Integration of Flow Cytometry and Computational Analysis to Dissect the Epidermal Cellular Subsets in Keloids that Correlate with Recurrence.

Keloid disease is a benign skin disease that does not have an effective therapy. More and more research shows that epidermal abnormalities are involved in keloid pathogenesis. Little is known about the relationship between the abnormal epidermal immunophenotype and clinical outcome. Nine-color flow cytometry with computational analysis was performed to detect the altered cellular subpopulation distribution in keloid lesions. Receiver operating characteristic curves were drawn to compare predictive ability between the alteration of cell subgroup frequency and the Vancouver Scar Scale. The frequency of CD49fhi/CD29+/TLR7+ cellular subsets increased in the keloid epidermis compared with that in the healthy control. CD49fmid-hi/CD29+/TLR7+/CD24+ cellular subpopulation level was increased significantly in keloids, whereas CD49flo-mid/CD29‒/TLR7‒/CD24‒ cellular subpopulation frequency was decreased. The CD49flo/CD29‒/TLR7‒/CD24+/CD117+ cellular subpopulation showed an increased frequency during recurrence with a sensitivity of 66.7% and specificity of 91.7%. The area under the curve was 0.806 for cellular subpopulation analysis, which was higher than the area under the curve for the Vancouver Scar Scale (0.583). The alteration of keloid epidermal subpopulation frequency is related to recurrence, which will provide an optional predictive marker for keloid recurrence and a potential target subset for investigating the generation of keloid.

A global live cell barcoding approach for multiplexed mass cytometry profiling of mouse tumors.

With the advent of cancer immunology, mass cytometry has been increasingly employed to characterize the responses to cancer therapies and the tumor microenvironment (TME). One of its most notable applications is efficient multiplexing of samples into batches by dedicating a number of metal isotope channels to barcodes, enabling robust data acquisition and analysis. Barcoding is most effective when markers are present in all cells of interest. While CD45 has been shown to be a reliable marker for barcoding all immune cells in a given sample, a strategy to reliably barcode mouse cancer cells has not been demonstrated. To this end, we identified CD29 and CD98 as markers widely expressed by commonly used mouse cancer cell lines. We conjugated anti-CD29 and anti-CD98 antibodies to cadmium or indium metals and validated their utility in 10-plex barcoding of live cells. Finally, we established a potentially novel barcoding system incorporating the combination of CD29, CD98, and CD45 to multiplex 10 tumors from s.c. MC38 and KPC tumor models, while successfully recapitulating the known contrast in the PD1-PDL1 axis between the 2 models. The ability to barcode tumor cells along with immune cells empowers the interrogation of the tumor-immune interactions in mouse TME studies.

The effect of ionising radiation on the phenotype of bone marrow-derived extracellular vesicles.

OBJECTIVES: Ionising radiation-induced alterations affecting intercellular communication in the bone marrow (BM) contribute to the development of haematological pathologies. Extracellular vesicles (EVs), which are membrane-coated particles released by cells, have important roles in intercellular signalling in the BM. Our objective was to investigate the effects of ionising radiation on the phenotype of BM-derived EVs of total-body irradiated mice. METHODS: CBA mice were irradiated with 0.1 Gy or 3 Gy X-rays. BM was isolated from the femur and tibia 24 h after irradiation. EVs were isolated from the BM supernatant. The phenotype of BM cells and EVs was analysed by flow cytometry. RESULTS: The mean size of BM-derived EVs was below 300 nm and was not altered by ionising radiation. Their phenotype was very heterogeneous with EVs carrying either CD29 or CD44 integrins representing the major fraction. High-dose ionising radiation induced a strong rearrangement in the pool of BM-derived EVs which were markedly different from BM cell pool changes. The proportion of CD29 and CD44 integrin-harbouring EVs significantly decreased and the relative proportion of EVs with haematopoietic stem cell or lymphoid progenitor markers increased. Low-dose irradiation had limited effect on EV secretion. CONCLUSIONS: Ionising radiation induced selective changes in the secretion of EVs by the different BM cell subpopulations. ADVANCES IN KNOWLEDGE: The novelty of the paper consists of performing a detailed phenotyping of BM-derived EVs after in vivo irradiation of mice.

