Search

This exploration is to solve the efficiency and accuracy of cell recognition in biological experiments. Neural network technology is applied to the research of cell image recognition. The cell image recognition problem is solved by constructing an image recognition algorithm. First, with an in-depth understanding of computer functions, as a basic intelligent algorithm, the artificial neural network (ANN) is widely used to solve the problem of image recognition. Recently, the backpropagation neural network (BPNN) algorithm has developed into a powerful pattern recognition tool and has been widely used in image edge detection. Then, the structural model of BPNN is introduced in detail. Given the complexity of cell image recognition, an algorithm based on the ANN and BPNN is used to solve this problem. The BPNN algorithm has multiple advantages, such as simple structure, easy hardware implementation, and good learning effect. Next, an image recognition algorithm based on the BPNN is designed and the image recognition process is optimized in combination with edge computing technology to improve the efficiency of algorithm recognition. The experimental results show that compared with the traditional image pattern recognition algorithm, the recognition accuracy of the designed algorithm for cell images is higher than 93.12%, so it has more advantages for processing the cell image algorithm. The results show that the BPNN edge computing can improve the scientific accuracy of cell recognition results, suggesting that edge computing based on the BPNN has a significant practical value for the research and application of cell recognition.

Coronavirus disease 2019 (COVID-19) treatments are still urgently needed for critically and severely ill patients. Human umbilical cord-mesenchymal stem cells (hUC-MSCs) infusion has therapeutic benefits in COVID-19 patients; however, uncertain therapeutic efficacy has been reported in severe patients. In this study, we selected an appropriate cytokine, IL-18, based on the special cytokine expression profile in severe pneumonia of mice induced by H1N1virus to prime hUC-MSCs in vitro and improve the therapeutic effect of hUC-MSCs in vivo. In vitro, we demonstrated that IL-18-primed hUC-MSCs (IL18-hUCMSC) have higher proliferative ability than non-primed hUC-MSCs (hUCMSCcon), and there was no significant difference in their migration capacity. In addition, VCAM-1, MMP-1, TGF-β1, and some chemokines (CCL2 and CXCL12, for example) are more highly expressed in IL18-hUCMSCs. We found that IL18-hUCMSC significantly enhanced the immunosuppressive effect on CD3+ T-cells. In vivo, we demonstrated that IL18-hUCMSC infusion could reduce the body weight loss caused by a viral infection and significantly improve the survival rate. Of note, IL18-hUCMSC can also significantly attenuate certain clinical symptoms, including reduced activity, ruffled fur, hunched backs, and lung injuries. Pathologically, IL18-hUCMSC transplantation significantly enhanced the inhibition of inflammation, viral load, fibrosis, and cell apoptosis in acute lung injuries. Notably, IL18-hUCMSC treatment has a superior inhibitory effect on T-cell exudation and proinflammatory cytokine secretion in bronchoalveolar lavage fluid (BALF). Altogether, IL-18 is a promising cytokine that can prime hUC-MSCs to improve the efficacy of precision therapy against viral-induced pneumonia, such as COVID-19.

Background Pulmonary fibrosis (PF) is a growing clinical problem with limited therapeutic options. Human umbilical cord mesenchymal stromal cell (hucMSC) therapy is being investigated in clinical trials for the treatment of PF patients. However, little is known about the underlying molecular and cellular mechanisms of hucMSC therapy on PF. In this study, the molecular and cellular behavior of hucMSC was investigated in a bleomycin-induced mouse PF model. Methods The effect of hucMSCs on mouse lung regeneration was determined by detecting Ki67 expression and EdU incorporation in alveolar type 2 (AT2) and lung fibroblast cells. hucMSCs were transfected to express the membrane localized GFP before transplant into the mouse lung. The cellular behavior of hucMSCs in mouse lung was tracked by GFP staining. Single cell RNA sequencing was performed to investigate the effects of hucMSCs on gene expression profiles of macrophages after bleomycin treatment. Results hucMSCs could alleviate collagen accumulation in lung and decrease the mortality of mouse induced by bleomycin. hucMSC transplantation promoted AT2 cell proliferation and inhibited lung fibroblast cell proliferation. By using single cell RNA sequencing, a subcluster of interferon-sensitive macrophages (IFNSMs) were identified after hucMSC infusion. These IFNSMs elevate the secretion of CXCL9 and CXCL10 following hucMSC infusion and recruit more Treg cells to the injured lung. Conclusions Our study establishes a link between hucMSCs, macrophage, Treg, and PF. It provides new insights into how hucMSCs interact with macrophage during the repair process of bleomycin-induced PF and play its immunoregulation function.

