Interactions between the Astrocytic Volume-Regulated Anion Channel and Aquaporin 4 in Hyposmotic Regulation of Vasopressin Neuronal Activity in the Supraoptic Nucleus

We assessed interactions between the astrocytic volume-regulated anion channel (VRAC) and aquaporin 4 (AQP4) in the supraoptic nucleus (SON). Acute SON slices and cultures of hypothalamic astrocytes prepared from rats received hyposmotic challenge (HOC) with/without VRAC or AQP4 blockers. In acute slices, HOC caused an early decrease with a late rebound in the neuronal firing rate of vasopressin neurons, which required activity of astrocytic AQP4 and VRAC. HOC also caused a persistent decrease in the excitatory postsynaptic current frequency, supported by VRAC and AQP4 activity in early HOC; late HOC required only VRAC activity. These events were associated with the dynamics of glial fibrillary acidic protein (GFAP) filaments, the late retraction of which was mediated by VRAC activity; this activity also mediated an HOC-evoked early increase in AQP4 expression and late subside in GFAP-AQP4 colocalization. AQP4 activity supported an early HOC-evoked increase in VRAC levels and its colocalization with GFAP. In cultured astrocytes, late HOC augmented VRAC currents, the activation of which depended on AQP4 pre-HOC/HOC activity. HOC caused an early increase in VRAC expression followed by a late rebound, requiring AQP4 and VRAC, or only AQP4 activity, respectively. Astrocytic swelling in early HOC depended on AQP4 activity, and so did the early extension of GFAP filaments. VRAC and AQP4 activity supported late regulatory volume decrease, the retraction of GFAP filaments, and subside in GFAP-VRAC colocalization. Taken together, astrocytic morphological plasticity relies on the coordinated activities of VRAC and AQP4, which are mutually regulated in the astrocytic mediation of HOC-evoked modulation of vasopressin neuronal activity.

Oxytocin Modulation of Maternal Behavior and Its Association With Immunological Activity in Rats With Cesarean Delivery

Oxytocin (OT), a neuropeptide produced in the supraoptic (SON) and paraventricular (PVN) nuclei, is not only essential for lactation and maternal behavior but also for normal immunological activity. However, mechanisms underlying OT regulation of maternal behavior and its association with immunity around parturition, particularly under mental and physical stress, remain unclear. Here, we observed effects of OT on maternal behavior in association with immunological activity in rats after cesarean delivery (CD), a model of reproductive stress. CD significantly reduced maternal interests to the pups throughout postpartum day 1-8. On postpartum day 5, CD decreased plasma OT levels and thymic index but increased vasopressin, interleukin (IL)-1β, IL-6 and IL-10 levels. CD had no significant effect on plasma adrenocorticotropic hormone and corticosterone levels. In the hypothalamus, CD decreased corticotropin-releasing hormone contents in the PVN but increased OT contents in the PVN and SON and OT release from hypothalamic implants. CD also increased c-Fos expression, particularly in the cytoplasm of OT neurons. Lastly, CD depolarized resting membrane potential and increased spike width while increasing the variability of the firing rate of OT neurons in brain slices. Thus, CD can increase hypothalamic OT contents and release but reduce pituitary release of OT into the blood, which is associated with depressive-like maternal behavior, increased inflammatory cytokine release and decreased relative weight of the thymus.

Use and Cost-Effectiveness of a Telehealth Service at a Centralized COVID-19 Quarantine Center in Taiwan: Cohort Study

Background

Telehealth is a recommended method for monitoring the progression of nonsevere infections in patients with COVID-19. However, telehealth has not been widely implemented to monitor SARS-CoV-2 infection in quarantined individuals. Moreover, studies on the cost-effectiveness of quarantine measures during the COVID-19 pandemic are scarce.

Objective

In this cohort study, we aimed to use telehealth to monitor COVID-19 infections in 217 quarantined Taiwanese travelers and to analyze the cost-effectiveness of the quarantine program.

Methods

Travelers were quarantined for 14 days at the Taiwan Yangmingshan quarantine center and monitored until they were discharged. The travelers’ clinical symptoms were evaluated twice daily. A multidisciplinary medical team used the telehealth system to provide timely assistance for ill travelers. The cost of the mandatory quarantine was calculated according to data from the Ministry of Health and Welfare of Taiwan.

Results

All 217 quarantined travelers tested negative for SARS-CoV-2 upon admission to the quarantine center. During the quarantine, 28/217 travelers (12.9%) became ill and were evaluated via telehealth. Three travelers with fever were hospitalized after telehealth assessment, and subsequent tests for COVID-19 were negative for all three patients. The total cost incurred during the quarantine was US $193,938, which equated to US $894 per individual.