[Relationship between supernatant cytokines and expression of markers of epitelial-mesenchymal transition of invasive breast carcinoma of non-specific lymphynosis type]. / Vzaimosviaz' mezhdu tsitokinami supernatantov i ékspressiei markerov épitelial'no-mezenkhimal'nogo perekhoda bioptatov invazivnoi kartsinomy molochnoi zhelezy nespetsificheskogo tipa pri limfogennom metastazirovanii.

The relationship between the content of supernatant cytokines and the expression of non-specific type of markers of epithelial-mesenchymal transition markers in the presence (group II) and the absence of lymphogenous metastasis (group I) were studied in biopsy specimens of mammary invasive breast carcinoma. The concentrations of TNF-α, IFN-γ, G-CSF, GM-CSF, VEGF, MCP-1, IL-2, IL-4, IL-6, IL-8, IL-10, IL-17, IL-18, IL-1ß and IL-1Ra, as well as the expression of immunohistochemical (IHC) markers of the epithelial-mesenchymal transition - cadherin-E (CDH1), ß-1 integrin (CD29) and type II collagen (CII) were assayed. Results have shown that patients of these groups statistically significantly differed in spontaneous production of IL-18 and G-CSF, in terms of the index of the effect of the polyclonal activator on G-CSF production. There was a correlation between the parameter of CII expression in tumor tissue and the production of cytokines by tumor biopsy specimens; it was characteristic of all patients with invasive carcinoma of a non-specific type, and correlations, both direct and reverse between the expression indices of CDH1, CD29 and cytokine production varied depending on the presence or the absence of lymphogenous metastasis. The study revealed the features of the correlation between the production of cytokines by the tumor, its microenvironment and the expression of IHC markers of the epithelial-mesenchymal transition in patients with invasive non-specific breast carcinoma in the presence and absence of lymphogenous metastasis.

Flow Cytometry Characterization of Pluripotent Transmembrane Glycoproteins on Resident Cervix Uteri Cells in Patients Screened for Cervical Cancer.

The aim of this study was to characterize both by flow cytometry analysis and immunohistochemistry cervix uteri cells of nulliparous women screened for cervical intraepithelial neoplasia (CIN) in comparison to a group without CIN by using mesenchymal stem cell-like and hematopoietic lineage markers. A significant expression for CD29, CD38, HLA-I, and HLA-II was correlated positively to the CIN degree and it was more relevant in patients positive for human papilloma virus (HPV). Thus, identification and detailed characterization of pluripotent resident in uteri cells could be a promising therapeutic target.

Trophoblast-derived CXCL12 promotes CD56bright CD82- CD29+ NK cell enrichment in the decidua.

PROBLEM: Decidual natural killer (dNK) cells play key roles in maternal-fetal immune regulation, trophoblast invasion, and vascular remodeling, and most dNK cell populations are CD56bright CD16- NK cells. However, the enrichment and redistribution of dNK cells in the local decidua have not been clarified yet. METHOD OF STUDY: A total of 45 women with normal pregnancies and 8 unexplained recurrent spontaneous abortion (RSA) patients were included. We isolated primary human dNK (n = 53) and peripheral blood NK (pNK) cells (n = 5) from specimen and analyzed CD56, CD82, and CD29 by flow cytometry (FCM). We assessed their adhesion ability by cell counts of NK cells adhered to decidual stromal cells (DSCs) in a co-culture system. RESULTS: We found that RSA patients had more CD56dim dNK cells with lower CD82 and higher CD29 than women with normal pregnancies. There were negative correlations of CD82 to CD29 on CD56dim and CD56+ dNK cells. In normal pregnancies, dNK cells had lower CD82 and higher CD29 expression with a stronger adhesion ability than pNK cells. Blocking CD82 on dNK cells increased the adhesive ability and CD29 expression, while blocking CD29 decreased the adhesive ability. Co-culturing dNK cells with trophoblast cells decreased CD82 expression and increased the adhesive ability of dNK cells and the percentage of CD56bright NK cells, while blocking trophoblast-derived CXCL12 increased CD82 expression, decreased CD29 expression, and impaired the adhesive ability of NK cells. CONCLUSION: Trophoblast cells enhance the adhesive ability of NK cells to DSCs via the CXCL12/CD82/CD29 signaling pathway and contribute to CD56bright NK cell enrichment in the uterus.

