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Background Nanocarriers-derived antitumor therapeutics are often associated with issues of limited tumor penetration and dissatisfactory antitumor efficacies. Some multistage delivery systems have been constructed to address these issues, but they are often accompanied with complicated manufacture processes and undesirable biocompatibility, which hinder their further application in clinical practices. Herein, a novel dual-responsive multi-pocket nanoparticle was conveniently constructed through self-assembly and cross-linking of amphiphilic methoxypolyethylene glycol-lipoic acid (mPEG-LA) conjugates to enhance tumor penetration and antitumor efficacy. Results The multi-pocket nanoparticles (MPNs) had a relatively large size of ~ 170 nm at physiological pH which results in prolonged blood circulation and enhanced accumulation at the tumor site. But once extravasated into acidic tumor interstices, the increased solubility of PEG led to breakage of the supramolecular nanostructure and dissolution of MPNs to small-sized (3) bearing mice with reduced side effect. Conclusions Our facile fabrication of multi-pocket nanoparticles provided a promising way in improving solid tumor penetration and achieving a great therapeutic efficacy. Graphic Abstract

Congenital coagulation factor V (FV) deficiency is a very rare hemorrhagic disease with an incidence of approximately one in a million. The common clinical manifestations of FV deficiency include ecchymosis and mucosal bleeding. Life-threatening intracranial bleeding is rare. It has been reported in several cases. However, the molecular basis has been established in only a few cases.We reported a 2-month-old girl with congenital FV deficiency and intracranial hemorrhage. Coagulation screening combined with clinical manifestations was performed to diagnose congenital FV deficiency. Genetic testing was performed to identify the pathogenic genes. A literature review was included to emphasize the clinical manifestation, diagnosis, and treatment for congenital FV deficiency with intracranial bleeding.The coagulation tests revealed a significantly prolonged prothrombin time (PT) of 51 s and an activated partial thromboplastin time (APTT) of 73.7 s. The patient had a plasma FV activity of 0.9%. Genetic testing showed compound heterozygous mutations of the patient's FV gene. A literature review showed that patients with homozygous or compound heterozygous variants of the FV gene were often associated with a severe bleeding phenotype.Our study provides a direction for the rapid and accurate diagnosis and treatment for FV deficiency to avoid life-threatening bleeding. Infants with spontaneous cranial hematoma and intracranial hemorrhage should be investigated for underlying hemostatic defects. Congenital coagulation factor deficiency should be considered. Once congenital FV deficiency is diagnosed, fresh frozen plasma (FFP) should be given on a regular basis. Liver transplantation may be performed in severe cases.

Hongli Mao,1 Jinxiu Sheng,1 Jinlin Jia,1 Chang Wang,1 Shanfeng Zhang,2 Hongle Li,3 Fucheng He1 1Department of Medical Laboratory, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, People’s Republic of China; 2The Laboratory Center for Basic Medicine, School of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, People’s Republic of China; 3Department of Molecular Pathology, The Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou, Henan, People’s Republic of ChinaCorrespondence: Fucheng HeDepartment of Medical Laboratory, The First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, Henan, People’s Republic of ChinaEmail hefucheng@zzu.edu.cnBackground: Solute carrier family 6 member 14 (SLC6A14) is a high-capacity amino acid transporter in mammalian cells. It has gained increasing attention for its potential involvement in the progression and metabolic reprogramming of various malignant tumors. However, the role of SLC6A14 in colorectal cancer (CRC) remains unclear.Methods: Real-time polymerase chain reaction (qRT-PCR), immunoblotting and immunohistochemistry were carried out to detect the expression level of SLC6A14 in human CRC tissues and CRC-derived cell lines. HCT-116 and Caco-2 cell lines were selected to conduct in vitro functional studies. Cell Counting Kit-8 (CCK-8), colony formation, flow cytometry, cell migration and invasion assays were performed to investigate the role of SLC6A14 in CRC cells. Besides, azoxymethane/dextran sulfate sodium salt (AOM/DSS)-induced CRC and tumor xenograft models were constructed to explore the effects of SLC6A14 blockade or overexpression during tumor progression in vivo.Results: SLC6A14 was substantially increased in human CRC samples and higher levels of SLC6A14 was correlated with advanced tumor stage, lymph node metastasis and dismal survival of CRC patients. SLC6A14 markedly promoted cell growth, inhibited cell apoptosis, and exacerbated migration and invasion of CRC cells in vitro. Mechanistically, SLC6A14 aggravated these malignant phenotypes through activating JAK2/STAT3 signaling pathway, and inhibiting JAK2/STAT3 signaling with specific inhibitors could reverse SLC6A14-mediated tumorigenic effects. Besides, two different animal studies verified the tumor-promoting effect of SLC6A14 in CRC.Conclusion: Our data illustrated the crucial function of SLC6A14 during CRC progression, suggesting SLC6A14/JAK2/STAT3 axis may serve as novel therapeutic targets for patients with CRC.Keywords: SLC6A14, colorectal cancer, CRC, proliferation, migration, STAT3