Conclusions

Telehealth is an effective instrument for monitoring COVID-19 infection in quarantined travelers and could help provide timely disease management for people who are ill. It is imperative to screen and quarantine international travelers for SARS-CoV-2 infection to reduce the nationwide spread of COVID-19.

Functional and Phenotypic Alteration of Intrasplenic Lymphocytes Affected by Mesenchymal Stem Cells in a Murine Allosplenocyte Transfusion Model

Previous data have demonstrated that mesenchymal stem cells (MSCs) can exert immunomodulatory activity in vitro, in which of the process nearly all kinds of immune cell subsets are involved. However, there is still a paucity of information about whether and why MSCs inhibit the ongoing immune responses in vivo. Working in a murine splenocyte transfusion model across the major histocompatibility barrier (C57BL/6 → BALB/c, H2b → H2d), we have found that MSC coinfusion prolongs the mean survival time (MST) of the recipient mice in a dose-dependent manner and reduces graft-versus-host-associated histopathology in comparison to the allosplenocyte transfusion controls. In vivo eGFP tracing with polymerase chain reaction analysis revealed that grafted MSCs could migrate and settle into the lungs, spleen, liver, intestine, and skin shortly after administration. Further investigations into the functional characteristics of intrasplenic lymphocytes showed that their proliferation and cytotoxic activity against P815 cells (H2d) were significantly restrained by MSC cotransfer. FACS analysis demonstrated that MSC infusion not only increased the proportion of CD4+ subset but also decreased that of CD8+ cells at the belated observation points, resulting in the increase of the ratio of CD4+/CD8+ cells. Also, in contrast to the slight increase of the proportion of CD4+CD25+ T regulatory cells (Tregs) in MSC cotransfer mice, the ratio of Tregs/CD8+ cells was dramatically elevated. Furthermore, RT-PCR analysis on the cytokine array of IL-2, IL-4, IL-12, TNF-α, and TGF-β in recipient splenocytes implied the Th1 to Th2 polarization. Therefore, it is deducible that alteration in the proportions of different T-lymphocyte subsets may be one of the main mechanisms by which grafted MSCs suppress the ongoing immune responses in vivo. The study here might provide some new clues for the design of therapeutic approaches for MSC transplantation.

[Research advances of anti-CD40 monoclonal antibody]

CD40 and its receptor CD40L are a very important pair of co-stimulating molecule in immune response, which have extensive biological effects. After stimulating CD40 signal, it can exert corresponding function through MAPK (JNK, ERK, p38) pathway, PI3K cascade, as well as NF-κB and STAT. The CD40 signal is closely related to tumor immunity, this moleculer has already become targeted-molecule for cancer treatment. Recently, there have been many anti-CD40 monoclonal antibodies displaying good anti-cancer effect, among which CHIR-12.12, SGN-40 and CP-870, 893 developed rapidly and successively have entered clinical research stage. This review focuses the status of anti-CD40 monoclonal antibody, including distribution of CD40, physiological function of CD40, CD40 and tumor immunity, anti-CD40 monoclonal antibodies and so on.

[Hyperactivation of c-Jun NH(2)-terminal protein kinase contributes to the proliferation of B lymphoma cells]

This study was purposed to explore the effect of hyperactivation of c-Jun NH(2)-terminal protein kinase (JNK) on the proliferation of B lymphoma cells. The human B lymphoma cell lines Daudi and Raji were chosen as research objects. The expression of JNK protein was determined by Western blot. The subcellular localization of JNK protein was detected by immunofluorescence. The cell cycle was analyzed by flow cytometry. The suppressive effect of JNK inhibitor SP600125 on the proliferation of Daudi and Raji cells was assayed by ATPLite method. The results demonstrated that hyperactivation of JNK has been found in Daudi and Raji cells. Immunofluorescence confirmed the aberrant subcellular localization of JNK protein in Daudi and Raji cells. Cell cycle assay revealed that Daudi and Raji cells underwent G(2)-M arrest in the presence of SP600125. Furthermore, Daudi and Raji cells showed significant increase in sub-G(1) population, an indicator of apoptotic cells, with the treatment of JNK inhibitors. These data suggested that JNK inhibitors suppressed the growth of B lymphoma cells via cell cycle arrest and apoptosis. Daudi and Raji cells treated with different concentrations of JNK selective inhibitor SP600125 showed dose-dependent reduction in the growth of Daudi and Raji cells. It is concluded that hyperactivation of JNK enhance the proliferation of Daudi and Raji cells. The aberrant subcellular localization of JNK protein may facilitate the nuclear accumulation of basal JNK activity, which made JNK to be a potential target to treat human B lymphoma.

