Multinucleated Research Articles

Isolated central nervous system lymphomatoid granulomatosis in an older adult patient with systematic lupus erythematosus: A case report.

Lymphomatoid granulomatosis (LYG) is a rare, T-cell-rich Epstein-Barr virus (EBV)-positive B-cell lymphoproliferative systemic disease. Only a few cases of LYG have been described in patients with autoimmune disorders, with only one case described in a patient with systemic lupus erythematosus (SLE). However, no cases of isolated central nervous system (CNS)-LYG have been reported in patients with autoimmune diseases. Since isolated CNS involvement is rare, its clinicopathological features remain incompletely understood. Herein, we report about an 85-year-old Japanese woman who was diagnosed with SLE 26 years ago and was stable and maintained on prednisone (5 mg/day) for 20 years. Twenty-six days before admission, she developed cognitive dysfunction. Brain magnetic resonance imaging (MRI) revealed multiple nodular lesions with ring-like enhancements seen on gadolinium-enhanced T1-weighted imaging. A brain biopsy was performed on the right frontal lobe lesion. Pathological findings revealed T-cell infiltration surrounding the blood vessels with fibrin deposition, a few multinucleated cells, and large atypical cells with prominent nucleoli. Large atypical cells positive for CD20 and EBV-encoded RNA (EBER) were seen at a density of >100 cells per high-power field. Based on laboratory testing, imaging, and pathology findings, the patient was diagnosed with grade III LYG. Treatment with tirabrutinib (480 mg once daily) was started. The patient achieved clinical response to treatment, as evidenced by improved mental status. In patients with SLE who present with multiple nodular or ring-like lesions on brain MRI, brain biopsy with histological diagnosis is crucial for the exclusion of CNS-LYG.

Chemical transformation of the multibudding yeast, Aureobasidium pullulans.

Aureobasidium pullulans is a ubiquitous polymorphic black yeast with industrial and agricultural applications. It has recently gained attention amongst cell biologists for its unconventional mode of proliferation in which multinucleate yeast cells make multiple buds within a single cell cycle. Here, we combine a chemical transformation method with genome-targeted homologous recombination to yield ∼60 transformants/μg of DNA in just 3 days. This protocol is simple, inexpensive, and requires no specialized equipment. We also describe vectors with codon-optimized green and red fluorescent proteins for A. pullulans and use these tools to explore novel cell biology. Quantitative imaging of a strain expressing cytosolic and nuclear markers showed that although the nuclear number varies considerably among cells of similar volume, total nuclear volume scales with cell volume over an impressive 70-fold size range. The protocols and tools described here expand the toolkit for A. pullulans biologists and will help researchers address the many other puzzles posed by this polyextremotolerant and morphologically plastic organism.

THIN AND ULTRATHIN STRUCTURE OF ENVELOPES OF STEPHANOSTOMUM BACCATUM (TREMATODA: ACANTHOCOLPIDAE) METACERCARIAE IN YELLOWFIN SOLE, LIMANDA ASPERA.

The structure of the envelopes (capsule and cyst) surrounding metacercariae of Stephanostomum baccatum (Nicoll, 1907) in the second intermediate host, the yellowfin sole Limanda aspera (Pallas 1814), is examined with the methods of light and transmission electron microscopy. The cyst, presumably formed by secretions of the metacercarial tegument, consists of 2 layers: the outer, very thin layer of an electron-dense, finely granular substance and the inner layer composed of loose material of a moderate electron density that includes dense bodies varying in size, shape, and localization. The capsule, formed by the host's cells, is also organized into 2 distinct layers. The inner layer of the capsule is loose, consisting of evenly spaced debris of degenerated cells and lipid droplets with inclusions of intact macrophages between them. The outer layer of the capsule consists of parallel rows of cells arranged around the parasite, with fibroblasts and macrophages being dominant types and granulocytes and lymphocytes found in smaller numbers. Aggregations of collagen fibers are located in narrow spaces between the cells. The number of lipid droplets in the outer layer is significantly smaller than in the inner layer. The capsules formed around the examined trematodes have several structural features that distinguish them from those of S. baccatum and Stephanostomum sp. metacercariae recovered from other fishes of the family Pleuronectidae. The major morphological features of such capsules are the lack of epithelioid or giant multinucleated cells and the presence of numerous lipid droplets. Investigating the structural details of the envelopes surrounding metacercariae in trematodes, as well as other helminths, contributes to our scientific understanding of parasite biology, which can, in turn, have broader implications for understanding host-parasite interactions and evolutionary biology.