3D bioprinting has been developed as a promising technology in a wide variety of biomedical applications. However, the successful implementation of bioprinting is still heavily restricted by the relatively narrow range of printable and biocompatible materials. Recently, many comprehensive reviews of the main bioprinting methods, commonly used bioprinting materials and the trending bioprinting applications have been carried out. In this review, we focused on the trends in the development of materials for 3D bioprinting. The significance and recent advances of ECM-based materials, multi-material and stimuli-responsive materials for bioprinting were summarized successively. Moreover, the challenges in current studies and future perspectives of materials for 3D bioprinting were discussed.

Osteoporosis is a prevalent metabolic bone disease with low bone mass and degenerative disorders of bone tissues. Abnormal osteogenic differentiation of bone marrow mesenchymal stem cells (MSCs) is involved in osteoporosis progression. Nevertheless, the underlying mechanisms for such event are still largely unknown. B7 family member B7H3 plays a critical role in regulating diverse cellular processes, but little is known about its effects on osteoporosis. In our present study, we found that B7H3 expression was down-regulated upon osteogenic induction, and remarkably decreased B7H3 expression was detected in bone marrow derived MSCs from ovariectomized (OVX) mice. Notably, we found that B7H3 conditional knockout (B7H3cKO) in bone marrow MSCs considerably strengthened bone mass in OVX-challenged mice. Loss-of-function experiments indicated that B7H3 ablation remarkably improved the osteogenic differentiation of MSCs both in vitro and in vivo, accompanied by restrained inflammatory response and NF-κB activation. Mechanistically, a direct association between B7H3 and AKT1 was detected. B7H3 deletion strongly up-regulated AKT1 activation in MSCs during osteogenic induction in vitro and in vivo. Further studies suggested that B7H3 knockdown-improved osteogenic differentiation was almost abolished by the blockage of AKT1 activation, demonstrating that B7H3-mediated osteogenic differentiation was largely AKT1-dependent. Together, our results concluded that B7H3 is a critical modulator for osteogenesis of MSCs, and can be a promising therapeutic target for osteoporosis treatment.

Artificial materials have no biological functions, but they are important for medical devices such as artificial organs and matrices for regenerative medicine. In this study, mitogenic and differentiation‐inducible materials are devised via the simple coating of polypeptides, which contain the sequence of epidermal growth factor or insulin‐like growth factor with a key amino acid (3,4‐dihydroxyphenylalanine) of underwater adhesive proteins. The adhesive polypeptides prepared via solid‐phase synthesis form layers on various substrates involving organic and inorganic materials to provide biological surfaces. Through the direct activation of cognate receptors on interactive surfaces, the materials enable increased cell growth and differentiation compared to that achieved by soluble growth factors. This superior growth and differentiation are attributed to the long‐lasting signal transduction (triggered by the bound growth factors), which do not cause receptor internalization and subsequent downregulation., 3,4‐dihydroxyphenylalanine‐containing peptides form bioactive layers on organic and inorganic material surfaces. On the adhesive growth factor nanolayers, cells receive long‐term biological signals from immobilized growth factors, leading to improved cell growth and differentiation.