[Influence of excessive complement activation on pathological process of acute graft versus host disease in mice]

This study was aimed to explore the influence of excessive complement activation on the pathological process of acute graft-versus-host disease (aGVHD) in mice. A murine model with aGVHD was established by injecting cell mixture containing splenocytes and bone marrow cells at 2:1 ratio from donor C57BL/6(H-2K(b)) mice into recipient BALB/c (H-2K(d)) mice within 4-6 hours after 8 Gy (60)Co γ-ray total body irradiation. The mice received syngeneic bone marrow transplantation were used as control group. After transplantation, the mice were monitored daily for body weight and mortality. At day 14, all mice were sacrificed and each liver was freshly dissociated for histological analysis. The hepatic mRNA abundance for complement components C3a and C5a as well as receptors for these two anaphylatoxin were tested by real-time quantitative PCR method. And the levels of C3a and C5a production in liver were detected by ELISA. The deposition of complement C3 in liver was determined by immunofluorescence staining using frozen section. The results indicated that as compared with syngeneic bone-marrow transplantation control group, experimental animals underwent aGVHD characterized by weight loss, depilation, diarrhea and lassitude. Interestingly, the hepatic mRNA expression for complement anaphylatoxin family member C3a and C5a as well as their receptors C3aR and C5aR1 in mice with aGVHD were significantly up-regulated in comparison with control group (p < 0.05). Consistently, the content of C3a and C5a in liver increased markedly in mice with aGVHD (p < 0.01). For animals ongoing aGVHD, complement component C3 depositions were observed in hepatic portal areas, around which massive inflammatory cell infiltration was also observed. It is concluded that in aGVHD animals, excessive complement activation occurs, and the activated complement components participate in pathological process of the aGVHD.

CD3 mAb treatment ameliorated the severity of the cGVHD-induced lupus nephritis in mice by up-regulation of Foxp3+ regulatory T cells in the target tissue: kidney

Teff/Treg imbalance orchestrated the onset and the progression of the lupus nephritis in a DBA/2→B6D2F1 murine model with cGVHD. In this paper, we first used 145-2C11 Ab to treat these human SLE-like diseased animals. The results showed that short-term low-dose anti-CD3 antibody treatment induced a significant remission of established proteinuria, production of autoantibodies, immune complex deposition and renal parenchyma lesions in lupus nephritic mice. Of note, we found a robust up-regulation of Foxp3 mRNA expression in the target tissue: kidney from mice with anti-CD3 antibody treatment compared to those with control IgG treatment. Likewise, an increased renal mRNA abundance for IL-10 was also observed in anti-CD3 antibody treated mice. In contrast, genes associated with inflammation and fibrosis as well as cytokines related to effector T cell responses were down-regulated by anti-CD3 mAb treatment. These findings suggested that short-term low-dose anti-CD3 antibody treatment might induced an IL-10-secreting Foxp3(+) regulatory T cells in this cGVHD target tissue: kidney, that suppressed the activation of effector T cells (Th1, Th2 and Th17), thus ameliorating the severity of the lupus nephritis in mice.

[Establishment and evaluation of experimental sepsis mouse model]

After treating with chemotherapy or immunosuppressant, malignant diseases of hematopoietic system such as leukemia, malignant lymphoma and aplastic anemia usually induced severe infection such as sepsis. Sepsis which is hard to be diagnosed causes high death rate. This study was purposed to establish an experimental sepsis mouse model so as to provide a basis for pathogenesis and intervention study. A classic caecal ligation and puncture (CLP) was used to establish experimental sepsis model. ELISA was used to detect levels of C5a, IL-6, TNFalpha, and IFN-gamma. Flow Cytometry was applied to measure apoptosis of lymphocytes in thymus and mesentery. The pathologic changes of thymus and spleen were confirmed by HE staining. The results showed that almost 70%-80% mice died at 72 hours after CLP. Only approximate 20% animal survived during finite time, mice in CLP group had significant weight lose. Meanwhile large release of different inflammatory mediators which are related with sepsis (C5a, IL-6, TNF-alpha, and IFN-gamma) was observed after CLP. Apoptosis of lymphocytes in thymus and mesentery lymphonodus was enhanced markedly after CLP. Significantly pathologic injury was also observed in thymus and spleen. It is concluded that a mouse model of experimental sepsis was successfully established by caecal ligation and puncture which can well mimic the clinical symptom of sepsis. The experimental sepsis mouse model provides an excellent tool for exploring the pathogenesis and intervention ways for sepsis accompanied with complicated malignant hematological diseases in vivo.