Spatial multi-omics in whole skeletal muscle reveals complex tissue architecture

Myofibers are large multinucleated cells that have long thought to have a rather simple organization. Single-nucleus transcriptomics, spatial transcriptomics and spatial metabolomics analysis have revealed distinct transcription profiles in myonuclei related to myofiber type. However, the use of local tissue collection or dissociation methods have obscured the spatial organization. To elucidate the full tissue architecture, we combine two spatial omics, RNA tomography and mass spectrometry imaging. This enables us to map the spatial transcriptomic, metabolomic and lipidomic organization of the whole murine tibialis anterior muscle. Our findings on heterogeneity in fiber type proportions are validated with multiplexed immunofluorescence staining in tibialis anterior, extensor digitorum longus and soleus. Our results demonstrate unexpectedly strong regionalization of gene expression, metabolic differences and variable myofiber type proportion along the proximal-distal axis. These new insights in whole-tissue level organization reconcile sometimes conflicting results coming from previous studies relying on local sampling methods.

Compound K Promotes Megakaryocytic Differentiation by NLRP3 Inflammasome Activation.

Platelets are essential blood components that maintain hemostasis, prevent excessive bleeding, and facilitate wound healing. Reduced platelet counts are implicated in various diseases, including leukemia, hepatitis, cancer, and Alzheimer's disease. Enhancing megakaryocytic differentiation is a promising strategy to increase platelet production. Compound K (CK), a major bioactive metabolite of ginsenosides from Panax ginseng, has demonstrated anti-cancer and neuroprotective properties. In this study, we investigated the effects of CK on megakaryocytic differentiation and apoptosis in chronic myeloid leukemia (CML) cell lines K562 and Meg-01. CK treatment significantly upregulated the mRNA expression of key megakaryocytic differentiation markers, including CD61, CD41, and CD42a, and promoted the formation of large, multinucleated cells in K562 cells. Additionally, flow cytometry analysis revealed that CK at 5 µM induced apoptosis, a critical process in thrombocytopoiesis, in both K562 and Meg-01 cells. RT2 Profiler PCR array analysis further identified a marked increase in the expression of genes associated with the activation of the NLRP3 inflammasome in CK-treated K562 and Meg-01 cells. This study is the first to demonstrate that CK promotes megakaryocytic differentiation and apoptosis through the activation of the ERK/EGR1 and NLRP3 inflammasome pathways. These findings suggest that CK may enhance platelet production, indicating its potential as a therapeutic candidate for platelet-related disorders and other associated diseases.