Oncogenic RAS is a critical driver for the initiation and progression of several types of cancers. However, effective therapeutic strategies by targeting RAS, in particular RASG12D and RASG12V, and associated downstream pathways have been so far unsuccessful. Treatment of oncogenic RAS-ravaged cancer patients remains a currently unmet clinical need. Consistent with a major role in cancer metabolism, oncogenic RAS activation elevates both reactive oxygen species (ROS)-generating NADPH oxidase (NOX) activity and ROS-scavenging glutathione biosynthesis. At a certain threshold, the heightened oxidative stress and antioxidant capability achieve a higher level of redox balance, on which cancer cells depend to gain a selective advantage on survival and proliferation. However, this prominent metabolic feature may irrevocably render cancer cells vulnerable to concurrent inhibition of both NOX activity and glutathione biosynthesis, which may be exploited as a novel therapeutic strategy. In this report, we test this hypothesis by treating the HRASG12V-transformed ovarian epithelial cells, mutant KRAS-harboring pancreatic and colon cancer cells of mouse and human origins, as well as cancer xenografts, with diphenyleneiodonium (DPI) and buthionine sulfoximine (BSO) combination, which inhibit NOX activity and glutathione biosynthesis, respectively. Our results demonstrate that concomitant targeting of NOX and glutathione biosynthesis induces a highly potent lethality to cancer cells harboring oncogenic RAS. Therefore, our studies provide a novel strategy against RAS-bearing cancers that warrants further mechanistic and translational investigation.

Peripheral blood mononuclear cells are widely used as source material for anticancer immunotherapies. The conventional cryopreservation method for peripheral blood mononuclear cells is time-consuming and expansive, which involves controlled rate freezing followed by storage in liquid nitrogen. Instead, the convenient uncontrolled rate freezing cryopreservation method had been reported successfully in peripheral blood hematopoietic stem cells and peripheral blood progenitor cells. Therefore, we hypothesized that uncontrolled rate freezing cooling method maybe also applied to peripheral blood mononuclear cells cryopreservation. In this study, we evaluated the performance of uncontrolled rate freezing and controlled rate freezing cooling methods through cell recovery rate, viability, differentiation potential into cytokine-induced killer cells and the cellular properties of the cultured cytokine-induced killer cells. The results showed similar post-thaw viability and recovery rate in both controlled rate freezing and uncontrolled rate freezing cryopreserved peripheral blood mononuclear cells. Importantly, the uncontrolled rate freezing cryopreserved peripheral blood mononuclear cells exhibited higher growth ratio and earlier cell clustering during ex-vivo cytokine-induced killer cell culture than the controlled rate freezing ones. These two groups of expanded cytokine-induced killer cells also exhibited similar effector cell subset ratio and tumoricidal activity. In general, the performance of cryopreserved peripheral blood mononuclear cells using uncontrolled rate freezing cooling method, with the commercial cryoprotective agent CellBanker 2, was equal or better than the controlled rate freezing method. Our study implied that the combined use of cryoprotective agent CellBanker 2 and uncontrolled rate freezing could be a convenient cryopreservation method for peripheral blood mononuclear cells.