[Separation of immortalized mesenchymal stem cell like stromal cells of mouse embryonic aorta-gonad-mesonephros region and their biological characteristics]

To investigate the effects of microenvironment of aorta-gonad-mesonephros (AGM) on embryonic hematopoiesis, mesenchymal stem cell like stromal cells (MSC like stromal cells) derived from dorsal aorta (DA) in AGM region were separated and identified by their growth characteristics, related molecules expression and mesenchymal lineage potentials. Stromal cells from DA region in mouse embryos (E11.5) were isolated and cultured in vitro. After transfected by pSV3neo-SV40, the clones with G418 resistance were selected, and their growth characteristics were studied. The related molecules were analyzed by flow cytometry, and each clone was induced to differentiate into adipocytes, osteocytes, and chondrocytes. The results showed that most clones (20 clones) selected in the mouse DA region held the morphology of fibroblastoid cells. mDAF3 and mDAF18 could be grown in culture for more than 50 passages with G418 resistance, both have the potential to differentiate into adipocytes, osteocytes, and chondrocytes. At the logarithmic growth period, the cell population doubling time is about 24 hours. Surface markers, such as CD29, CD44, CD105 and Sca-1 were positively detected, while low levels of CD34, CD45, and CD31 were detected. It is concluded that immortalized mDAF3 and mDAF18 have the specific phenotype and differential potency of MSC, which suggests that MSC maybe exist in mouse embryonic DA region, where the MSC like stromal cells can be used as a cell model for further research on the modulation activity of DA microenvironment for embryonic hematopoiesis.

Apoptosis induced by depsipeptide FK228 coincides with inhibition of survival signaling in lung cancer cells

BACKGROUND

Whereas histone deacetylase inhibitors are known to modulate chromatin structure, the precise mechanisms by which these novel agents induce apoptosis in cancer cells remain unknown. Previously we reported that depsipeptide FK228 depletes epidermal growth factor receptor (EGFR), erbB2, and Raf-1 kinases in non-small cell lung cancer cells. In the present study we sought to further define the mechanisms by which FK228 modulates oncoprotein signaling and to ascertain whether altered signal transduction contributes to FK228-mediated apoptosis in lung cancer cells.

METHODS

Cultured non-small cell lung cancer cells were treated with FK228 alone or FK228 with a variety of kinase inhibitors. Proliferation and apoptosis mediated by drug exposure were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium, and Apo-BrdU techniques. Western blot and kinase assays were used to evaluate EGFR-related signal transduction pathways. Lung cancer cells were transduced with adenoviral vectors expressing activated AKT or mitogen-activated protein kinase kinase (MEK) 1 or beta-galactosidase to determine whether constitutive activation of mitogen-activated protein kinase signaling could abrogate FK228-mediated apoptosis.

RESULTS

FK228 treatment induced time-dependent apoptosis in lung cancer cells expressing wild-type or mutant EGFR. FK228 inhibited a variety of EGFR-related pathways including Src, RAF-MEK-extracellular signal-regulated kinase (ERK) 1/2 and phosphatidyl inositol-3 kinase (PI3K)/AKT, resulting in down-regulation of Bcl-2 and Bcl-xL and up-regulation of Bax. The kinase inhibitors AG1478, AG825, PD98059, and LY294002 markedly enhanced FK228-induced apoptosis in lung cancer cells. Coincident with inhibition of ERK1/2 and PI3K/AKT survival pathways, FK228 enhanced p38 and stress-activated protein kinase/c-Jun NH2-terminal kinase stress signaling. Constitutive expression of MEK1 but not AKT markedly reduced FK228-mediated apoptosis in lung cancer cells.

CONCLUSIONS

FK228 inhibits EGFR expression and modulates a variety of downstream mediators regulating proliferation and stress responses in lung cancer cells. These data highlight the significance of MEK signaling with respect to FK228-mediated apoptosis and support evaluation of histone deacetylase inhibitors in conjunction with agents specifically targeting mitogen-activated protein kinases in patients with lung cancer.

FK228 inhibits Hsp90 chaperone function in K562 cells via hyperacetylation of Hsp70

Some pan-histone-deacetylase (HDAC) inhibitors have recently been reported to exert their anti-leukemia effect by inhibiting the activity of class IIB HDAC6, which is the deacetylase of Hsp90 and alpha-tubulin, thereby leading to hyperacetylation of Hsp90, disruption of its chaperone function and apoptosis. In this study, we compared the effect of a class I HDAC inhibitor FK228 with the pan-HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) on the Hsp90 chaperone function of K562 cells. We demonstrated that, although having a weaker inhibitory effect on HDAC6, FK228 mediated a similar disruption of Hsp90 chaperone function compared to SAHA. Unlike SAHA, FK228 did not mediate hyperacetylation of Hsp90, instead the acetylation of Hsp70 was increased and Bcr-Abl was increasingly associated with Hsp70 rather than Hsp90, forming an unstable complex that promotes Bcr-Abl degradation. These results indicated that FK228 may disrupt the function of Hsp90 indirectly through acetylation of Hsp70 and inhibition of its function.