B-314 Utility of he4 in differential diagnosis of pleural effusions

Abstract Background The usefulness of tumor markers in the differential diagnosis of cancer in patients with pleural effusions (PE) remains controversial. Few studies have reported the measurement of human epididymal protein 4 (HE4) in pleural fluid. HE4 is a tumor marker associated with different types of cancer. An elevated serum concentration has been observed in ovarian and lung cancers. Other benign pathologies can increase HE4 levels, which can be detect with different laboratory tests identified with adenosine deaminase (ADA), C-reactive protein (CRP), % polynuclear cell count (%PMN) and glomerular filtration rate (GFR) can be used in order to detect possible false positives. The objective of this study was to assess the diagnostic usefulness of HE4 in malignant pleural effusions by comparing HE4 concentrations between benign and malignant samples, while considering the causes of HE4 false positives. Methods HE4, ADA, differential leukocyte count, CRP and GFR concentrations were determined in 238 pleural effusion samples. Diagnostic efficacy analysis using receiver operating curves (ROC) identified the ability of HE4 to detect malignancy, searching for cut-off points with 100% specificity. Results HE4 concentrations showed significant differences (P<0.01) between malignant (median 1065pmol/L) and benign (median 699pmol/L) pleural effusions. Significant differences (P<0.01) were found in HE4 concentrations for gynecological and lung cancer origin (median 7397 pmol/L and 5150 pmol/L respectively) and other malignant pleural effusions (median 1065 pmol/L). Patients with benign diseases with renal failure showed a higher HE4 concentration (median 964pmol/L) than in patients without these pathologies (median 696pmol/L) identified with GFR<30 mL/min. No differences were demonstrated in HE4 concentration levels using ADA, differential leukocyte count or CRP, so only glomerular filtration rate was considered cause of false positives. A sensitivity of 23% was obtained for HE4, with a cut-off point of 3050pmol/L and a specificity of 100% for the whole group. In the potential false positive group, the sensitivity of HE4 was 28% with a cutoff point of 3050 pmol/L with a specificity of 100%. In the group without potential false positives, we obtained a sensitivity of 30% with a specificity of 100% for a cutoff point of 1992pmol/L. When we used a specific cut-off point for each group, we obtained a sensitivity of 38% with a specificity of 100%. Conclusions HE4 levels are higher in malignant pleural effusions compared to other pathologies. HE4 levels allow the identification of malignant pleural effusions with moderate sensitivity and maximum specificity. HE4 levels can differentiate between tumors of gynecological or lung origin and others. Glomerular filtration rate (GFR<30 mL/min) was considered the main cause of false positives. If we identify possible false positives, we can use specific cut-offs and improve sensitivity up to 38% with maximum specificity compared to using a single cut-off for all effusions.

Herbal medicine Ninjinyoeito inhibits RANKL-induced osteoclast differentiation and bone resorption activity by regulating NF-κB and MAPK pathway

ObjectivesOsteoporosis is a systemic bone metabolism disorder characterized by decreased bone mass and strength. Osteoclasts (OCs) are giant multinucleated cells that regulate bone homeostasis by degrading bone matrix. Excessive OC differentiation and activity can lead to serious bone metabolic disorders including osteoporosis. Current treatments, including antiresorptive drugs, exert considerable adverse effects, including jaw osteonecrosis. Herbal medicines, such as Ninjinyoeito (NYT), may also offer efficacy, but with fewer adverse effects. In this study, we investigated NYT's effects on osteoclastogenesis. MethodsTartrate-resistant acid phosphatase (TRAP) staining and bone resorption assays were performed to examine NYT's effects on OC differentiation and function. OC-related gene expression at mRNA and protein levels was investigated to confirm NYT's inhibitory action against osteoclastogenesis. We also demonstrated involvement of signaling pathways mediated by IκBα and mitogen-activated protein kinases (MAPK) [extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38] and showed nuclear translocation of nuclear factor of activated T-cell cytoplasmic 1 (NFATc1) and nuclear factor kappa B (NF-κB) p65 during osteoclastogenesis. ResultsTRAP staining and bone resorption assays confirmed that NYT significantly inhibited OC differentiation and function. Western blot and RT-PCR results showed that NYT ameliorated osteoclastogenesis by suppressing mRNA and protein level expression of OC-related genes. Moreover, blots and immunocytochemistry (ICC) data clarified that NYT abrogates signaling pathways mediated by IκBα and MAPK (ERK, JNK, p38), and demonstrated nuclear translocation of NFATc1 and NF-κB p65 during OC differentiation. ConclusionsThese findings suggest NYT is an alternative therapeutic candidate for treating osteoporosis.

Targeting EZH2 attenuates the ferroptosis-mediated osteoblast–osteoclast imbalance in rheumatoid arthritis