The current work aims to strengthen the research of segmentation, detection, and tracking methods of stem cell image in the fields of regenerative medicine and tissue damage restoration. Firstly, based on the relevant theories of stem cell image segmentation, digital twins (DTs), and lightweight deep learning, a new phase contrast microscope is introduced through the research of optical microscope. Secondly, the results of DTs method and phase contrast imaging principle are compared in stem cell image segmentation and detection. Finally, a lightweight deep learning model is introduced in the segmentation and tracking of stem cell image to observe the gray value and mean value before and after stem cell image movement and stem cell division. The results show that phase contrast microscope can increase the phase contrast and amplitude difference of stem cell image and solve the problem of stem cell image segmentation to a certain extent. The detection results of DTs method are compared with phase contrast imaging principle. It indicates that not only can DTs method make the image contour more accurate and clearer, but also its accuracy, recall, and F1 score are 0.038, 0.024, and 0.043 higher than those of the phase contrast imaging method. The lightweight deep learning model is applied to the segmentation and tracking of stem cell image. It is found that the gray value and mean value of stem cell image before and after movement and stem cell division do not change significantly. Hence, the application of DTs and lightweight deep learning methods in the segmentation, detection, and tracking of stem cell image has great reference significance for the development of biology and medicine.

Mesenchymal stromal cells (MSCs) show potential for treating preclinical models of newborn bronchopulmonary dysplasia (BPD), but studies of their therapeutic effectiveness have had mixed results, in part due to the use of different media supplements for MSCs expansion in vitro. The current study sought to identify an optimal culture supplement of umbilical cord-derived MSCs (UC-MSCs) for BPD therapy. In this study, we found that UC-MSCs cultured with human platelet lysate (hPL-UCMSCs) were maintained a small size from Passage 1 (P1) to P10, while UC-MSCs cultured with fetal bovine serum (FBS-UCMSCs) became wide and flat. Furthermore, hPL was associated with lower levels of senescence in UC-MSCs during in vitro expansion compared with FBS, as indicated by the results of β-galactosidase staining and measures of senescence-related genes (CDKN2A, CDKN1A, and mTOR). In addition, hPL enhanced the proliferation and cell viability of the UC-MSCs and reduced their doubling time in vitro. Compared with FBS-UCMSCs, hPL-UCMSCs have a greater potential to differentiate into osteocytes and chondrocytes. Moreover, using hPL resulted in greater expression of Nestin and specific paracrine factors (VEGF, TGF-β1, FGF2, IL-8, and IL-6) in UC-MSCs compared to using FBS. Critically, we also found that hPL-UCMSCs are more effective than FBS-UCMSCs for the treatment of BPD in a rat model, with hPL leading to improvements in survival rate, lung architecture and fibrosis, and lung capillary density. Finally, qPCR of rat lung mRNA demonstrated that hPL-UCMSCs had lower expression levels of inflammatory factors (TNF-α and IL-1β) and a key chemokine (MCP-1) at postnatal day 10, and there was significant reduction of CD68+ macrophages in lung tissue after hPL-UCMSCs transplantation. Altogether, our findings suggest that hPL is an optimal culture supplement for UC-MSCs expansion in vitro, and that hPL-UCMSCs promote lung repair in rat BPD disease.

In this study, we compared three commercially available and two widely used CPAs for their ability of cryopreserving PBMCs. Similar survival (81.0%) and recovery rate (73.7%) were observed among cells using these five CPAs. However, all the cryopreserved PBMCs exhibited a significantly lower survival rate when compared with the fresh samples (94.3%). We further evaluated effector cell subpopulation and tumoricidal activity of PBMC-derived cytokine-induced killing (CIK) cells and natural killing (NK) cells. Similar and high survival (CIK: 88.6%; NK: 87.5%) and recovery (CIK: 99.5%; NK: 99.7%) rates were detected in CIK and NK cells prepared from cryopreserved PBMCs using the five CPAs. The CD3+CD56+ effector percentage (27.3%) of cryopreserved PBMC-derived CIK cells using the five different CPAs and their tumoricidal activities on melanoma CHL-1 cells (45.7%) and bladder cancer cell line T-24 (44.7%) were similar but significantly lower than those of the fresh PBMC-derived controls (effector: 30.7%; CHL-1: 84.2%; T-24: 82.2%). Cryopreserved PBMC-derived NK cells also exhibited similar tumoricidal activities (CHL-1: 73.8%; T-24: 71.9%) but was significantly lower than that of the fresh control group. We were not able to identify a specific CPA that performed superior than others in PBMC cryopreservation.