[Histone deacetylase inhibitor SAHA induces inactivation of MAPK signaling and apoptosis in HL-60 cells]

The study was aimed to investigate the molecular mechanisms of histone deacetylase inhibitor SAHA-induced apoptosis of acute myeloid leukemia cell line HL-60. The effect of SAHA on HL-60 cell proliferation was detected by MTT assay and the cell morphological changes were observed with Wright-Giemsa and Hoechst33342 staining. The cell cycle distribution was determined by flow cytometry and the expression of cell signaling proteins were detected by Western-blot analysis. The results showed that SAHA inhibited the proliferation of HL-60 cells in dose- and time-dependent manners, after 2 micromol/L SAHA exposure for 12 - 48 hours, the cell cycle was arrested at G(0)/G(1) phase and apoptotic cell death was confirmed by either defined apoptotic bodies stained by Hoechst33342, Western blot showed cleaved-PARP, which represents the activation of caspase 3. The Western blot analysis indicated the activation of two important survival signal pathways after SAHA treatment, the phosphorylation of Raf and its downstream ERK kinases were remarkable downregulated, whereas the phosphorylation of AKT and its downstream molecular mTOR were not changed. It is concluded that SAHA-induced apoptosis of HL-60 cells is mediated by inactivation of p44/42 MAPK signaling pathway.

Functional and phenotypic alteration of intrasplenic lymphocytes affected by mesenchymal stem cells in a murine allosplenocyte transfusion model

Previous data have demonstrated that mesenchymal stem cells (MSCs) can exert immunomodulatory activity in vitro, in which of the process nearly all kinds of immune cell subsets are involved. However, there is still a paucity of information about whether and why MSCs inhibit the ongoing immune responses in vivo. Working in a murine splenocyte transfusion model across the major histocompatibility barrier (C57BL/6 -BALB/c, H2b --> H2d), we have found that MSC coinfusion prolongs the mean survival time (MST) of the recipient mice in a dose-dependent manner and reduces graft-versus-host-associated histopathology in comparison to the allosplenocyte transfusion controls. In vivo eGFP tracing with polymerase chain reaction analysis revealed that grafted MSCs could migrate and settle into the lungs, spleen, liver, intestine, and skin shortly after administration. Further investigations into the functional characteristics of intrasplenic lymphocytes showed that their proliferation and cytotoxic activity against P815 cells (H2d) were significantly restrained by MSC cotransfer. FACS analysis demonstrated that MSC infusion not only increased the proportion of CD4+ subset but also decreased that of CD8+ cells at the belated observation points, resulting in the increase of the ratio of CD4+/CD8+ cells. Also, in contrast to the slight increase of the proportion of CD4+CD25+ T regulatory cells (Tregs) in MSC cotransfer mice, the ratio of Tregs/CD8+ cells was dramatically elevated. Furthermore, RT-PCR analysis on the cytokine array of IL-2, IL-4, IL-12, TNF-alpha, and TGF-beta in recipient splenocytes implied the Thl to Th2 polarization. Therefore, it is deducible that alteration in the proportions of different T-lymphocyte subsets may be one of the main mechanisms by which grafted MSCs suppress the ongoing immune responses in vivo. The study here might provide some new clues for the design of therapeutic approaches for MSC transplantation.

[Cloning, expression and purification of human stem cell growth factor cDNA and its species-specificity in hematopoiesis]

Stem cell growth factor (SCGF) is an early-acting hematopoitic cytokine that has two isoforms including hSCGF with full length molecules and hSCGFbeta, 78 amino acids of which lost in the conserved calcium-dependent carbohydrate-recognition domain (CRD). It has been demonstrated that hSCGFbeta is strictly species-specific in regulating he-matopoiesis. This study was aimed to explore whether human SCGF can exert synergistic stimulatory effect on heterogenous murine CFU-GM progenitor. Firstly, hSCGF cDNA was amplified from human fetal liver cDNA library by using two-step PCR. The hSCGF mature peptide coding sequence was subsequently placed at downstream of glutathione S-transferase (GST) sequence in GST gene fusion expression vector. The results indicated that there existed an additional 60 kD protein compared with mock BL21 when the cells hosting recombinant plasmid were induced with IPTG at 37 degrees C. SDS-PAGE analysis demonstrated that the GST-hSCGF fusion protein mainly existed in insoluble form. When induced at low temperature (28 degrees C), the recombinant protein was mostly soluble. The GST-fusion recombinant protein was subsequently purified by using affinity chromatography. The clonogenic assay revealed that, unlike hSCGFbeta, hSCGF had the granulocyte/macrophage promoting activity (GPA) for murine bone marrow GM progenitor. It is concluded that, in contrast to human SCGFbeta, the intact molecular hSCGF may have no species specificity, implying that CRD domain in human SCGFbeta does not directly bind to corresponding SCGF receptor, but may have certain biological function.

