Distinct Characteristics of Sweet's Syndrome of the Scrotum Caused by All-trans Retinoic Acid in a Patient with Acute Promyelocytic Leukemia.

Induction therapy with all-trans retinoic acid (ATRA) is effective for acute promyelocytic leukemia (APL). ATRA induces neutrophil differentiation and its associated side effects. The differentiation syndrome is the most characterized ATRA-induced adverse effect. Sweet's syndrome, also known as neutrophilic dermatosis, is another form of ATRA-associated disease characterized by neutrophil infiltrating erythema that develops with fever. This is a case of a 34-year-old Japanese man diagnosed with APL. At the onset, the patient did not have skin involvement of APL cells. He was treated with ATRA and induction chemotherapy with idarubicin and cytarabine. Scrotal skin rash occurred at day 14, which developed into scrotal ulceration up to day 28 even after eliminating APL cells in his peripheral blood. Sweet's syndrome is a pathological diagnosis of scrotal skin ulceration representing neutrophil infiltration. The infiltrating neutrophils showed PML-RARα rearrangement. The patient was diagnosed with ATRA-associated Sweet's syndrome with skin ulcer. His cutaneous lesion did not respond to intravenous prednisolone therapy; thereby, ATRA was discontinued. After the cessation of ATRA, the skin lesion improved in the next week. We confirmed he achieved a complete response after induction chemotherapy. In our observation, ATRA-associated Sweet's syndrome is characterized by the following clinical manifestations: preferable occurrence in the scrota, tend to progress into skin ulcer, and pathogenicity associated with PML-RARα-positive matured neutrophils. The etiology, pathogenesis, and risk factors of ATRA-associated scrotal ulceration were discussed in the literature review.

Status of In-Hospital Acute Ischemic Stroke Treated by Mechanical Thrombectomy.

Objective: To elucidate the current state of in-hospital acute ischemic stroke under the introduction of acute-phase mechanical thrombectomy. Methods: The study included 18 consecutive patients with in-hospital cerebral infarction who underwent thrombectomy between April 2014 and March 2020 at St. Marianna University School of Medicine Yokohama City Seibu Hospital. We analyzed the primary disease, department responsible for treatment, modified Rankin Scale (mRS) scores before onset and on discharge, status of onset, treatment course, and so on. Results: The mean age was 79.9 (66-93) years. There were nine females. The admission methods included scheduled admission in 5 patients and non-scheduled admission in 13 patients. The primary diseases consisted of malignant tumors in five patients and heart disease in four patients. The departments responsible for treatment consisted of the Department of Digestive Surgery for six patients and Department of Cardiology for three patients. The mRS score before admission was evaluated as 0-2 in 15 patients and 3-5 in 3 patients. The embolism was evaluated as cardiogenic in 14 patients. Antithrombotic therapy was discontinued before the onset of cerebral infarction in three patients. The mean interval from onset or last well known (LWK) until CT/MRI and puncture was 88.4 and 157.6 minutes. The median Alberta stroke program early CT score (ASPECTS; minimum-maximum) was 8 (2-10). Tissue plasminogen activator (t-PA) was administered to five patients. Concerning the degree of recanalization, the thrombolysis in cerebral infarction (TICI) grade was evaluated as 1 to 2a in 2 patients and 2b to 3 in 16. In the latter, the mean interval from onset or final onset-free confirmation until recanalization was 197.7 minutes. mRS score on discharge was evaluated as 0-2 in four patients, 3-5 in nine, and 6 in five patients. The mortality was related to a primary disease requiring admission in three patients. Conclusion: In-hospital onset cerebral infarction was markedly influenced by the primary disease requiring admission. Even when favorable recanalization was achieved, the number of patients with a favorable outcome was small.

Layilin enhances the invasive ability of malignant glioma cells via SNAI1 signaling.

BACKGROUND: Malignant gliomas are characterized by high invasive ability. In this study, we investigated roles of layilin, a C-type lectin-homologous protein, in the invasive ability of malignant glioma cells. METHODS: Expression of layilin was investigated by western blotting in the malignant glioma cell lines of U251-MG, A172, and T98G and in astrocytes. The effects of layilin-knockdown on the expression and protein levels of snail family transcriptional repressor 1 (SNAI1), a transcriptional factor involved in the acquisition and enhancement of invasive ability in malignant gliomas, and on the expression of its target genes, matrix metalloproteinase 2 (MMP2), MMP9, and collagen type I alpha 1 chain (COL1A1), were investigated by qPCR and/or western blotting. Furthermore, the effects of layilin-knockdown on the expression and protein levels of metastasis associated 1 family member 3 (MTA3), a transcriptional repressor of SNAI1, were also investigated by qPCR and western blotting. Finally, the effects of layilin-knockdown on the invasive ability of the cells were investigated by a wound healing assay. RESULTS: All the tested malignant glioma cells highly expressed layilin, compared to astrocytes, one of representative glial cell types. Layilin-knockdown reduced SNAI1 both at the mRNA and protein levels in A172 cells, and consequently mRNA levels of MMP2, MMP9, and COL1A1 were also reduced. Furthermore, layilin-knockdown increased nuclear protein levels of MTA3 in A172 cells. Notably, layilin-knockdown suppressed the invasive ability of the cells. CONCLUSION: Layilin up-regulates the expression of SNAI1 via down-regulation of MTA3. This process enhances the invasive ability of malignant glioma cells.

