RefZ and Noc act synthetically to prevent aberrant divisions during Bacillus subtilis sporulation

During sporulation, Bacillus subtilis undergoes an atypical cell division that requires overriding mechanisms which protect chromosomes from damage and ensure inheritance by daughter cells. Instead of assembling between segregated chromosomes at midcell, the FtsZ-ring (Z-ring) coalesces polarly, directing division over one chromosome. The DNA-binding protein RefZ facilitates the timely assembly of polar Z-rings and partially defines the region of chromosome initially captured in the forespore. RefZ binds to motifs (RBMs) located proximal to the origin of replication (oriC). Although refZ and the RBMs are conserved across the Bacillus genus, a refZ deletion mutant sporulates with wildtype efficiency, so the functional significance of RefZ during sporulation remains unclear. To further investigate RefZ function, we performed a candidate-based screen for synthetic sporulation defects by combining ∆refZ with deletions of genes previously implicated in FtsZ regulation and/or chromosome capture. Combining ∆refZ with deletions of ezrA, sepF, parA, or minD did not detectably affect sporulation. In contrast, a ∆refZ ∆noc mutant exhibited a sporulation defect, revealing a genetic interaction between RefZ and Noc. Using reporters of sporulation progression, we determined the ∆refZ ∆noc mutant exhibited sporulation delays after Spo0A activation but prior to late sporulation, with a subset of cells failing to divide polarly or activate the first forespore-specific sigma factor, SigF. The ∆refZ ∆noc mutant also exhibited extensive dysregulation of cell division, producing cells with extra, misplaced, or otherwise aberrant septa. Our results reveal a previously unknown epistatic relationship that suggests refZ and noc contribute synthetically to regulating cell division and supporting spore development.

HMGB1 signaling phosphorylates Ku70 and impairs DNA damage repair in Alzheimer’s disease pathology

DNA damage is increased in Alzheimer’s disease (AD), while the underlying mechanisms are unknown. Here, we employ comprehensive phosphoproteome analysis, and identify abnormal phosphorylation of 70 kDa subunit of Ku antigen (Ku70) at Ser77/78, which prevents Ku70-DNA interaction, in human AD postmortem brains. The abnormal phosphorylation inhibits accumulation of Ku70 to the foci of DNA double strand break (DSB), impairs DNA damage repair and eventually causes transcriptional repression-induced atypical cell death (TRIAD). Cells under TRIAD necrosis reveal senescence phenotypes. Extracellular high mobility group box 1 (HMGB1) protein, which is released from necrotic or hyper-activated neurons in AD, binds to toll-like receptor 4 (TLR4) of neighboring neurons, and activates protein kinase C alpha (PKCα) that executes Ku70 phosphorylation at Ser77/78. Administration of human monoclonal anti-HMGB1 antibody to post-symptomatic AD model mice decreases neuronal DSBs, suppresses secondary TRIAD necrosis of neurons, prevents escalation of neurodegeneration, and ameliorates cognitive symptoms. TRIAD shares multiple features with senescence. These results discover the HMGB1-Ku70 axis that accounts for the increase of neuronal DNA damage and secondary enhancement of TRIAD, the cell death phenotype of senescence, in AD.

Differential Diagnosis of Lipoma and Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma by Cytological Analysis

Background: Adipocytic tumors are the most common soft tissue tumors, with lipomas and atypical lipomatous tumor/well-differentiated liposarcomas (ALT/WDL) comprising the majority of cases. Preoperative differential diagnosis of lipoma or ALT/WDL can provide important information for decisions regarding treatment. We evaluated the cytological findings of 20 cases of lipoma and ALT/WDL.Methods: Fluorescence in situ hybridization (FISH) was performed on formalin-fixed paraffin-embedded specimens (FFPE) to examine mouse double minute 2 homolog (MDM2) amplification in all cases. Tissue samples were collected from the center of the surgical materials, stained with Papanicolaou, and evaluated for 12 cytological parameters by six cytotechnologists.Results: The findings regarding large atypical cells, multinucleated cells, and nuclear pleomorphism were highly concordant among the cytotechnologists and were associated with MDM2 amplification. Large atypical cells, considered a highly specific feature of ALT/WDL, were not observed in the lipoma cases. However, the sensitivity of the large atypical cell findings was not high (67%), and therefore, comprehensive evaluation of multinucleated cells and pleomorphism is crucial for predicting the diagnosis of ALT/WDL. FISH of MDM2 on Papanicolaou-stained specimens was performed in four cases. In two cases, the results were similar to those of MDM2 FISH performed on FFPE sections and were reproducible, whereas in two other cases, the signal could not be evaluated because of the strong background coloration. Conclusions: Cytology specimens may be useful for preoperative diagnosis of adipocytic tumors, particularly if the FISH conditions for Papanicolaou-stained specimens and the detection accuracy of MDM2 amplification can be improved.