ObjectiveThe enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) can regulate osteogenesis and osteoclastogenesis. This study aimed to further explore the effects of EZH2 modification on ferroptosis and the osteoblast–osteoclast balance in rheumatoid arthritis (RA) in vitro and in vivo. MethodsBone marrow mesenchymal stromal cells were transfected with EZH2 overexpression (oeEZH2) and EZH2 shRNA (shEZH2) plasmids with or without ferrostatin-1 (Fer-1) treatment and subjected to an osteoblast differentiation assay. The cells were then cocultured with bone marrow-derived macrophages and subjected to an osteoclast differentiation assay. Collagen-induced arthritis (CIA) mice were generated and injected with shEZH2 adeno-associated virus (AAV). ResultsOeEZH2 repressed osteoblast differentiation, as reflected by decreased ALP and Alizarin Red S staining and increased OPN, RUNX2, OPG and RANKL; however, shEZH2 had the opposite effects. Besides, oeEZH2 promoted osteoblast ferroptosis, as suggested by increased MDA, Fe2+, ROS, and PTGS2 but decreased GPX4 and SLC7A11; these effects could be attenuated by Fer-1 treatment. In contrast, shEZH2 ameliorated osteoblast ferroptosis. OeEZH2 subsequently increased osteoclast differentiation, as indicated by increased TRAP+ multinucleated cells, NFATC1, CTSK, and c-FOS; however, shEZH2 had the opposite effect, except that it did not regulate CTSK. In CIA mice, shEZH2 AAV decreased the clinical symptom score, histological score of cartilage, and systemic inflammation (TNF-α and IL-6) and repressed bone ferroptosis and restored the osteoblast–osteoclast balance to some extent, as reflected by immunohistochemical staining of related markers. ConclusionTargeting EZH2 attenuates the ferroptosis-mediated osteoblast–osteoclast imbalance in RA, revealing its potential as a treatment target.

Modeling the processes of transendothelial transport of LDL and macrophage migration

Atherosclerosis is a multifactorial process involving various pathological mechanisms: inflammation, lipoprotein modification, cholesterol accumulation, endothelial dysfunction, oxidative stress and formation of atherosclerotic plaque. The main participants in the development of this disease are endothelial cells, leukocytes and smooth muscle cells of intima. The adult endothelium contains heterogeneous cells, including typical endothelial cells (TEC) and giant multinucleated EC variants (MVEC). The process of passing molecules is called transendothelial transport (TET). The purpose of this work is to model the processes of TET of low-density lipoproteins (LDL) and monocyte migration using various EC variants. In the study, a human EC line (EA.hy926) was used. Multicore variants of EC (MVEC) were obtained by treating EC with a 50% solution of polyethylene glycol 6000. To study LDL transcytosis and monocyte migration, tablets with inserts (0.4 or 3.0 micron pore diameter, respectively) forming a two-level system were used. The LDL transmission rate was assessed by measuring the amount of cholesterol in the upper and lower chambers every 2, 5 and 24 hours. A modified Folch method was used to measure the amount of cholesterol. The cholesterol content was adjusted according to the total protein level in the well, measured by the Lowry method. The migration of macrophages was estimated by direct counting of cells. The content of internalized cholesterol in the MVEC was statistically significantly higher than in the EC. The rate of LDL transport did not differ. The rate of passage of the endothelial barrier formed by MVEC by macrophages was higher at points 2 and 5 hours. After 24 hours the number of migrated cells did not differ. The rate of transendothelial transport for typical and multinucleated variants of EC did not statistically differ. Although the presence of MBEC does not affect the transport of lipoproteins into the subendothelial layer, the fact that multinucleated cells accumulate lipid droplets more actively than typical ECS may indicate an important role in the pathogenesis of atherosclerosis. The rate of macrophage migration after 2 and 5 hours was higher for MVEC than for TEC, whereas immature macrophages did not migrate through the endothelial barrier for 24 hours.

Disseminated pleomorphic rhabdomyosarcoma in a horse.

An 8-y-old National Show Horse mare was presented for evaluation of pneumonia and laminitis. Harsh bronchovesicular sounds were auscultated throughout both lung fields, and the mare had signs of moderately painful laminitis. Thoracic ultrasonography revealed lung consolidation throughout the dorsal aspect of both lungs, and radiography revealed an extensive diffuse-to-patchy bronchointerstitial lung pattern. The mare's clinical condition rapidly deteriorated, and euthanasia was elected. On postmortem examination, the lungs, omentum, spleen, liver, adrenal glands, kidneys, and femur contained 0.5-2.5-cm, firm, tan nodules. Histologically, the lungs, spleen, liver, kidneys, adrenal glands, omentum, left eye, and femur were infiltrated by bundles and nests of pleomorphic polygonal-to-spindloid cells intermixed with frequent multinucleate cells. Lymphatic vessels in the affected tissues were frequently distended with tumor emboli. Neoplastic cells were diffusely positive for vimentin, desmin, sarcomeric actin, myoblastic differentiation protein 1, and myogenin, supportive of the diagnosis of rhabdomyosarcoma (RMS), which is a rare neoplasm in horses. Cross-striations were not evident with H&E or phosphotungstic acid-hematoxylin stains. Markedly pleomorphic neoplastic cells, multinucleate cells, and lack of cross-striations suggested the subclassification of pleomorphic RMS.