ACAP4 interacts with CrkII to promote the recycling of integrin ß1.

ACAP4, a GTPase-activating protein (GAP) for the ADP-ribosylation factor 6 (ARF6), plays import roles in cell migration, cell polarity, vesicle trafficking and tumorigenesis. Similarly, the ubiquitously expressed adaptor protein CrkII functions in a wide range of cellular activities, including cell proliferation, T cell adhesion and activation, tumorigenesis, and bacterial pathogenesis. Here, we demonstrate that ACAP4 physically interacts with CrkII. Biochemical experiments revealed that ACAP4550-660 and the SH3N domain of CrkII are responsible for the interaction. Functional characterization showed that the interaction is required for the recruitment of ACAP4 to the plasma membrane where ACAP4 functions to regulate the recycling of the signal transducer integrin ß1. Thus, we suggest that the CrkII-ACAP4 complex may be involved in regulation of cell adhesion.

Histopathological and proteomic analyses identify integrin-ß1 as a potential mediator of phlebosclerosis in uremic patients.

BACKGROUND: Patients with uremia have an excessive mortality from cardiovascular disease (CVD). Arterial remodeling is mainly responsible for uremia-induced CVD and has been well studied, yet venous remodeling is poorly understood. Here we investigate the histopathology and proteomic profiles of venous remodeling in uremic patients. METHODS: Forearm cephalic veins were isolated from nine uremic patients during surgeries for arteriovenous fistula, and from nine healthy controls when applying surgical debridement. Hematoxylin-eosin, Masson's trichrome, von Kossa, and immunohistochemistry (IHC) against proliferating cell nuclear antigen were stained for histopathology. Isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis was executed to explore the proteome of the veins. The core regulatory protein was validated by western blot, IHC, and immunofluorescence. RESULTS: Phlebosclerosis, characterized by intimal rarefaction and medial thickening with disordered proliferation of vascular smooth muscle cells (VSMCs), was the prominent pathological manifestation of peripheral veins in uremic patients, while inflammatory cell infiltration, atherosclerosis or calcification were not obviously detected. iTRAQ analysis showed that 350 proteins were significantly changed in phlebosclerosis of uremic patients compared with healthy controls, of which integrin-ß1 (ITGß1) exhibited the strongest regulatory ability by intermolecular interaction network analysis. The enhanced ITGß1 expression was mainly co-expressed with the disordered proliferation of VSMCs while a little with vascular endothelial cells in the forearm cephalic veins of uremic patients. CONCLUSIONS: Phlebosclerosis is the prominent pathological manifestation in peripheral veins of uremic patients. This pathological alteration mainly attributes to the disordered proliferation of VSMCs, which is potentially mediated by ITGß1.

Spermatogonial stem cells identified by molecular expression of PLZF, integrin ß1 and reactivity to Dolichos biflorus agglutinin in alpaca adult testes.