Background：Pulmonary fibrosis (PF) is a growing clinical problem with limited therapeutic options. Human umbilical cord mesenchymal stromal cell (hucMSC) therapy is being investigated in clinical trials for the treatment of PF patients. However, little is known about the underlying molecular and cellular mechanisms of hucMSC therapy on PF. In this study, the molecular and cellular behavior of hucMSC was investigated in a bleomycin induced mouse PF model. Methods: The effect of hucMSC on mouse lung regeneration was determined by detecting Ki67 expression and Edu incorporation in alveolar type 2 (AT2) and lung fibroblast cells. The hucMSC was transfected to express the membrane localized GFP before transplant into the mouse lung. The cellular behavior of hucMSC in mouse lung was tracked by GFP staining. Single cell RNA sequencing was performed to investigate the molecular mechanism of hucMSC on PF. Results: hucMSCs could alleviate collagen accumulation in lung and decrease the mortality of mouse induced by bleomycin. hucMSCs transplantation promoted AT2 cell proliferation and inhibited lung fibroblast cell proliferation. Mouse lung macrophage phenotype was changed after interacting with hucMSCs. By using single-cell RNA sequencing, a subcluster of interferon-sensitive macrophages were identified after hucMSC infusion. These macrophages elevate the secretion of CXCL9 and CXCL10 following hucMSC infusion and recruit more Treg cells to the injured lung. Conclusions: Our study establishes a link between hucMSCs, macrophage proliferation, and PF with potential applications in PF therapeutics. It provides new insights into how hucMSCs interact with macrophage during the repair process of bleomycin-induced PF and play its immunoregulation function.

KRAS mutations are prevalent in patients with pancreatic ductal adenocarcinoma (PDAC) and are critical to fostering tumor growth in part by aberrantly rewiring glucose, amino acid, and lipid metabolism. Obesity is a modifiable risk factor for pancreatic cancer. Corroborating this epidemiological observation, mice harboring mutant KRAS are highly vulnerable to obesogenic high-fat diet (HFD) challenges leading to the development of PDAC with high penetrance. However, the contributions of other macronutrient diets, such as diets rich in carbohydrates that are regarded as a more direct source to fuel glycolysis for cancer cell survival and proliferation than HFD, to pancreatic tumorigenesis remain unclear. In this study, we compared the differential effects of a high-carbohydrate diet (HCD), an HFD, and a high-protein diet (HPD) in PDAC development using a mouse model expressing an endogenous level of mutant KRASG12D specifically in pancreatic acinar cells. Our study showed that although with a lower tumorigenic capacity than chronic HFD, chronic HCD promoted acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN) lesions with increased inflammation, fibrosis, and cell proliferation compared to the normal diet (ND) in KrasG12D/+ mice. By contrast, chronic HPD showed no significant adverse effects compared to the ND. Furthermore, ablation of pancreatic acinar cell cyclooxygenase 2 (Cox-2) in KrasG12D/+ mice abrogated the adverse effects induced by HCD, suggesting that diet-induced pancreatic inflammation is critical for promoting oncogenic KRAS-mediated neoplasia. These results indicate that diets rich in different macronutrients have differential effects on pancreatic tumorigenesis in which the ensuing inflammation exacerbates the process. Management of macronutrient intake aimed at thwarting inflammation is thus an important preventive strategy for patients harboring oncogenic KRAS.

Mesenchymal stem cells (MSC) are a popular candidate in cellular therapy for many diseases. MSCs are well known by their feature of self-renewal and their differentiation potential. NESTIN is a cytoskeletal protein expressed in MSC that functions directly in cell proliferation and differentiation. Here, we demonstrated that adding UltraGRO, a medium supplement, could maintain and partially recover the expression of NESTIN in human umbilical cord derived MSCs (UC-MSCs). Furthermore, the UC-MSCs cultured with UltraGRO showed a better immunomodulation ability in a colitis mouse model compared with those cultured in other types of media. This indicates that the use of novel culture medium benefits the maintenance of NESTIN expression and NESTIN may be one of the vital factors that regulates the performance of MSCs.