The Autonomous Fusion Activity of Human Cytomegalovirus Glycoprotein B Is Regulated by Its Carboxy-Terminal Domain.

The human cytomegalovirus (HCMV) glycoprotein B (gB) is the viral fusogen required for entry into cells and for direct cell-to-cell spread of the virus. We have previously demonstrated that the exchange of the carboxy-terminal domain (CTD) of gB for the CTD of the structurally related fusion protein G of the vesicular stomatitis virus (VSV-G) resulted in an intrinsically fusion-active gB variant (gB/VSV-G). In this present study, we employed a dual split protein (DSP)-based cell fusion assay to further characterize the determinants of fusion activity in the CTD of gB. We generated a comprehensive library of gB CTD truncation mutants and identified two mutants, gB-787 and gB-807, which were fusion-competent and induced the formation of multinucleated cell syncytia in the absence of other HCMV proteins. Structural modeling coupled with site-directed mutagenesis revealed that gB fusion activity is primarily mediated by the CTD helix 2, and secondarily by the recruitment of cellular SH2/WW-domain-containing proteins. The fusion activity of gB-807 was inhibited by gB-specific monoclonal antibodies (MAbs) targeting the antigenic domains AD-1 to AD-5 within the ectodomain and not restricted to MAbs directed against AD-4 and AD-5 as observed for gB/VSV-G. This finding suggested a differential regulation of the fusion-active conformational state of both gB variants. Collectively, our findings underscore a pivotal role of the CTD in regulating the fusogenicity of HCMV gB, with important implications for understanding the conformations of gB that facilitate membrane fusion, including antigenic structures that could be targeted by antibodies to block this essential step in HCMV infection.

Non-canonical olfactory pathway activation induces cell fusion of cervical cancer cells

Multinucleation occurs in various types of advanced cancers and contributes to their malignant characteristics, including anticancer drug resistance. Therefore, inhibiting multinucleation can improve cancer prognosis; however, the molecular mechanisms underlying multinucleation remain elusive. Here, we introduced a genetic mutation in cervical cancer cells to induce cell fusion-mediated multinucleation. The olfactory receptor OR1N2 was heterozygously mutated in these fused cells; the same OR1N2 mutation was detected in multinucleated cells from clinical cervical cancer specimens. The mutation-induced structural change in the OR1N2 protein activated protein kinase A (PKA), which, in turn, mediated the non-canonical olfactory pathway. PKA phosphorylated and activated furin protease, resulting in the cleavage of the fusogenic protein syncytin-1. Because this cleaved form of syncytin-1, processed by furin, participates in cell fusion, furin inhibitors could suppress multinucleation and reduce surviving cell numbers after anticancer drug treatment. The improved anticancer drug efficacy indicates a promising therapeutic approach for advanced cervical cancers.

Moesin controls cell-cell fusion and osteoclast function.

Cell-cell fusion is an evolutionarily conserved process that is essential for many functions, including fertilisation and the formation of placenta, muscle and osteoclasts, multinucleated cells that are unique in their ability to resorb bone. The mechanisms of osteoclast multinucleation involve dynamic interactions between the actin cytoskeleton and the plasma membrane that are still poorly characterized. Here, we found that moesin, a cytoskeletal linker protein member of the Ezrin/Radixin/Moesin (ERM) protein family, is activated during osteoclast maturation and plays an instrumental role in both osteoclast fusion and function. In mouse and human osteoclast precursors, moesin inhibition favors their ability to fuse into multinucleated osteoclasts. Accordingly, we demonstrated that moesin depletion decreases membrane-to-cortex attachment and enhances the formation of tunneling nanotubes (TNTs), F-actin-based intercellular bridges that we reveal here to trigger cell-cell fusion. Moesin also controls HIV-1- and inflammation-induced cell fusion. In addition, moesin regulates the formation of the sealing zone, the adhesive structure determining osteoclast bone resorption area, and thus controls bone degradation, via a β3-integrin/RhoA/SLK pathway. Supporting our results, moesin - deficient mice present a reduced density of trabecular bones and increased osteoclast abundance and activity. These findings provide a better understanding of the regulation of cell-cell fusion and osteoclast biology, opening new opportunities to specifically target osteoclast activity in bone disease therapy.