The identification system of spermatogonial stem cell (SSC) was established in alpaca using the molecular expression as well as the reactivity pattern to Dolichos biflorus agglutinin (DBA) by flow cytometry. Twenty-four testicles with their epididymis were recovered from adult alpacas at the slaughterhouse of Huancavelica-Perú. Samples were transported to the Laboratory of Reproductive Physiology at Universidad Nacional Mayor de San Marcos. Testes were selected for our study when the progressive motility of epididymal spermatozoa (ESPM) was above 30%. Isolation of SSC was performed with two enzymatic digestions. Finally, sperm viability was evaluated by means of the trypan blue vital stain in spermatogonial round cells. Samples with more than 80% viability were selected. Isolated cells cultured for 2 days were used for identifying the presence of SSCs by the expression of integrin ß1 (116 bp) and PLZF (206 bp) genes. Spermatogonia were classified according to the DBA reactivity. Spermatogonia with a strong positive to DBA (sDBA+ ) were classified as SSC (Mean ± SEM=4.44 ± 0.68%). Spermatogonia in early differentiation stages stained weakly positive with DBA (wDBA+ ) (Mean ± SEM=37.44 ± 3.07%) and differentiated round cells as DBA negative (Mean ± SEM=54.12 ± 3.18%). With the use of molecular and DBA markers, it is possible to identify easily the spermatogonial stem cells in alpaca.

Garlicin Post-Conditioning Suppresses Adhesion Molecules in a Porcine Model of Myocardial Ischemia-Reperfusion Injury.

OBJECTIVES: To evaluate whether garlicin post-conditioning can attenuate myocardial ischemiareperfusion injury in a catheter-based porcine model of acute myocardial infarction (AMI) by affecting adhesion molecules integrin ß1/CD29 and platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31). METHODS: Twenty-two swine were devided into 3 groups: 6 in a sham-operation group, and 8 each in the model and garlicin groups. AMI porcine model was established in the model and garlicin groups. The distal parts of the left anterior descending coronary artery in the animals of the model and garlicin groups were occluded by dilated balloon for 2 h, followed by reperfusion for 3 h. Garlicin (1.88 mg/kg) was injected over a period of 1 h, beginning just before reperfusion, in the garlicin group. Real-time polymerase chain reaction, immunohistochemistry and Western blot were carried out to detect mRNA and protein expressions of CD29 and CD31 3 h after reperfusion. RESULTS: Hematoxylin-eosin staining showed a better myocardial structure in the garlicin group after reperfusion. Compared to the model group, garlicin inhibited both the mRNA and protein expression of CD29 and CD31 in reperfusion area and no-reflflow area (P<0.05 respectively). CONCLUSIONS: Garlicin post-conditioning induced cardio-protection against myocardial ischemia-reperfusion injury in this catheter-based porcine model of AMI. The cardio-protective effect of garlicin is possibly owing to suppression of production of CD29 and CD31, by inhibition of the mRNA expression of CD29 and CD31.

Systemic Injection of Substance P Promotes Murine Calvarial Repair Through Mobilizing Endogenous Mesenchymal Stem Cells.

Craniofacial defect is a critical problem in dental clinic, which has a tremendous impact on patients' quality of life. Mesenchymal stem cell-based therapy has emerged as a promising approach for tissue defect repair. However, reduced survival after mesenchymal stem cells (MSCs) transplantation remains as a major problem in this area, which hampers the outcome of regeneration. Recently, the mechanism to mobilize endogenous MSCs for tissue regeneration has received increasing attentions, as it does not require exogenous cell transplantation. The primary goal of this study was to confirm the role of intravenous substance P in mobilizing endogenous CD45-CD11b-CD29+ MSCs in critical-sized bone defect animals and to investigate the effects of substance P on calvarial bone repair. Flow cytometry analyses revealed that intravenous substance P promoted the mobilization of endogenous CD45-CD11b-CD29+ MSCs after bone defect. In addition, Micro-CT showed that intravenous substance P improved the outcomes of calvarial bone repair. Furthermore, we discovered that systemic injection of substance P attenuated inflammation and enhanced the survival of the local-transplanted GFP+ MSCs. Our findings suggested that substance P together with its mobilized CD45-CD11b-CD29+ MSCs helped improve calvarial defect repair through regulating inflammatory conditions and promoting the survival of local-transplanted cells.

Altered Integrins Expression of Patients Affected by Cryptorchidism.