Mesenchymal stem cells (MSCs) are a promising cell resource for the treatment of ischemic diseases, partially through paracrine effects. One of the major obstacles of MSC treatment is the poor survival rate and low efficiency of transplanted stem cells due to ischemic or inflammatory environments. Gremlin1 (GREM1), a regulator of growth, differentiation and development, has been identified as a novel proangiogenic factor. However, the role and mechanism of GREM1 in MSCs remains unclear. Therefore, we assessed the putative beneficial effects of GREM1 on MSC-based therapy for hindlimb ischemia. The lentiviral vector, EF1a-GREM1, was constructed using the Multisite Gateway System and used to transduce MSCs. In vitro studies demonstrated increased survival of GREM1-MSCs exposed to H2 O2 , which is consistent with the activation of caspase-3. Conditional medium from GREM1-MSCs (GREM1-MSC-CM) increased the anti-apoptotic effects of human umbilical vein endothelial cells (HUVECs), and this effect was attenuated by treatment with the PI3K/Akt pathway inhibitor LY294002. MSCs modified with GREM1 could significantly increase blood perfusion of the ischemic hindlimb in vivo in a mouse model, which was correlated to improved MSC survival. This study demonstrates that overexpression of GREM1 in MSCs have greater therapeutic effects against ischemia compared with wild-type MSCs by enhancing the survival of MSCs and ECs, which may provide new tools for studies investigating the treatment of ischemic diseases. J. Cell. Physiol. 232: 996-1007, 2017. © 2016 Wiley Periodicals, Inc.

Mesenchymal stromal cells (MSCs) have shown great potential for treating inflammatory bowel disease, which is ameliorated through paracrine cross talk between MSCs and T-cells. Members of the insulin-like growth factor binding protein (IGFBP) family have important immunomodulatory functions in MSCs, but the underlying mechanisms behind these functions have not yet been clearly elucidated. In this study, we investigate whether MSC-produced IGFBP7 is involved in immune modulation using a mouse experimental colitis model. Gene expression profiling revealed that IGFBP7 was highly expressed in MSCs. Consistent with this findings, IGFBP7 knockdown in MSCs significantly decreased their immunomodulatory properties, decreasing the antiproliferative functions of MSCs against T-cells, while also having an effect on the proinflammatory cytokine production of the T-cells. Furthermore, in the mouse experimental colitis model, MSC-derived IGFBP7 ameliorated the clinical and histopathological severity of induced colonic inflammation and also restored the injured gastrointestinal mucosal tissues. In conclusion, IGFBP7 contributes significantly to MSC-mediated immune modulation, as is shown by the ability of IGFBP7 knockdown in MSCs to restore proliferation and cytokine production in T-cells. These results suggest that IGFBP7 may act as a novel MSC-secreted immunomodulatory factor.

Mesenchymal stem cells (MSCs) have recently been shown to home to tumors and contribute to the formation of the tumor-associated stroma. In addition, MSCs can secrete paracrine factors to facilitate tumor progression. However, the involvement of MSC-derived cytokines in colorectal cancer (CRC) angiogenesis and growth has not been clearly addressed. In this study, we report that interleukin-8 (IL-8) was the most highly upregulated pro-angiogenic factor in MSCs co-cultured with CRC cells and was expressed at substantially higher levels in MSCs than CRC cells. To evaluate the effect of MSC-derived IL-8 on CRC angiogenesis and growth, we used MSCs that expressed small hairpin (interfering) RNAs (shRNA) targeting IL-8 (shIL-8-MSCs). We found that MSC-secreted IL-8 promoted human umbilical vein endothelial cell (HUVEC) proliferation and migration, tube-formation ability and CRC cell proliferation. Additionally, in vivo studies showed that MSCs promoted tumor angiogenesis partially through IL-8. Taken together, these findings suggest that IL-8 secreted by MSCs promotes CRC angiogenesis and growth and can therefore serve as a potential novel therapeutic target.