SREBP2 restricts osteoclast differentiation and activity by regulating IRF7 and limits inflammatory bone erosion

Osteoclasts are multinucleated bone-resorbing cells, and their formation is tightly regulated to prevent excessive bone loss. However, the mechanisms by which osteoclast formation is restricted remain incompletely determined. Here, we found that sterol regulatory element binding protein 2 (SREBP2) functions as a negative regulator of osteoclast formation and inflammatory bone loss. Cholesterols and SREBP2, a key transcription factor for cholesterol biosynthesis, increased in the late phase of osteoclastogenesis. The ablation of SREBP2 in myeloid cells resulted in increased in vivo and in vitro osteoclastogenesis, leading to low bone mass. Moreover, deletion of SREBP2 accelerated inflammatory bone destruction in murine inflammatory osteolysis and arthritis models. SREBP2-mediated regulation of osteoclastogenesis is independent of its canonical function in cholesterol biosynthesis but is mediated, in part, by its downstream target, interferon regulatory factor 7 (IRF7). Taken together, our study highlights a previously undescribed role of the SREBP2-IRF7 regulatory circuit as a negative feedback loop in osteoclast differentiation and represents a novel mechanism to restrain pathological bone destruction.

Development of a skeletal muscle sheet with direct reprogramming-induced myoblasts on a nanogel-cross-linked porous freeze-dried gel scaffold in a mouse gastroschisis model.

In this study, we attempted to create skeletal muscle sheets made of directly converted myoblasts (dMBs) with a nanogel scaffold on a biosheet using a mouse gastroschisis model. dMBs were prepared by the co-transfection of MYOD1 and MYCL into human fibroblasts. Silicon tubes were implanted under the skin of NOG/SCID mice, and biosheets were formed. The nanogel was a nanoscale hydrogel based on cholesterol-modified pullulan, and a NanoClip-FD gel was prepared by freeze-drying the nanogel. 7mm in length was created in the abdominal wall of NOG/SCID mice as a mouse gastroschisis model. Matrigel or NanoCliP-FD gel seeded with dMBs was placed on the biosheet and implanted on the model mice. Fourteen days after surgery, dMBs with Matrigel showed a small amount of coarse aggregations of muscle-like cells. In contrast, dMBs with NanoCliP-FD gel showed multinucleated muscle-like cells, which were expressed as desmin and myogenin by fluorescent immunostaining. Nanogels have a porous structure and are useful as scaffolds for tissue regeneration by supplying oxygen and nutrients supply to the cells. Combining dMBs and nanogels on the biosheets resulted in the differentiation and engraftment of skeletal muscle, suggesting the possibility of developing skeletal muscle sheets derived from autologous cells and tissues.

Loss of PRICKLE1 leads to abnormal endometrial epithelial architecture, decreased embryo implantation, and reduced fertility in mice.

Conservative cell division is essential to maintain apical-basal polarity and proper epithelial function in the uterus. Wnt/ Planar cell polarity signaling molecules are hypothesized to provide the spatial cues to organize unicellular, 2-dimensional sheet of epithelium in a plane orthogonal to the apical-basal polarity. Conditional ablation of Prickle1 , a crucial Wnt/ PCP gene, in mouse uterine epithelium results in aberrant expression of epithelial cadherin, altered plane of cell division, incomplete cytokinesis leading to binucleated/ multinucleated cells, epithelial - mesenchymal transition, and defective implantation. Role of Prickle1 in maintaining symmetric uterine epithelial cell division and tissue architecture is unique among Wnt/PCP genes, including previously described mouse models for Vangl2, Ror2, and Wnt5a . Classification: Biological Sciences (Major) Cell Biology (Minor), Physiology (Minor).

Plasma exchange-sensitive syncytial glomerulopathy in a kidney transplant patient.