OBJECTIVES: The study aimed to investigate the expression of the integrin isoforms α7A and ß1A, expressed by myogenic precursor cells, and α7B and ß1D, expressed by mature muscle cells in the cremaster of patients affected by an undescended testis. METHODS: Fifteen samples of cremaster were obtained from patients undergoing surgery for an undescended testis. Thirty control specimens of cremaster were harvested from patients with congenital hydrocele or inguinal hernia. Immunofluorescent analysis was carried out using anti-α7A, ß1A, α7B, and ß1D integrin antibodies. Sections were observed using confocal laser scanning microscopy. RESULTS: As compared with controls, a significant loss of a α7B (p = 0.0355) and ß1D (p = 0.0069) integrins and a higher expression of α7A (p = 0.0003) and ß1A (p = 0.0150) was detected in the cremaster of patients affected by an undescended testis. CONCLUSIONS: Our data document a critical alteration of the cytoskeleton of cremasteric smooth muscle cells in patients with an undescended testis. This might explain the altered function in smooth muscle cells in cremaster implied during testicular descent. We therefore speculate that the postnatal splicing of α7A to α7B and of ß1A to ß1D integrins is delayed. This could account for the common clinical scenario of spontaneous descent of the testes in the first months of life.

miR-200c/141 Regulates Breast Cancer Stem Cell Heterogeneity via Targeting HIPK1/ß-Catenin Axis.

Increasing evidence demonstrates the existence of two inter-convertible states of breast cancer stem cells (BCSCs) with distinct behaviors in proliferation and mobility, and the BCSC heterogeneity is accurately regulated by sophisticated mechanisms including microRNAs. The microRNA-200 family including miR-200c/141 cluster was reported to affect cancer cell invasion and metastasis by regulating epithelial to mesenchymal transition (EMT). However, the effect of miR-200 family on BCSC heterogeneity is uncertain. Thus, we investigated whether the miR-200c/141 cluster had different effects on breast tumor growth and metastasis by switching the two states of BCSC. Methods: The spontaneous mammary tumor mouse model with miR-200c/141 conditional knockout was utilized for analyzing the role of miR-200c/141 cluster in vivo. The effect of miR-200c/141 cluster on BCSCs was performed by CD24/CD29 staining and ALDEFLUOR assay. miR-200c/141 target expression and EMT-related marker expression were verified in tumor sections, primary cells and breast cancer cell lines by qRT-PCR or western blotting. Statistical analysis was determined using two-way ANOVA and Student's t-test. All values were presented as the mean ± s.e.m. Results: The deletion of miR-200c/141 cluster regulated BCSC heterogeneity and promoted the EMT-like BCSC generation, which resulted in increased tumor metastasis and inhibited tumor growth by directly upregulating the target gene homeodomain-interacting protein kinase 1 (HIPK1) and sequential ß-catenin activation. Conclusions: Our results indicated that miR-200c/141 played biphasic roles in breast tumor progression via affecting the BCSC heterogeneity, suggesting targeting BCSC heterogeneity to simultaneously restrict breast cancer initiation and metastasis could be a promising therapeutic strategy for breast cancer.

Endoplasmic reticulum stress-induced cell death in podocytes.

Endoplasmic reticulum (ER) stress occurs in a variety of pathophysiological mechanisms, and there has been great interest in managing this pathway for the treatment of clinical diseases. Increased ER stress can block integrin-ß1 glycosylation, decrease integrin-ß1 protein expression and enhance cell death in podocytes. Autophagy is closely interconnected with ER stress to counteract the possible injurious effects related to the impairment of protein folding and is one of the intracellular protein degradation systems. Studies have shown that podocytes exhibit a high rate of autophagy to maintain as terminally differentiated cells. We have attempted to induce autophagy in podocytes with ER stress to increase the longevity of proteins and the degradation of damaged organelles. However, regardless of ER stress or autophagy that protects the cells at early stages, cells cannot adapt to this situation when the stress is already well established, and podocytes will undergo severe injury finally. In summary, ER stress may induce cell death in podocyte, and autophagy mediate to salvage the injuries caused by ER stress in the short term. It seems that adequate, but not excessive, autophagy is crucial to help maintain the cell viability of podocytes.