[Establishment of nonmyeloablative allogeneic stem cell transplantation model in H-2 haploidentical mice and its related study]

To explore the feasibility of nonmyeloablative conditioning regimens, hematopoietic reconstitution, chimera level and the occurrence of GVHD after nonmyeloablative allogeneic stem cell transplantation in H-2 haploidentical mice, CB6F1 mice were used as the recipient and were divided into 3 groups, mice were pretreated five days before transplantation. Group A was pretreated with myeloablative conditioning regimens (TBI with 10.5 Gy), group B was pretreated by TBI (2 Gy) + Ara-C + Cy and group C-TBI (2 Gy) + Ara-C + CY + Flu, respectively. For all recipient mice, the prevention of GVHD was not given, and 2 x 10(7) bone marrow cells mixed 1 x 10(7) spleen cells from C57BL/6 mice were injected through tail vein on day 0, and then hematopoietic recovery, engraftment and GVHD of recipients were observed. The results of chimera detection after transplantation showed that the engraftment of group A remained full donor chimerism, and engraftments of group B and group C were associated with mixed chimerism or full donor chimerism, but the chimerism of group B remained below 80% and tended to decrease after 50 days whereas chimerism of group C was above 80% (chimerism close to or being full donor type) and preserved even after 50 days. GVHD occurred in all the recipient mice due to that prevention was not given, wherein the occurrence and death rate of GVHD in group A was obviously higher than that of group B and group C (P <0.01), but there was no statistical difference between group B and group C. In conclusion, the nonmyeloablative conditioning regimens mainly based on fludarabine can form stable and lasting engraftment in the body of recipients. The mixed chimerism established in recipients induce tolerance of transplantation and decrease or avoid the occurrence of GVHD.

[Modification of in situ cryopreservation of human bone marrow mesenchymal stem cells]

The study was aimed to evaluate if the modified in situ cryopreservation could affect the biological function of mesenchymal stem cells (MSC) in vitro. Mesenchymal stem cells from human bone marrow were isolated by standard method and characterized with their morphology, cell-surface antigen profile and differentiation repertoire in vitro. The culture-expanded MSC were cryopreserved in situ with culture medium (DMEM-LG) containing 10% D MSO and 30% selected FCS in -70 degrees C. Following recovery of cryopreservation, differentiation to adipocytes, chondrocytes, and osteoblast in vitro and cell cycle analysis were performed to investigate whether the cryopreservation would change the differentiation potential of MSC. The results showed that after recovery of cryopreservation, there was no changes detected as compared with the culture-expanded MSC in both differentiation potency and growth pattern at 12 weeks. In conclusions: this optimized short term in situ cryopreservation at -70 degrees C could retain biological characteristics of human MSC for at least 3 months, and this method may be useful for cryopreservation of hum an bone marrow MSCs.

[Development of methodology for isolation and culture of mesenchymal stem cells derived from mouse skeletal muscle]

To address the question whether there exists mesenchymal stem cells in adult mouse skeletal muscle, mononuclear cells from muscle were obtained by digestion and density gradient centrifugation and plated in alpha-MEM/F12 medium containing 10% fetal bovine serum. Cell biological properties including morphology, cytochemistry, growth pattern and phenotypes as well were evaluated. Likewise, the osteogenesis of cultured cells was also observed. The results showed that adherent cells homogenous in shape proliferated quickly in the culture system. The phenotypes of the cells were unique, which were positive for CD29 and Sca-1, and negative for CD34 and CD45. Cytochemistry evaluation showed that they were homogeneously positive for acid alpha-naphthl acetate esterase (ANAE) and acid phosphatase (ACP), and negative for alkaline phosphatase (ALP) and that, around 5% of them were positive for glycogen (periodic acid-Schiff reaction, PAS). Cells became ALP-positive after the induction by ascorbic acid, beta-phosphoglycerol and dexamethasone. It is concluded that mesenchymal stem cells exist in murine skeletal muscle and compose the complex heterogenous population of stem cells in muscle.

[Cyclosporine A and mycophenolate mofetile as prophylactics for GVHD in a murine model of H-2 haploidentical nonmyeloablative bone marrow transplantation]

In order to research the prophylactic effect of cyclosporine A (CSA) and mycophenolate mofetile (MMF) on GVHD in mice with H-2 haploidentical nonmyeloablative bone marrow transplantation, a murine model was established by using of C57BL/6J mouse as donor and (C57BL/6J x BALB/C) F(1) mouse as the recipient. The recipient mice were given CSA + MTX or CSA + MMF for prophylaxis of acute GVHD (aGVHD). The survival rate, hematopoietic recovery, and morbidity and mortality of aGVHD were observed for 50 days after transplantation. The results showed that typical aGVHD developed in the transplanted mice without prophylactic treatment during 22 to 25 days after transplantation. The morbidity of aGVHD was 75% (15/20), 40% (8/20) and 30% (6/20) and mortality was 100% (15/15), 62.5% (5/8) and 50% (3/6) respectively in unprophylactic group (control), CSA + MTX and CSA + MMF groups. In conclusion, CSA and MTX reduce the morbidity and mortality of aGVHD in mice with haploidentical nonmyeloablative bone marrow transplantation, and the effect of CSA + MMF is better than that of CSA + MTX.