Microvascular inflammation (MVI), defined as the presence of glomerulitis and/or peritubular capillaritis, is the key histological lesion of anti-HLA donor-specific antibodies (DSA)-related antibody mediated rejection, but recently other possible mechanisms of MVI have emerged. However, except for peritubular capillary C4d deposition that is more frequently observed in the presence of anti-HLA-DSA, histological features are similar regardless of MVI origin. Therefore, accurately describing patterns of MVI may help differentiate etiologies and drive therapeutic choices. We describe the case of a kidney transplant recipient (primary nephropathy: autosomal dominant polycystic kidney disease) who underwent kidney biopsy for worsening renal function and new onset hypertension. Histologic findings showed severe microvascular inflammation with intense glomerulitis and presence of intracapillary multinucleated cells, positive on immunostaining for endothelial marker ETS-related gene (ERG). Focal intense peritubular capillaritis and early glomerular basement membrane reduplication, C4d negative, were observed, consistent with early chronic active ABMR. HLA-DSA were absent, but high level of anti-angiotensin II type-1 receptor (AT1R) antibodies (Ab) were detected (78 U/L, normal levels < 10 U/L). Two subsequent biopsies showed intense microvascular inflammation with diffuse peritubular capillaritis, and multinucleated, ERG-positive, endothelial cells were still seen in glomerular capillary loops. The patient was started on angiotensin receptor blockers (ARBs) and plasma exchange (PEX) sessions obtaining normalization of blood pressure and AT1R Ab and proteinuria reduction, but, after subsequent liver transplant, rituximab therapy failed to maintain remission and the patient remained PEX-dependent.

Urothelial Carcinoma with Trophoblastic Differentiation-A Report with Review.

Urothelial carcinoma with trophoblastic differentiation is a rare type of urothelial carcinoma that poses a diagnostic challenge. A 50-year-old man presented with hematuria for 4 months duration. Ultrasonography examination showed polypoidal lesions along the right lateral wall and near the right vesicoureteric junction of the urinary bladder. The transurethral resection of the bladder tumor (TURBT) specimen showed marked necrosis and urothelial tumor cells arranged in nests, sheets, and papillae, admixed with multinucleated large cells. Deep muscle and extensive lymphovascular invasion were noted. The tumor cells were diffuse immunopositive for GATA3 and focal positive for p63 and SALL4. Large multinucleated tumor cells were immunopositive for β-hCG, GATA3, inhibin-α, and PLAP, focally positive for SALL4 while negative for p63. The patient denied further treatment and succumbed to the disease after 8 months of the TURBT procedure. We report a rare invasive urothelial carcinoma with trophoblastic differentiation and discuss the differential diagnosis and literature review.

Analysis of the rate of transcytosis in endothelial and giant multinucleated cells

Analysis of the rate of transcytosis in endothelial and giant multinucleated cells

B-type plexins regulate mitosis via RanGTPase.

Aberrant mitosis can result in aneuploidy and cancer. The small GTPase, Ran, is a key regulator of mitosis. B-type Plexins regulate Ran activity by acting as RanGTPase activating proteins (GAPs) and have been implicated in cancer progression. However, whether B-type plexins have a role in mitosis has not so far been investigated. We show here that PlexinB1 functions in the control of mitosis. Depletion of PlexinB1 affects mitotic spindle assembly, significantly delaying anaphase. This leads to mitotic catastrophe in some cells, and prolonged application of the spindle assembly checkpoint. PlexinB1 depletion also promoted acentrosomal microtubule nucleation and defects in spindle pole refocussing and increased the number of cells with multipolar or aberrant mitotic spindles. An increase in lagging chromosomes or chromosomal bridges at anaphase was also found upon PlexinB1 depletion. PlexinB1 localises to the mitotic spindle in dividing cells. The mitotic defects observed upon PlexinB1 depletion were rescued by an RCC1 inhibitor, indicating that PlexinB1 signals, via Ran, to affect mitosis. These errors in mitosis generated multinucleate cells, and nuclei of altered morphology and abnormal karyotype. Furthermore, Semaphorin4D-treatment increased the percentage of cells with micronuclei, precursors of chromothripsis. Implications: Defects in B-type plexins may contribute to the well-established role of plexins in cancer progression by inducing chromosomal instability.