In vivo tumor-targeted dual-modal fluorescence/CT imaging using a nanoprobe co-loaded with an aggregation-induced emission dye and gold nanoparticles

As an intensely studied computed tomography (CT) contrast agent, gold nanoparticle has been suggested to be combined with fluorescence imaging modality to offset the low sensitivity of CT. However, the strong quenching of gold nanoparticle on fluorescent dyes requires complicated design and shielding to overcome. Herein, we report a unique nanoprobe (M-NPAPF-Au) co-loading an aggregation-induced emission (AIE) red dye and gold nanoparticles into DSPE-PEG₂₀₀₀ micelles for dual-modal fluorescence/CT imaging. The nanoprobe was prepared based on a facile method of “one-pot ultrasonic emulsification”. Surprisingly, in the micelles system, fluorescence dye (NPAPF) efficiently overcame the strong fluorescence quenching of shielding-free gold nanoparticles and retained the crucial AIE feature. In vivo studies demonstrated the nanoprobe had superior tumor-targeting ability, excellent fluorescence and CT imaging effects. The totality of present studies clearly indicates the significant potential application of M-NPAPF-Au as a dual-modal non-invasive fluorescence/X-ray CT nanoprobe for in vivo tumor-targeted imaging and diagnosis.     

Myelin repair in vivo is increased by targeting oligodendrocyte precursor cells with nanoparticles encapsulating leukaemia inhibitory factor (LIF)

Multiple sclerosis (MS) is a progressive demyelinating disease of the central nervous system (CNS). Many nerve axons are insulated by a myelin sheath and their demyelination not only prevents saltatory electrical signal conduction along the axons but also removes their metabolic support leading to irreversible neurodegeneration, which currently is untreatable. There is much interest in potential therapeutics that promote remyelination and here we explore use of leukaemia inhibitory factor (LIF), a cytokine known to play a key regulatory role in self-tolerant immunity and recently identified as a pro-myelination factor. In this study, we tested a nanoparticle-based strategy for targeted delivery of LIF to oligodendrocyte precursor cells (OPC) to promote their differentiation into mature oligodendrocytes able to repair myelin. Poly(lactic-co-glycolic acid)-based nanoparticles of ∼120 nm diameter were constructed with LIF as cargo (LIF-NP) with surface antibodies against NG-2 chondroitin sulfate proteoglycan, expressed on OPC. In vitro, NG2-targeted LIF-NP bound to OPCs, activated pSTAT-3 signalling and induced OPC differentiation into mature oligodendrocytes. In vivo, using a model of focal CNS demyelination, we show that NG2-targeted LIF-NP increased myelin repair, both at the level of increased number of myelinated axons, and increased thickness of myelin per axon. Potency was high: a single NP dose delivering picomolar quantities of LIF is sufficient to increase remyelination.Impact statementNanotherapy-based delivery of leukaemia inhibitory factor (LIF) directly to OPCs proved to be highly potent in promoting myelin repair in vivo: this delivery strategy introduces a novel approach to delivering drugs or biologics targeted to myelin repair in diseases such as MS.     

Vascular endothelial growth factor receptor 1 (VEGFR1) tyrosine kinase signaling facilitates granulation tissue formation with recruitment of VEGFR1<Superscript>+</Superscript> cells from bone marrow

Vascular endothelial growth factor (VEGF)-A facilitates wound healing. VEGF-A binds to VEGF receptor 1 (VEGFR1) and VEGFR2 and induces wound healing through the receptor’s tyrosine kinase (TK) domain. During blood flow recovery and lung regeneration, expression of VEGFR1 is elevated. However, the precise mechanism of wound healing, especially granulation formation on VEGFR1, is not well understood. We hypothesized that VEGFR1-TK signaling induces wound healing by promoting granulation tissue formation. A surgical sponge implantation model was made by implanting a sponge disk into dorsal subcutaneous tissue of mice. Granulation formation was estimated from the weight of the sponge and the granulation area from the immunohistochemical analysis of collagen I. The expression of fibroblast markers was estimated from the expression of transforming growth factor-beta (TGF-β) and cellular fibroblast growth factor-2 (FGF-2) using real-time PCR (polymerase chain reaction) and from the immunohistochemical analysis of S100A4. VEGFR1 TK knockout (TK^?/?) mice exhibited suppressed granulation tissue formation compared to that in wild-type (WT) mice. Expression of FGF-2, TGF-β, and VEGF-A was significantly suppressed in VEGFR1 TK^?/? mice, and the accumulation of VEGFR1⁺ cells in granulation tissue was reduced in VEGFR1 TK^?/? mice compared to that in WT mice. The numbers of VEGFR1⁺ cells and S100A4⁺ cells derived from bone marrow (BM) were higher in WT mice transplanted with green fluorescent protein (GFP) transgenic WT BM than in VEGFR1 TK^?/? mice transplanted with GFP transgenic VEGFR1 TK^?/? BM. These results indicated that VEGFR1-TK signaling induced the accumulation of BM-derived VEGFR1⁺ cells expressing F4/80 and S100A4 and contributed to granulation formation around the surgically implanted sponge area in a mouse model.     