CD4 memory T cells develop and acquire functional competence by sequential cognate interactions and stepwise gene regulation.

Memory CD4(+) T cells promote protective humoral immunity; however, how memory T cells acquire this activity remains unclear. This study demonstrates that CD4(+) T cells develop into antigen-specific memory T cells that can promote the terminal differentiation of memory B cells far more effectively than their naive T-cell counterparts. Memory T cell development requires the transcription factor B-cell lymphoma 6 (Bcl6), which is known to direct T-follicular helper (Tfh) cell differentiation. However, unlike Tfh cells, memory T cell development did not require germinal center B cells. Curiously, memory T cells that develop in the absence of cognate B cells cannot promote memory B-cell recall responses and this defect was accompanied by down-regulation of genes associated with homeostasis and activation and up-regulation of genes inhibitory for T-cell responses. Although memory T cells display phenotypic and genetic signatures distinct from Tfh cells, both had in common the expression of a group of genes associated with metabolic pathways. This gene expression profile was not shared to any great extent with naive T cells and was not influenced by the absence of cognate B cells during memory T cell development. These results suggest that memory T cell development is programmed by stepwise expression of gatekeeper genes through serial interactions with different types of antigen-presenting cells, first licensing the memory lineage pathway and subsequently facilitating the functional development of memory T cells. Finally, we identified Gdpd3 as a candidate genetic marker for memory T cells.

Distinct cellular pathways select germline-encoded and somatically mutated antibodies into immunological memory.

One component of memory in the antibody system is long-lived memory B cells selected for the expression of somatically mutated, high-affinity antibodies in the T cell-dependent germinal center (GC) reaction. A puzzling observation has been that the memory B cell compartment also contains cells expressing unmutated, low-affinity antibodies. Using conditional Bcl6 ablation, we demonstrate that these cells are generated through proliferative expansion early after immunization in a T cell-dependent but GC-independent manner. They soon become resting and long-lived and display a novel distinct gene expression signature which distinguishes memory B cells from other classes of B cells. GC-independent memory B cells are later joined by somatically mutated GC descendants at roughly equal proportions and these two types of memory cells efficiently generate adoptive secondary antibody responses. Deletion of T follicular helper (Tfh) cells significantly reduces the generation of mutated, but not unmutated, memory cells early on in the response. Thus, B cell memory is generated along two fundamentally distinct cellular differentiation pathways. One pathway is dedicated to the generation of high-affinity somatic antibody mutants, whereas the other preserves germ line antibody specificities and may prepare the organism for rapid responses to antigenic variants of the invading pathogen.

Lyn signaling to upregulate GANP is critical for the survival of high-affinity B cells in germinal centers of lymphoid organs.

Signals through BCR and costimulatory molecules play essential roles in selecting high-affinity B cells with Ig V-region mutations in the germinal centers (GCs) of peripheral lymphoid organs. Lyn-deficient (lyn(-/-)) mice show impaired BCR signal triggering for cell proliferation and GC formation, causing hyper-IgM, and display autoimmunity after aging. In this study, we demonstrate that Lyn-mediated signaling to upregulate GANP is essential for the survival of mature GC-like (mGC) B cells with high-affinity type BCR mutations upon Ag immunization. Transgenic ganp expression into lyn(-/-) mice did not recover the Lyn-deficient phenotype with regard to B cell differentiation, serum Igs, and impaired GC formation in spleens after immunization with nitrophenyl-chicken γ-globulin, but it markedly rescued cell survival of mGC B cells by suppressing DNA damage, thereby increasing the frequency of the Trp(33)-to-Leu mutation in the IgV(H)-186.2 region and affinity maturation of nitrophenyl-binding B cells. GANP may play a critical role in Lyn-mediated signaling for the selection of high-affinity B cells in peripheral lymphoid organs.

Genome-wide identification and characterization of transcripts translationally regulated by bacterial lipopolysaccharide in macrophage-like J774.1 cells.