[The investigation of hematopoietic capacity of HPP-CFC derived from murine embryonic stem cells in vitro and in vivo]

The hematopoietic system of the mouse arises from extraembryonic mesoderm that migrate through primitive streak to the presumptive yolk sac at day 7.0 of gestation. However, the mechanisms regulating mesoderm commitment to hematopoietic lineages remain poorly understood. Previous studies demonstrated that the development kinetics and growth factor responsiveness of hematopoietic precursors derived from embryonic stem cells (ES cells) is similar to that found in the yolk sac, indicating that the onset of hematopoiesis within the embryoid bodies (EBs) parallels that found in the embryo. Furthermore, in vitro differentiation of ES cells to hematopoietic cells is valuable for establishment of therapeutic clone against a variety of hematological disorders. Despite the identification of multipotential hematopoietic progenitors in EBs, a subset of more primitive progenitors, identical to the high proliferative potential colony-forming cells (HPP-CFC) derived from human and murine hematopoietic tissues, have not been clearly identified regarding particular their replating potential in vitro. HPP-CFC is among the most primitive hematopoietic multipotent precursors cultured in vitro. In this study, our aim was to investigate the in vitro and in vivo hematopoietic capacity of HPP-CFC within the day 12 EBs, rather than the expansion of more committed progenitors. In this study the HPP-CFC could be detected within EBs differentiated for 5 to 14 days of murine ES cells, but the development dynamics of the HPP-CFC differed greatly among distinct serum lots. Qualitatively HPP-CFC is capable of forming secondary colonies. As to our expectation the ES cells-derived HPP-CFC demonstrated similar regeneration capacity to those from yolk sac, giving rise to secondary granulocyte, erythrocyte, macrophage and mast cells, however largely differed from the counterparts of adult bone marrow. In addition, by RT-PCR ES cells-derived HPP-CFC were found to express transcription factors associated closely with stem cell proliferation including SCL, GATA-2 and AML1 as well as various receptors of hematopoietic growth factors such as c-kit, GM-CSF receptor and interleukin 3 receptor et al. Finally, in order to understand the in vivo hematopoietic capacity of the ES cells-derived HPP-CFC, spleen colony-forming unit (CFU-S) assay was performed. Nevertheless, typical CFU-S was not observed after transplantation of the day 12 EB cells or HPP-CFC colonies into lethally irradiated adult murine. In conclusion the HPP-CFC differentiated from murine ES cells displayed robust hematopoietic activity in vitro, however their in vivo reconstitution ability was not detected. The difference between in vitro and in vivo hematopoietic activities of ES cells-derived primitive hematopoietic precursors deserves further investigation.

[Investigation of in vitro hematopoietic differentiation of embryonic stem cell line established from C57BL/6 mice]

Embryonic hematopoiesis in mammals is characterized by successive temporal and spatial changes. Previous investigations indicate that in vitro differentiation of embryonic stem cells (ES cells) derived from 129 mice can mimic embryonic hematopoiesis to some extent. To investigate the in vitro hematopoietic differentiation capacity of ES cells derived from C57BL/6 mice, the authors initially established the murine ES cell line with standard identification methods employed. Next, two-step culture system was utilized for embryoid bodies formation and the appearance of different hematopoietic precursors was confirmed by CFC assay, cellular chemical staining as well as RT-PCR. The results demonstrated that the ES cell line MES-1 fulfilled the criteria of ES cell line and its progeny after in vitro differentiation included primitive and definitive erythrocyte precursors, mixed colony-forming cells and granulocyte/macrophage colony-forming cells. RT-PCR analysis revealed the molecular consistence of transcription factors and hematopoietic markers with cellular event. In conclusion, MES-1 established from C57BL/6 mice was able to differentiate in vitro to a variety of hematopoietic precursors, thus could partly recapitulate embryonic hematopoiesis.