Silymarin amplifies apoptosis in ectopic endometrial tissue in rats with endometriosis; implication on growth factor GDNF,ERK1/2 and Bcl-6b expression

The present prospective study was done to evaluate the effect of silymarin (SMN) on endometriotic-like legions establishment and growth in experimentally-induced endometriosis. For this purpose, the experimental endometriosis was induced in 12 rats and then the animals subdivided into endometriosis-sole and SMN (50?mg?kg^?1, orally)+endometriosis groups. Following 28 days, the legions establishment, size, Glial cell line-derived neurotrophic factor (GDNF), gfrα1, B Cell Lymphoma 6 (Bcl-6b), Bcl-2, extracellular regulator kinase (ERK1/2) expression ratios, angiogenesis, the apoptosis and fibrosis indices were investigated. The SMN significantly (P?<?0.05) decreased the enometriotic-like legions establishment and size, decreased mRNA levels of GDNF, gfrα1, Bcl-6b and Bcl-2 and remarkably diminished GDNF, gfrα1, Bcl-6b and Bcl-2-positive cells distribution/mm² of tissue versus endometriosis-sole group. The SMN?+?endometriosis group exhibited a significant (P?<?0.05) enhancement in ERK1/2 expression and represented diminished vascularized area and increased apoptosis and fibrosis indices, as well. In conclusion, the SMN by down-regulating GDNF and its receptor gfrα1 expression inhibits GDNF-gfrα1 complex generation and consequently suppresses Bcl-6b expression. Moreover, the SMN by enhancing the ERK1/2 expression and by suppressing the Bcl-2 expression promotes the apoptosis pathway. Finally, the SMN by down-regulating the angiogenesis ratio accelerates apoptosis and consequently induces severe fibrosis in endometriotic-like legions.     

Intimal sarcoma of the abdominal aorta with platelet‐derived growth factor receptor α overexpression and amplification in mural invasive cells and pulmonary metastatic cells but not in intimal spreading cells

Intimal sarcoma (IS) is the most common sarcoma of the aorta. The platelet‐derived growth factor receptor α (PDGFRA), murine double minute 2 (MDM2), and cyclin‐dependent kinase 4 (CDK4) genes are often simultaneously amplified in IS. While immunohistochemical analysis of IS tissue has demonstrated frequent overexpression of the MDM2 and CDK4 proteins, the expression pattern of PDGFRA has not been well characterized, particularly in terms of intratumoral heterogeneity. Here, we present the case of a 46‐year‐old man who presented with a backache and was subsequently diagnosed with IS. Intratumoral heterogeneity of PDGFRA gene amplification was observed using fluorescence in situ hybridization and was positively correlated with PDGFRA protein expression using immunohistochemistry (IHC). The expression of PDGFRA was also correlated with cytological atypia: PDGFRA was not overexpressed in intimal spreading cells that displayed the lowest degree of atypia while PDGFRA overexpression and amplification were observed in invasive cells of progressive areas such as the aortic wall and a pulmonary metastatic site, which showed increased cytological atypia. Although PDGFRA has not been well examined on IHC, IHC of PDGFRA could be useful to diagnose IS. However, the areas within the tumor from which specimens are derived are important given potential intratumoral heterogeneity.     

Increased lymphatic vascular density is seen before colorectal cancers reach stage II and growth factor FGF‐2 is downregulated in tumor tissue compared with normal mucosa

Lymphangiogenesis is an important event in progression of colorectal cancer (CRC), and the estimated lymphatic vascular density (LVD) probably indicates facilitated lymphatic tumor cell invasion and metastasis. However, at what time point during tumor progression this process is triggered, is unclear. The aim of this study was twofold. Firstly, to examine LVD in paired samples of CRC tissue and normal mucosa with specific emphasis on possible difference in LVD between tumors stages II and III, and secondly, the expression of the lymphangiogenic growth factor fibroblast growth factor‐2 (FGF‐2). Eighteen patients were studied. Immunostaining for podoplanin was performed to highlight lymphatic vessels. FGF‐2 mRNA expression was determined by quantitative real‐time RT‐PCR, whereas protein expression was quantitatively assessed by densitometric analysis of Western blot signal intensity. The immunoblots were further validated by FGF‐2 immunostaining of histological sections. LVD was significantly increased in tumor tissue compared with the normal mucosa but no changes in LVD between stages II and III CRC was observed. FGF‐2 was found to be downregulated both at the mRNA and protein level in tumor tissues compared with normal mucosa. Lymphangiogenesis was triggered early in tumor development. An increased LVD was established before the tumor reached stage II. FGF‐2 was downregulated in tumor tissue. The importance of this finding remains unclear.