Although Escherichia coli LPS is known to elicit various proinflammatory responses in macrophages, its effect on the translational states of transcripts has not yet been explored on a genome-wide scale. To address this, we investigated the mRNA profiles in polysomal and free messenger ribonucleoprotein particle (mRNP) fractions of mouse macrophage-like J774.1 cells, using Affymetrix Mouse Genome 430 2.0 GeneChips. Comparison of the mRNA profiles in total cellular, polysomal, and free mRNP fractions enabled us to identify transcripts that were modulated at the translational level by LPS: among 19,791 transcripts, 115 and 418 were up- and downregulated at 1, 2, or 4 h after LPS stimulation (100 ng/ml) in a translation-dependent manner. Interestingly, gene ontology-based analysis suggested that translation-dependent downregulated genes frequently include those encoding proteins in the mitochondrial respiratory chain. In fact, the mRNA levels of some transcripts for complexes I, IV, and V in the mitochondrial respiratory chain were translationally downregulated, eventually contributing to the decline of their protein levels. Moreover, the amount of metabolically labeled cytochrome oxidase subunit Va in complex IV was decreased without any change of its mRNA level in total cellular fraction after LPS stimulation. Consistently, the total amounts and activities of complexes I and IV were attenuated by LPS stimulation, and the attenuation was independent of nitric oxide. These results demonstrated that translational suppression may play a critical role in the LPS-mediated attenuation of mitochondrial oxidative phosphorylation in a nitric oxide-independent manner in J774.1 cells.

Formalin-treated UV-inactivated SARS coronavirus vaccine retains its immunogenicity and promotes Th2-type immune responses.

The demand for rapid and simple development of a vaccine against a newly emerging infectious disease is increasing worldwide. We previously revealed that UV-inactivated severe acute respiratory syndrome (SARS)-associated coronavirus (SARS-CoV) virions (UV-V) elicited high levels of humoral immunity and a weak Th0 response in mice immunized subcutaneously. To ensure the safety of such a whole inactivated SARS-CoV vaccine, we additionally treated the UV-V vaccine with formalin, resulting in the UV-F-V vaccine. Analysis of the immunogenicity of the UV-F-V+alum vaccine in mice revealed that it generated comparable neutralizing serum anti-SARS-CoV IgG antibody levels as the UV-V+alum vaccine. Moreover, both vaccines induced similar frequencies of anti-SARS-CoV IgG antibody-producing cells in bone marrow. Interestingly, the UV-F-V vaccine induced fewer IgG(2a) subtype antibodies and higher interleukin-4 production in vaccinated mice than did UV-V. Thus, UV-F-V imposes a Th2-type bias on the immune response, unlike UV-V. We propose here that doubly-inactivated SARS-CoV virions by UV and formalin constitute a safe vaccine that may effectively induce neutralizing antibodies in humans.

3-Morpholinosydnonimine hydrochloride induces p53-dependent apoptosis in murine primary neural cells: a critical role for p21(ras)-MAPK-p19(ARF) pathway.

In some neurological disorders, excessive nitric oxide (NO, nitrogen monoxide) produced by inducible and/or neuronal nitric oxide synthases (iNOS and nNOS) is able to combine with superoxide (O(minus sign)(2)) to form peroxynitrite (ONOO(minus sign)), which can then induce p53-dependent neural apoptosis. In the present study, experiments using p53 knock-out mice primary neural cells revealed that 3-morpholinosydnonimine hydrochloride (SIN-1), a peroxynitrite donor, triggered apoptosis, while p53-transcriptional activity was effectively suppressed in the absence of p53 molecules. This shows that SIN-1 was able to induce p53-dependent apoptosis in murine primary neural cells. The mechanism responsible for the SIN-1-induced accumulation of p53 molecules was then analyzed. Western blot analysis indicated that p53 accumulation caused by SIN-1 did not require p53 phosphorylation, whereas SIN-1 treatment triggered MAP kinase (MAPK) phosphorylation and pretreatment with the MAP kinase kinase (MEK) inhibitor U0126 inhibited p53 accumulation. Pretreatment of the neural cells with lovastatin, an inhibitor of p21(ras) signaling, greatly inhibited the accumulation of p53 induced by SIN-1. Northern blot and immunofluorescence analyses revealed that primary neural cells treated with SIN-1 had increased levels of p19 alternate reading frame (p19(ARF)) mRNA and protein, which is induced by MAPK and stabilizes the p53 protein. Our findings clearly show that the p21(ras)-MAPK-p19(ARF) pathway has an essential role in p53-dependent apoptosis triggered by peroxynitrite in neural cells.