Various strategies have been proposed for the detection of disease protein biomarkers; however, most methods are too expensive, cumbersome or limited in sensitivity for clinical use. Here, we report that a fabricated complex can be used as a powerful tool to detect trace proteins in complex samples. In this strategy, a DNA–protein complex that comprises of one target molecule and two or more deoxyribozyme-containing probes can exhibit autonomous cleavage behavior on the surface of the substrate DNA modified electrode. In the meantime, the complex can remove the cleaved DNA fragment from the electrode surface by taking advantage of the proximity effect. The proposed approach allows one-step and highly sensitive detection of a variety of targets based on the changes of the direct electrochemical readout. Moreover, this method may also have considerable advantages over the commonly reported DNA amplification-assisted immunoassays, particularly in terms of assay simplicity and cost, which may hold great potential for application in resource-constrained regions.

Although mesenchymal stromal cells (MSCs) possess immunomodulatory properties and exhibit promising efficacy against chronic graft-versus-host disease (cGVHD), little is known about the immune changes by which MSCs ameliorate cGVHD in vivo. Recent studies have suggested that B lymphocytes might play an important role in the pathogenesis of cGVHD. In this study, we investigated changes in the numbers, phenotypes, and subpopulations of B lymphocytes in cGVHD patients who showed a complete response (CR), partial response (PR), or no response (NR) after MSC treatment. We found that the frequencies and numbers of CD27+ memory and pre-germinal center B lymphocytes were significantly increased in the CR and PR cGVHD patients after MSC treatment but decreased in the NR patients. A further analysis of CR/PR cGVHD patients showed that MSC treatment led to a decrease in the plasma levels of B cell-activating factor (BAFF) and increased expression of the BAFF receptor (BAFF-R) on peripheral B lymphocytes but no changes in plasma BAFF levels or BAFF-R expression on B lymphocytes in NR patients. Overall, our findings imply that MSCs might exert therapeutic effects in cGVHD patients, accompanied by alteration of naïve and memory B-cell subsets, modulating plasma BAFF levels and BAFF-R expression on B lymphocytes.

Neural stem cells (NSCs) migration is essential for neurogenesis and neuroregeneration after brain injury. Nestin, a widely used marker of NSCs, is expressed abundantly in several cancers, where it may correlate with tumor migration and invasion. However, it is not yet known whether nestin participates in NSC migration. Here, we show that nestin down-regulation significantly inhibits the migration and contraction of murine neural stem cells, but does not obviously influence the proliferation, filamentous actin (F-actin) content, distribution or focal adhesion assembly of these cells. Mechanistically, nestin knockdown was found to affect the phosphorylation state of myosin regulatory light chain (MRLC) and regulate the activity of myosin light chain kinase (MLCK). Co-immunoprecipitation experiments showed that it interacts with MLCK and MRLC. Together, our results indicate that nestin may increase NSC motility via elevating MLCK activity through direct binding and provide new insight into the roles of nestin in NSC migration and repair.

Supplementary material online. Methods. (DOC 79 kb)

To investigate the immumodulation ability of exosomes secreted from human umbilical cord-derived mesenchymal stem cells (hUC-MSCs).hUC-MSCs were isolated and cultured.Exosomes were isolated from the culture media of the third-generation hUC-MSCs. The expression of specific surface marker CD9 and CD81 were detected by Western blot, and the concentration of hUC-MSCs exosomes(hUC-MSCs-ex) was evaluated by BCA assay. CD3/CD28-stimulated peripheral blood mononuclear cells(PBMCs) from healthy donor were co-cultured with different concentration of hUC-MSCs-ex for 72 h. The percentage of Th17 and Treg cells and the proliferation of CD4⁺ and CD8⁺ T cells were detected by flow cytometry. ELISA was used to test the level of IFN-γ, IL-6, TNF-α and TGF-β1.hUC-MSCs-ex inhibited the proliferation of CD4⁺ and CD8⁺ cells obviously,and increased the proportion of CD4⁺ CD25⁺ FoxP3⁺ Treg cells, with high expression of CD81 and CD9. After CD3/CD28 monoclonal antibody stimulated, the percentage of CD45⁺ CD4⁺ Ki67⁺ and CD45⁺ CD8⁺ Ki67⁺ cells were 85.3% ± 5.6% and 72.6% ± 6.3%, respectively. Meanwhile, the level of TGF-β1 were elevated and the level of IFN-γ, IL-6 and TNF-α were decreased (P0.05).hUC-MSCs-ex has the immunomodulatory functionin vitro, which could be a new therapeutic agent for the treatment of immune disorders.