[Effect of mesenchymal stem cells on the apoptosis of breast cancer cells induced by cisplatin].

Objective: To investigate the effect of mesenchymal stem cells (MSCs) on apoptosis of breast cancer cell line MCF-7 induced by cisplatin (DDP), MSCs derived from breast cancer (BC-MSCs) or adjacent non-cancerous tissues (BN-MSCs) were isolated, cultured and identified. Methods: BC-MSCs and BN-MSCs were isolated and cultured by tissue adherent method. The differentiation potential of BC-MSCs was detected by osteogenic and adipogenic induction, and cell surface markers of BC-MSCs and BN-MSCs were evaluated by flow cytometry. MCF-7 cells were co-treated with DDP and conditioned medium (CM) collected from BC-MSCs and BN-MSCs after being cultured for 48 hours, respectively. Inhibition rate of cell proliferation was evaluated by MTT. Cell apoptosis and viability were detected by MUSE cell analyzer. Cytokines in MSC-CM were detected by Luminex liquid chip. Interleukin 6 (IL-6) mRNA expressions in MCF-7 cells with different treatment were detected by RT-PCR. Results: The morphology of BC-MSCs and BN-MSCs successfully isolated and cultured was uniform fibroblast-like clusters under the microscope. These cells expressed high levels of CD29 and CD44, but neither CD14 nor CD34 were detected. MSCs could also differentiate into osteoblasts and adipocytes after specific induction. After treatment with 2.5, 5, 10, 20, 40 and 80 µmol/L DDP, the inhibitory rates of proliferation of MCF-7 cells in DDP group were (17.33±2.00)%, (22.37±0.73)%, (30.77±1.23)%, (44.93±1.27)%, (62.03 ±1.97)% and (73.93±1.10)%, respectively. While the inhibitory rates of DDP+ BC-MSCs group were (8.27±0.63)%, (11.50±1.30)%, (20.57±0.93)%, (32.60 ±1.90)%, (52.27±0.73)% and (62.13±2.17)%, respectively. The inhibitory rates of DDP+ BN-MSCs group were (12.90±1.60)%, (16.53±2.87)%, (25.90±1.50)%, (39.40±2.40)%, (57.40±0.70)% and (69.03±1.07)%, respectively. The inhibitory rates of DDP+ BC-MSCs group were significantly lower than those of DDP group (P<0.05). The apoptotic rates of MCF-7 cells in DDP group, DDP+ BC-MSCs group and DDP+ BN-MSCs group were (47.77±1.98)%, (29.20±2.12)% and (37.92±2.21)%, respectively. The apoptotic rates of DDP group was significantly higher than that of DDP+ BC-MSCs group (P<0.05). The cell viabilities of MCF-7 in DDP group, DDP+ BC-MSCs group and DDP+ BN-MSCs group were 0.52±0.02, 0.72±0.02 and 0.64±0.02, respectively. The cell viability of DDP group was significantly lower than that of DDP+ BC-MSCs group (P<0.05). The result of Luminex liquid chip analysis showed that, the level of IL-6 in BC-MSCs group increased 2.50±0.68 fold when compared with BN-MSCs group (P<0.05). The relative expressions of IL-6 mRNA in DDP group and DDP+ BC-MSCs group were 1.02±0.10 and 7.58±0.55, respectively, with a statistically significant difference (P<0.01). The apoptotic rates of MCF-7 cells in DDP+ BC-MSCs group with or without IL-6 neutralizing antibody were (27.41±1.95)% and (42.45±2.87)%, respectively, with a statistically significant difference (P<0.05). The cell viabilities of MCF-7 cells in DDP+ BC-MSCs group with or without IL-6 neutralizing antibody were (72.40±2.60)% and (59.76±3.89)%, respectively, with a statistically significant difference (P<0.05). Conclusions: BC-MSCs and BN-MSCs have been isolated and cultured successfully. Compared with BN-MSCs, BC-MSCs could attenuate the effect of DDP on MCF-7 cells, evidently decrease the apoptosis and increase the proliferation and vitality in an IL-6 dependent manner.

