's disease, possibly through sensitization of the immune system. To investigate this possibility, we examined serum antibody titers for various members of the 60 kDa family of HSPs and their implications with regard to a role for HSP60s in Behçet's disease. We isolated HSP60 of Streptococcus pyogenes from the margin of oral aphthae in one Behçet's disease patient with severe uveoretinitis and the HSP60s of Yersinia enterocolitica, retinoblastoma cell line clone Y79, and bovine retinal extract and investigated the reaction of each of these HSP60s with 100-fold diluted serum samples from 20 Behçet's disease patients using anti-HSP60 antibody titers determined by ELISA. The anti- Streptococcus HSP60 antibody and anti-retinal HSP60 antibody titers of the 100-fold diluted serum samples from the Behçet's disease patients were both significantly higher than those of similarly diluted serum samples from healthy donors. The results of the ELISA antibody titer assay showed that, although the various HSP60s share a common basic antigenicity, they differed in reactivity to the anti-HSP60 antibodies in the sera of the Behçet's disease patients. The results indicate that subtle but significant differences exist in the antigenicity of the various HSP60s tested, all of which share a common basic antigenicity and are of approximately the same molecular weight, and suggest that an immuno-cross-reaction between retinal and streptococcal HSPs and a related autoimmune response may be involved in the development of Behçet's disease.