Additional file 1: Fig. S1. 1H NMR spectrum (400 MHz) of mPEG-LA conjugates in CDCl3. Fig. S2. SEM image (A), size (B) and zeta potential (C) of the self-assembly of mPEG-LA conjugates (NPs, 100 g mL−1). Fig. S3. Size distribution of MPNs at different concentrations. Fig. S4. Fluorescence spectra of a mixed solution of NPs (100 μg mL−1)and MPNs (100 μg mL−1) prepared with 0.1 wt% DiO/DiI tracing the development of FRET between two dyes. Fig. S5. Critical aggregation concentration of MPNs at (A) pH 7.4 or (B) 6.5. Fig. S6. Fluorescence spectra of a mixed solution of MPNs (100 μg mL−1, pH 6.5) prepared with 0.1 wt% DiO/DiI tracing the development of FRET between two dyes over time. Fig. S7. Flow cytometric histogram profiles of 4T1 cells treated with MPNs, DOX, D-NPs and D-MPNs for 3 h (DOX concentration: 10 μg mL−1). Fig. S8. CLSM images of 4T1 cells incubated with DOX, D-NPs, D-MPNs and DOX·HCl for 1 h (DOX dosage: 2 μg mL−1). Hoechst 33342 was used to stain the cell nuclei. Scale bar: 10 μm. Fig. S9. Quantitative assessment of penetration of DOX formulations into 4T1 cells. The cells were incubated with DOX, D-NPs and D-MPNs at a DOX concentration of 5 μg mL−1 for 2 h. Fig. S10. IOD (Integrated optical density) of immunohistochemical images for saline, MPNs, DOX·HCl, D-NPs and D-MPNs groups. The apoptotic rates of tumor sections based on TUNEL images (A), tumor microvessel density based on CD31 images (B) and Ki67 positive cells (C) of tumor sections were calculated with Image-Pro Plus 6.0 software. Data were presented as mean ± SD (n = 3), *p < 0.01, **p < 0.005. Fig. S11. Body weight changes of 4T1-bearing BALB/c mice after administration with saline, MPNs, DOX·HCl, D-NPs and D-MPNs (n = 8, dosage: 5 mg DOX kg−1 mouse body weight, *p < 0.01). The arrows indicated the time points for intravenous injection. Fig. S12. Routine blood analysis results of the mice collected on the 12th day after intravenous injection of saline, MPNs, DOX·HCl, D-NPs or D-MPNs. The results show mean and standard deviation of white blood cells (WBCs), red blood cell (RBC), hemoglobin (HGB) and platelets (PLT). Fig. S13. Histological examination of major organs separated from 4T1-bearing BALB/c mice after administration with saline, MPNs, DOX·HCl, D-NPs and D-MPNs for 18 days. Scale bar: 100 μm. Fig. S14. TUNEL staining of heart (×200) of 4T1-bearing BALB/c mice after administration with saline, MPNs, DOX·HCl, D-NPs and D-MPNs for 18 days. The apoptotic cells (red arrow) and normal cells were stained brown and blue, respectively. Table S1. Pharmacokinetic parameters of DOX·HCl, D-NPs and D-MPNs after intravenous administration at an equivalent dose of 10 mg DOX/kg mouse body weight (n = 3 per group).

Three-dimensional (3D) porous collagen sponges incorporated with single-walled carbon nanotubes (SWCNTs) were prepared and used for 3D culture of bovine articular chondrocytes (BACs). The pore structures of the sponges were controlled by using ice particulates as a porogen material. The responses of cells to SWCNTs were investigated in this 3D cell culture system by evaluation of cell functions and cellular uptake of SWCNTs. The results showed that cells adhered and spatially distributed in the porous sponges. The incorporation of SWCNTs in the porous sponges promoted cell proliferation and production of sulfated glycosaminoglycans (sGAG). Confocal Raman imaging revealed that SWCNTs could be internalized by cells. The hybrid porous sponges not only provided nanostructured pore surfaces to facilitate cell proliferation and extracellular matrix (ECM) secretion but also supplied nanomaterials for cellular uptake which may be useful for biomedical applications.