Evaluation of ß1-integrin expression on chondrogenically differentiating human adipose-derived stem cells using atomic force microscopy.

The expression of ß1-integrin on human adipose-derived stem cells, differentiating toward a chondrogenic lineage, is hypothesized to decrease when cells are grown under in vivo-like environments due to sufficient extracellular matrix (ECM) buildup in the engineered tissues. The opposite is true when cells are grown in static cultures such as in pellet or micromass. To probe ß1-integrin distribution on cellular surfaces, atomic force microscopy cantilevers modified with anti-ß1-integrin antibodies were used. Specific antibody-antigen adhesion forces were identified and indicated the locations of ß1-integrins on cells. ECM properties were assessed by estimating the Young's modulus of the matrix. Specific single antibody-antigen interactions averaged 78 ± 10 pN with multiple bindings occurring at approximate multiples of 78 pN. The author's results show that upregulated ß1-integrin expression coincided with a less robust ECM as assessed by mechanical properties of tissues. In micromass and pellet cultures, transforming growth factor ß3(TGF-ß3) elicited a decrease in Young's modulus by 3.7- and 4.4-fold while eliciting an increase in ß1-integrin count by 1.1- and 1.3-fold, respectively. ß1-integrin counts on cells grown in the presence of TGF-ß3 with oscillating hydrostatic pressure decreased by a 1.1-fold while the Young's modulus increased by a 1.9-fold. Collectively, our results suggest that cells in insufficiently robust ECM express more integrin perhaps to facilitate cell-ECM adhesion and compensate for a looser less robust ECM.

Integrin Ligation Results in Nephrin Tyrosine Phosphorylation In Vitro.

Nephrin is expressed at the basolateral aspect of podocytes and is an important signaling protein at the glomerular slit diaphragm. In vitro studies have demonstrated that Nephrin phosphorylation-dependent signaling is able to assemble a protein complex that is able to polymerize actin. However, proximal signaling events that result in nephrin tyrosine phosphorylation are not well understood. Nephrin deletion in mice and human nephrin mutations result in developmental failure of the podocyte intercellular junction resutling in proteinuria. This has been presumed to be due to a failure to respond to an external polarized cue in the absence of nephrin or a failure to transduce an outside-in signal in patients with nephrin mutations. The nephrin extracellular domain binds to itself or neph1 across the foot process intercellular junction. Nephrin is tyrosine phosphorylation-silent in healthy glomeruli when presumably the nephrin extracellular domain is in an engaged state. These observations raise the possibility of an alternate proximal signaling mechanism that might be responsible for nephrin tyrosine phosphorylation. Here we present data showing that integrin engagement at the basal aspect of cultured podocytes results in nephrin tyrosine phosphorylation. This is abrogated by incubating podocytes with an antibody that prevents integrin ß1 ligation and activation in response to binding to extracellular matrix. Furthermore, nephrin tyrosine phosphorylation was observed in podocytes expressing a membrane-targeted nephrin construct that lacks the extracellular domain. We propose, integrin-activation based signaling might be responsible for nephrin phosphorylation rather than engagment of the nephrin extracellular domain by a ligand.

Unusual variants of intravascular malignant hematopoietic neoplasms: a report of 4 cases and review of the literature.