DNA damage in embryonic neural stem cell determines FTLDs’ fate via early-stage neuronal necrosis

The early-stage pathologies of frontotemporal lobal degeneration (FTLD) remain largely unknown. In VCPT262A-KI mice carrying VCP gene mutation linked to FTLD, insufficient DNA damage repair in neural stem/progenitor cells (NSCs) activated DNA-PK and CDK1 that disabled MCM3 essential for the G1/S cell cycle transition. Abnormal neural exit produced neurons carrying over unrepaired DNA damage and induced early-stage transcriptional repression-induced atypical cell death (TRIAD) necrosis accompanied by the specific markers pSer46-MARCKS and YAP. In utero gene therapy expressing normal VCP or non-phosphorylated mutant MCM3 rescued DNA damage, neuronal necrosis, cognitive function, and TDP43 aggregation in adult neurons of VCPT262A-KI mice, whereas similar therapy in adulthood was less effective. The similar early-stage neuronal necrosis was detected in PGRNR504X-KI, CHMP2BQ165X-KI, and TDPN267S-KI mice, and blocked by embryonic treatment with AAV–non-phospho-MCM3. Moreover, YAP-dependent necrosis occurred in neurons of human FTLD patients, and consistently pSer46-MARCKS was increased in cerebrospinal fluid (CSF) and serum of these patients. Collectively, developmental stress followed by early-stage neuronal necrosis is a potential target for therapeutics and one of the earliest general biomarkers for FTLD.

NODULAR SCLEROSIS HOGDKINS LYMPHOMA GRADE 2 MIMICKING ANAPLASTIC LARGE CELL LYMPHOMA - A CASE REPORT

INTRODUCTION: Hodgkin's lymphoma (HL) is a lymphoproliferative neoplasm constituting less than 1% of all neoplasms. It has been categorized into- nodular lymphocyte predominant HL and classical type with subtypeslymphocyte rich, lymphocyte depleted, nodular sclerosis and mixed cellularity. Nodular sclerosis Hodgkin's lymphoma (NSHL) is difcult to diagnose on FNA because of the lack of Reed Sternberg (RS) cells, low cellularity and difculty in identifying the counterpart of lacunar cells. CASE A 16-year-old female presented with anterior chest wall swelling si REPORT: nce 6 months measuring 5x4cm along with incidentally noted cervical lymph nodes measuring 2x2cm and 1x1cm. On examination, multiple papular skin lesions were observed. FNAC smears from cervical lymph node showed high cellularity, with sheets of binucleated and multinucleated cells having multiple nucleoli, some showing pale bluish abundant cytoplasm whereas others showing dense cytoplasm; in a background of reactive lymphoid population with few neutrophils. Few giant cells showed hyperchromatic nuclei. Abnormal mitosis seen. No typical RS cell was seen. Peripheral blood smear showed neutrophilic leukocytosis with no atypical cell. Possibility of NSHL was considered and biopsy advised to rule out ALCL. Histological sections showed near total effacement of lymph node architecture by nodules separated by broad brotic bands. These nodules exhibit proliferating lymphocytes with clustered lacunar cells along with some mononucleate, binucleate and multinucleated cells. Prominent mitotic activity, angiogenesis, focal micro abscesses were noted. Immunohistochemistry showed CD 15+ and CD 30+ expression in the giant cells, conrming diagnosis of NSHL grade 2. NSHL poses a cytological diagnostic dilemma specially in abse CONCLUSION: nce of sclerosis on FNA, making histological examination and IHC mandatory

A rare case of primary cutaneous diffuse large B cell lymphoma, leg type with metastasis

<p class="abstract">Primary cutaneous diffuse large B cell lymphoma, leg type (PCDLBCL-LT) is a rare and aggressive type of primary cutaneous B cell lymphoma (PCBCL), which represents 10-20% cases of PCBCL. It has a 40-50% recurrence rate and 5 year survival rate of 50%. Here, we present a case of an 86 year old female who presented to us with complaints of slightly tender annular plaques with an oedematous base present over bilateral lower limbs and pitting oedema. Histopathological examination from the annular lesion showed normal epidermis, grenz zone and a dense lymphoid infiltrate involving almost the entire dermis. Immunohistochemistry confirmed histological findings, atypical cell were positive for CD20 and MUM1 protein with focal expression of BCL 6 which is rare. Based on the above findings, we made a diagnosis of diffuse large B cell lymphoma-leg type and started her on palliative radiotherapy. As PCBCL-LT is rare and aggressive lymphoma, we present this case to review literature and summarise its clinical features.</p>