Rational utilization of nanomaterials to construct electrochemical nucleic acid sensors has attracted large attention in recent years. In this work, we systematically interrogate the interaction between gold nanoparticles (GNPs) and single-strand DNA (ssDNA) immobilized on an electrode surface and then take advantage of the ultrahigh charge-transfer efficiency of GNPs to develop a novel DNA sensing method. Specifically, ssDNA modified gold electrode can adsorb GNPs because of the interaction between gold and nitrogen-containing bases; thus, the negative electrochemical species [Fe(CN)6](3-/4-) may transfer electrons to electrode through adsorbed GNPs. In the presence of target DNA, the formed double-strand DNA (dsDNA) cannot capture GNPs onto the electrode surface and the dsDNA may result in a large charge-transfer resistance owing to the negatively charged phosphate backbones of DNA. So a simple but sensitive method for the detection of target DNA can be developed by using GNPs without any requirement of modification. Experimental results demonstrate that the electrochemical method we have proposed in this work can detect as low as 1 pM breast cancer gene BRCA1 in a 10 μL sample volume without any signal amplification process or the involvement of other synthesized complex, which may provide an alternative for cancer DNA detection. This method may also be generalized for detecting a spectrum of targets using functional DNA (aptamer, metal-specific oligonucleotide, or DNAzyme) in the future.

Background Interstitial pneumonia in connective tissue diseases (CTD-IP) featuring inflammation and fibrosis is a leading cause of death in CTD-IP patients. The related autoimmune lung injury and disturbed self-healing process make conventional anti-inflammatory drugs ineffective. Equipped with unique immunoregulatory and regenerative properties, mesenchymal stem cells (MSCs) may represent a promising therapeutic agent in CTD-IP. In this study, we aim to define the immunopathology involved in pulmonary exacerbation during autoimmunity and to determine the potential of MSCs in correcting these disorders. Methods Lung and blood specimens, bronchoalveolar lavage fluid cells collected from CTD-IP patients, and human primary lung fibroblasts (HLFs) from patients pathologically diagnosed with usual interstitial pneumonia (UIP) and healthy controls were analyzed by histology, flow cytometry and molecular biology. T cell subsets involved in the process of CTD-IP were defined, while the regulatory functions of MSCs isolated from the bone marrow of normal individuals (HBMSCs) on cytotoxic T cells and CTD-UIP HLFs were investigated in vitro. Results Higher frequencies of cytotoxic T cells were observed in the lung and peripheral blood of CTD-IP patients, accompanied with a reduced regulatory T cell (Treg) level. CTD-UIP HLFs secreted proinflammatory cytokines in combination with upregulation of α-smooth muscle actin (α-SMA). The addition of HBMSCs in vitro increased Tregs concomitant with reduced cytotoxic T cells in an experimental cell model with dominant cytotoxic T cells, and promoted Tregs expansion in T cell subsets from patients with idiopathic pulmonary fibrosis (IPF). HBMSCs also significantly decreased proinflammatory chemokine/cytokine expression, and blocked α-SMA activation in CTD-UIP HLFs through a TGF-β1-mediated mechanism, which modulates excessive IL-6/STAT3 signaling leading to IP-10 expression. MSCs secreting a higher level of TGF-β1 appear to have an optimal anti-fibrotic efficacy in BLM-induced pulmonary fibrosis in mice. Conclusions Impairment of TGF-β signal transduction relevant to a persistent IL-6/STAT3 transcriptional activation contributes to reduction of Treg differentiation in CTD-IP and to myofibroblast differentiation in CTD-UIP HLFs. HBMSCs can sensitize TGF-β1 downstream signal transduction that regulates IL-6/STAT3 activation, thereby stimulating Treg expansion and facilitating anti-fibrotic IP-10 production. This may in turn block progression of lung fibrosis in autoimmunity.