[Mesenchymal stem cells suppress allogeneic T cell responses by secretion of TGF-beta1]

To investigate the mechanisms underlying the issue that bone marrow mesenchymal stem cells (MSC) could trigger low responsiveness of allogeneic T lymphocytes against alloantigens, phenotypes of T cells were analysed with flow cytometry before and after coculture of allogeneic T lymphocytes with MSC. Further, expression of cytokines including IL-4, IFN-gamma and TGF-beta1 was evaluated by RT-PCR and ELISA as well. The results showed that CD8(+) subpopulation was increased and CD25(+) subset was decreased in proportion after coculture of allogeneic T lymphocytes with MSC for 2 weeks. RT-PCR assay showed that MSC expressed TGF-beta1 but not IL-4 and IFN-gamma, and the result was further proved by ELISA assay showing that the secretion of TGF-beta1 reached to 1 ng/ml in 72 hours. It was concluded that allogeneic MSC suppressed T cells activation by alteration of T cell subpopulations. The suppressive effect was at least in part due to the secretion of TGF-beta1. The results indicate that MSC pretreatment might be useful in the prevention of GVHD in HLA-mismatched bone marrow transplantation and further donors for hematopoietic stem cells could be selected from greater potentials.

[Purification of Human CD40-Ig Fusion Protein and Its Effect on Human Peripheral Blood CFU-T Formation In Virto]

CD40/CD40L interactions play a pivotal role in T cell activation, and take part in many physiologic and pathologic procedures and different levels. In this article, stable CHO transformants secreting human CD40-Ig fusion protein were established through transfection and selection with Lipofectamaine and G418, respectively. In order to obtain great valume of recombinant protein, big batch serum-free cultures of engineered CHO cells were performed in roller-bottle using CHO-II-SFM medium. After cultures, the cell-culture supernatants were harvested, concentrated through ultra-filtration, and finally purified by affinity choromatography with Protein G Sepharose Fast Flow. Human peripheral bloods were collected freshly and seperated with Ficoll, CFU-T was cultured in semi-solid culture system with peripheral blood mononuclear cells (PBMNC). Effect of human CD40-Ig fusion protein on the formation of CFU-T was observed in vitro. The results showed that the yield of human CD40-Ig fusion protein was 30 mg in total 3 liter CHO-II-SFM culture supernatant, and it supposed that the expression level of CD40-Ig in CHO cells was more than 10 micro g/ml. The purity of purified fusion protein is above 95%. Furthermore, compared with human IgG, human CD40-Ig fusion protein significantly inhibited the formation of CFU-T at dose 0.25, 1.0, 4.0, and 10 micro g/ml, it lays a good foundation to evaluate its potential functions in vivo.

[Human Bone Marrow Mesenchymal Stem Cells Differentiate into Neuron-Like Cells In Vitro]

Recent reports have clearly demonstrated that bone marrow cells can be differentiated into neurons, suggesting the existence of cells with the differentiation capacity in the bone marrow cell population. It is well known that hematopoietic stem cells as well as mesenchymal stem cells (MSCs) can be transplanted and therefore, alternative of them might contribute to the process. In the present study it was addressed whether marrow MSCs could be coaxed into neuron-specific antigen bearing cells and if so, whether the differentiated cells possess the cytochemical features seen in neurons. The report here showed that high concentration of 2-mercaptoethanol (2-ME) could induce some of the MSCs into neuron-like cells expressing neurofilament (NF) and neuron specific enolase (NSE). The neuron-like cells were alkaline phosphotase positive while the others MSCs were kept negative. Cells treated with 2-ME were positive for alpha-naphthylacetate esterase and glycogen and negative for acetylchonlinesterase, which were similar with the results seen in untreated cells. Furthermore, Nissel body was not observed in treated cells shown by toluidine blue staining. Therefore, it is likely that the cells described here seem not belong to the neuronal lineage. These findings, however, reveal that human MSCs could alter their committed fates under some circumstances.

Air-liquid interfacial movement in models simulating airway reopening

In this model study, we simulated the initial airway reopening event in a rigid tube model. The air-liquid interface during airway reopening was assumed to be a simple axisymmetric meniscus similar to that of a two-phase flow in a rigid tube (radius R), where the applied pressures and the meniscus velocities were measured experimentally for fluids of different viscosities and surface tensions (gamma). Bulk flow contribution was deducted from the applied pressure to obtain the pressure accounting for interfacial movement (P*(int)). A semi-empirical formula for the interface was generated by dimensional analysis. The dimensionless interfacial pressure (P(int) = P*(int),R/gamma) was found to approach 2 for sufficiently small velocities, consistent with Bretherton's theoretical prediction. This formula also resembles that previously obtained in collapsible tubes simulating airways. The result suggests that the critical pressures required to reopen a collapsible airway and a non-collapsible one with the same radius are similar in magnitude (approximately 2 - 3gamma/R). However, in a collapsible airway, no significant bulk flow of lining fluids would develop while the interface proceeds, leading to a much smaller overall pressure for further reopening. Airway wall collapsibility thus could play a crucial role in maintaining proper ventilation through rapid reopening of the airway.