CLINICAL AND HISTOPATHOLOGICAL CORRELATION IN TUBERCULOSIS OF SPINE BIOPSIES

ABSTRACT: BACKGROUND & OBJECTIVE: The tuberculosis (TB) of the spine is causing permanent deformities since long time. Earliest most possible accurate diagnosis is required to treat either TB or to exclude other lesions to avoid permanent disability. METHODOLOGY: This is a descriptive study conducted at pathology department of Lahore Medical & Dental College (LM&DC), Lahore from January 2017 to December 2019. All the spine biopsies received in Pathology department were included in the study irrespective of age and sex. Each biopsy was grossly and microscopically examined and reported by a histopathologist. RESULTS: Out of 386 specimens received, 189 (48.9%) were clinically diagnosed as tuberculosis. Out of these 189 cases, 127 were confirmed on histopathological examination showing clinicopathological correlations in 67.19 % of cases. The rest 62 (32.80%) of the cases were reported as chronic non specific inflammation (38), degenerative changes (11), metastatic tumor (04), and atypical cell infiltrate (02), plasma cell neoplasm (01), Non Hodgkin Lymphoma (01) and other lesions (05) which all were benign. Out of the total 386 spine biopsies, 154 (39.89 %) were histopathologically proven for tuberculosis. From these 154 histologically proven cases, 127 were clinically suspected cases of Tuberculosis. No clinical diagnosis was provided in 02 patients. The rest of 25 patients were clinically labeled as pathological lesion without specific diagnosis. CONCLUSION: Histopathology should be considered as the most reliable tool for spinal tuberculosis to minimize permanent disability associated with wrong management based on potentially erroneous clinical diagnosis.

Atypical cells parameter in Sysmex UN automated urine analyzer: feedback from the field

Background “Atypical cells” parameter in automated urinalysis has recently been introduced. An instrument capable of measuring quantitative and qualitative features of nuclear and cytoplasmic properties of a cell has the potential to detect cellular atypia. Instruments using flow cytometry have been detecting atypical cells in blood for a long time; yet instruments using the same methodology very lately developed this parameter in urinalysis. Materials and methods Samples with an atypical cells value higher than 1 atypical cell/µL were included in the study. Besides automated urinalysis, every sample was reflexed to modular unit for digital imaging. The remainder of each sample was stained with Sternheimer dye and examined manually under a light microscope. Results 50 samples with higher than1 atypical cell/µL result were included in the study. Patients were composed of 43 females (86 %) and 7 males (14 %). The mean age was 47.12 ± 19.45 years. The median atypical cells value was 1.8/µL (95 % range 1.5–2.4/µL). Manual microscopic evaluation of the 50 samples showed atypical cells in 1 sample. The patient had papillary lesions on cystoscopy and pathology report informed a high grade urothelial carcinoma. Other 49 samples were negative for atypical cells in manual microscopy. They were crowded samples with leucocytes and squamous epithelial cells. Conclusions The positive case provided evidence for Sysmex UN’s capability to detect atypical cells in urine. The negative cases presented clues that probable vulvovaginal contamination and crowded specimens could be deceptive for Sysmex UN in this particular parameter.

Alternative Pathways of IL-1 Activation, and Its Role in Health and Disease

Cytokines activate or inhibit immune cell behavior and are thus integral to all immune responses. IL-1α and IL-1β are powerful apical cytokines that instigate multiple downstream processes to affect both innate and adaptive immunity. Multiple studies show that IL-1β is typically activated in macrophages after inflammasome sensing of infection or danger, leading to caspase-1 processing of IL-1β and its release. However, many alternative mechanisms activate IL-1α and IL-1β in atypical cell types, and IL-1 function is also important for homeostatic processes that maintain a physiological state. This review focuses on the less studied, yet arguably more interesting biology of IL-1. We detail the production by, and effects of IL-1 on specific innate and adaptive immune cells, report how IL-1 is required for barrier function at multiple sites, and discuss how perturbation of IL-1 pathways can drive disease. Thus, although IL-1 is primarily studied for driving inflammation after release from macrophages, it is clear that it has a multifaceted role that extends far beyond this, with various unconventional effects of IL-1 vital for health. However, much is still unknown, and a detailed understanding of cell-type and context-dependent actions of IL-1 is required to truly understand this enigmatic cytokine, and safely deploy therapeutics for the betterment of human health.