Intravascular lymphoma (IVL) is a rare and fatal disease, typically of B-cell origin. Most of the reported cases have been for primary IVL, and only a minority of cases are of recurrent IVL. In addition, recurrent IVL occurring after treatment of anaplastic large T-cell lymphoma (ALCL) by contrast is extraordinarily rare. In this article, we present 3 cases of recurrent cutaneous IVL (2 men and 1 woman) and compare these with 1 case of primary IVL. The patients ranged in age from 56 to 73 years and were encountered in the routine dermatopathology and consultative practices of one of the authors. In 2 of the cases, the patients had intravascular cutaneous ALCL. In regard to the remaining 2 patients, 1 patient had a recurrent intravascular cutaneous follicular lymphoma in the context of a history of diffuse large B-cell lymphoma. The fourth patient had a primary intravascular ALCL because there was no antecedent history. In all cases, the skin biopsies showed large aggregates of atypical cells within the blood vessels. Phenotypic studies revealed variable staining results with CD29 and CD54 in cases of recurrent IVL compared with those of primary IVL. Recurrent cutaneous IVL represents a somewhat heterogeneous group of lymphoproliferative disorders with a distinct variant being in the context of intravascular ALCL; the mechanisms of intravascular localization in recurrent IVL are likely different from those of primary IVL.

Differential expression of stem cell-like proteins in normal, hyperplastic and dysplastic oral epithelium.

OBJECTIVE: The identification of stem cells (SC) remains challenging. In the human oral mucosal epithelium, these cells are believed to be in the basal layer (stem cell niche), but their exact location is unclear. The aim of this study was to examine the dysplastic oral epithelium for these SC-like proteins in order to assess their diagnostic value as biomarkers complementing the histological grading of dysplasia. MATERIAL AND METHODS: Thirty oral epithelial dysplasia (OED), 25 oral lichen planus (OLP), 10 oral hyperkeratosis and 5 normal oral epithelium (OE) were immunohistochemically examined for four SC markers [integrin ß1, neuron-glial-2 (NG2), notch 1 (N1) and keratin 15 (K15)]. RESULTS: Three of four SC markers were heterogeneously detected in all samples. K15 overexpression in the lower two-thirds of severe OED suggests an expanded SC niche. Integrin ß1 distribution pattern was not measurably different between OEDs and control. NG2 was almost negative to absent in all samples examined. N1 expression was weak and highly variable in normal and dysplastic epithelium, making it an unreliable epithelial stem cell marker. CONCLUSIONS: Present findings suggest that these markers were unable to identify individual epithelial stem cells. Instead, subpopulations of cells, most probably stem cells and transit amplifying cells with stem cell-like properties were identified in the dysplastic oral epithelium. The characteristic expressions of K15 might be of diagnostic value for oral dysplasia and should be investigated further.

Activation of signal transducer and activator of transcription 5 (STAT5) is linked to ß1-integrin protein abundance in unilaterally milked bovine mammary glands.

Prolactin (PRL) is important in the regulation of milk synthesis in mammary epithelial cells (MEC). In cattle, circulating levels of PRL are not limiting, suggesting the possible involvement of other factors that may control the response to PRL at the cellular level. The effects of milking frequency (MF) on milk synthesis are controlled locally within mammary glands and involve PRL signaling. To further investigate this relationship between MF and PRL signaling, udder halves of 17 dairy cows were milked either 4 times a day (4×) or once a day (1×) for 14 d in early lactation. Mammary biopsies were obtained 3 to 5h following milking from both udder halves of 10 cows, and changes in PRL and associated pathways were measured. The abundance of STAT5A mRNA was higher after 4× milking, whereas that of the PRL receptor (PRLR) and STAT3 were lower relative to that after 1× milking. In 4× mammary tissues, the protein levels of STAT5, activated STAT5, and ß1-integrin were higher, whereas the those of the long isoform of PRL receptor and activated STAT3 were lower than 1× tissues. The activation of STAT5 correlated strongly with major milk protein mRNA abundance (r=0.86 to 0.94) and ß1-integrin protein levels (r=0.91). These results confirm that major milk protein gene expression is associated with STAT5 activation and suggests that the STAT5 and ß1-integrin signaling pathways are linked. Modulation of ß1-integrin abundance in response to changes in MF may be a mechanism that controls the MEC ability to respond to PRL and therefore its secretory activity.