Carbon nanotubes (CNTs) have shown great potential for biological and medical applications because of their intrinsic unique properties. However, applications of CNTs have been severely restricted by their super-hydrophobicity and easy aggregation in aqueous medium, which are related to cytotoxicity and other negative cellular effects. In this study, single-walled carbon nanotubes (SWCNTs) were functionalized with collagen (collagen-SWCNTs). The collagen-SWCNTs retained the inherent properties of SWCNTs and the suspension solution was stable for months. The cellular effects, uptake and intracellular distribution of the collagen-SWCNTs were investigated by using them for culture of bovine articular chondrocytes (BACs). The collagen-SWCNTs showed no obvious negative cellular effects and high amount of SWCNTs were internalized by cells. The internalized collagen-SWCNTs were distributed in the perinuclear region and retained in the cells for more than one week. Adsorption of SWCNTs by extracellular matrix (ECM) was shown to be an important step for cellular uptake of SWCNTs. The high stability, easy cellular uptake and long retention in cells of the collagen-SWCNTs will facilitate the biomedical and biotechnological applications of SWCNTs.

The biological activity of cell-derived substrates to maintain undifferentiated murine-induced pluripotent stem (iPS) cells was correlated to membrane fluidity as a new parameter of cell culture substrates. Murine embryonic fibroblasts (MEFs) were employed as feeder cells and their membrane fluidity was tuned by chemical fixation using formaldehyde (FA). Membrane fluidity was evaluated by real-time single-molecule observations of green fluorescent protein-labeled epidermal growth factor receptors on chemically fixed MEFs. Biological activity was monitored by colony formation of iPS cells. Treatment with a low concentration of FA sustained the membrane fluidity and biological activity, which were comparable to those of mitomycin C-treated MEFs. The biological activity was further confirmed by sustained expression of alkaline phosphatase, SSEA-1 and other pluripotency markers in iPS cells after 3–5 days of culture on FA-fixed MEFs. Chemical fixation of feeder cells has several advantages such as providing ready-to-use culture substrates without contamination by proliferating feeder cells. Therefore, our results provide an important basis for the development of chemically fixed culture substrates for pluripotent stem cell culture as an alternative to conventional treatment by mitomycin C or x-ray irradiation.

Xiaoyue Zhou,1,2,* Shin-Hye Park,1,* Hongli Mao,3 Takashi Isoshima,1 Yi Wang,2 Yoshihiro Ito1,3 1Nano Medical Engineering Laboratory, RIKEN, Wako, Saitama, Japan; 2Department of Regenerative Medicine, School of Pharmaceutical Sciences, Jilin University, Changchun, Jilin, People’s Republic of China; 3Emergent Bioengineering Materials Research Team, RIKEN Center for Emergent Matter Science, Wako, Saitama, Japan *These authors contributed equally tothis work Abstract: Phosphonated gelatin was prepared for surface modification of titanium to stimulate cell functions. The modified gelatin was synthesized by coupling with 3-aminopropylphosphonic acid using water-soluble carbodiimide and characterized by 31P nuclear magnetic resonance and gel permeation chromatography. Circular dichroism revealed no differences in the conformations of unmodified and phosphonated gelatin. However, the gelation temperature was changed by the modification. Even a high concentration of modified gelatin did not form a gel at room temperature. Time-of-flight secondary ion mass spectrometry showed direct bonding between the phosphonated gelatin and the titanium surface after binding. The binding behavior of phosphonated gelatin on the titanium surface was quantitatively analyzed by a quartz crystal microbalance. Ellipsometry showed the formation of a several nanometer layer of gelatin on the surface. Contact angle measurement indicated that the modified titanium surface was hydrophobic. Enhancement of the attachment and spreading of MC-3T3L1 osteoblastic cells was observed on the phosphonated gelatin-modified titanium. These effects on cell adhesion also led to growth enhancement. Phosphonation of gelatin was effective for preparation of a cell-stimulating titanium surface. Keywords: phosphonated gelatin, surface modification, titanium, cell adhesion