Gut-derived Endotoxin-TLR4 Signaling Drives MYC-Ig Translocation to Promote Lymphoproliferation through c-JUN and STAT3 Activation.

Synergism between obesity and virus infection promotes the development of B-cell lymphoma. In this study, we tested whether obesity-associated endotoxin release induced activation-induced cytidine deaminase (AID). TLR4 activation in turn caused c-JUN-dependent and STAT3-dependent translocations of MYC loci to suppress transactivation of CD95/FAS. We used viral nucleocapside Core transgenic (Tg) mice fed alcohol Western diet to determine whether oncogenesis arising from obesity and chronic virus infection occurred through TLR4-c-JUN-STAT3 pathways. Our results showed B cell-specific, c-Jun and/or Stat3 disruption reduced the incidence of splenomegaly in these mice. AID-dependent t(8;14) translocation was observed between the Ig promoter and MYC loci. Comparison with human B cells showed MYC-immunoglobulin (Ig) translocations after virus infection with lipopolysaccharide stimulation. Accordingly, human patients with lymphoma with virus infections and obesity showed a 40% incidence of MYC-Ig translocations. Thus, obesity and virus infection promote AID-mediated translocation between the Ig promoter and MYC through the TLR4-c-JUN axis, resulting in lymphoproliferation. Taken together, preventative treatment targeting either c-JUN and/or STAT3 may be effective strategies to prevent tumor development. IMPLICATIONS: Obesity increases gut-derived endotoxin which induces Toll-like receptor-mediated MYC-Ig translocation via c-JUN-STAT3, leading to lymphoproliferation.

Antimicrobial laser-activated sealants for combating surgical site infections.

Surgical-site infections (SSIs) occur in 2-5% of patients undergoing surgery in the US alone, impacting 300 000-500 000 lives each year, and presenting up to 11 times greater risk of death compared to patients without SSIs. The most common cause of SSI is Staphylococcus aureus, and methicillin-resistant S. aureus (MRSA) is the most common pathogen in community hospitals. Current clinical devices used for approximating incisions and traumatic lacerations include sutures, adhesives, tapes, or staples with or without antimicrobial incorporation. However, current closure technologies may not provide adequate protection against infection, are susceptible to wound dehiscence, and can result in delayed biomechanical recoveries. Laser-activated tissue repair is a sutureless technique in which chromophore-loaded sealants convert laser light energy to heat in order to induce rapid tissue sealing. Here, we describe the generation and evaluation of laser-activated sealant (LASE) biomaterials, in which, indocyanine green (ICG), an FDA-approved dye, was embedded in a silk fibroin matrix and cast into films as wound sealants. Silk-ICG films were subjected to different near-infrared (NIR) laser powers to identify temperatures optimal for laser sealing of soft tissues. A mathematical model was developed in order to determine the photothermal conversion efficiency of LASEs following laser irradiation. NIR laser activation of silk-ICG LASEs increased the recovery of skin biomechanical strength compared to sutured skin in full-thickness incisional wounds in immunocompetent mice, and live animal imaging indicated persistence of silk-ICG LASEs over several days. LASEs loaded with the antibiotic vancomycin demonstrated higher efficacies for combating MRSA infections in a mouse model of surgical site infection compared to antibacterial sutures. Our results demonstrate that LASEs can be loaded with antimicrobial drugs and may serve as new multifunctional biomaterials for rapid tissue sealing, repair and surgical site protection following surgery.

Copper-Eluting Fibers for Enhanced Tissue Sealing and Repair.

Copper ions play an important role in several physiological processes, including angiogenesis, growth factor induction and extracellular matrix remodeling, that modulate wound healing and tissue repair. In this work, copper-loaded alginate fibers were generated and used as surgical sutures for repair of incisional wounds in live mice. Approximately 95% of initially loaded copper ions were released from the sutures within the first 24 h following an initial burst release. This localized delivery of copper at the incision site resulted in significantly higher recovery in tissue biomechanical strengths compared to conventional nylon and calcium alginate sutures at early times following surgery. Irradiation of copper alginate sutures with near-infrared light resulted in a robust photothermal response and led to efficacies similar to those seen with nonirradiated sutures. Histopathology and immunohistological analyses indicated significantly reduced epithelial gap and higher number of CD31+ cells, which is indicative of increased angiogenesis around the incision site. Delivery of copper ions did not result in toxicity under the conditions employed. Our findings demonstrate that delivery of ionic copper from sutures resulted in efficacious approximation and healing of incisional wounds, and copper-eluting fibers may have translational potential for accelerating repair in surgical and trauma wounds.

Light-Activated Tissue-Integrating Sutures as Surgical Nanodevices.

Sutures are typically the primary means of soft tissue repair in surgery and trauma. Despite their widespread use, sutures do not result in immediate sealing of approximated tissues, which can result in bacterial infection and leakage. Nonabsorbable sutures and staples can be traumatic to tissue, and the trauma can be exacerbated by their subsequent removal. Use of cyanoacrylate glues is limited because of their brittleness and toxicity. In this work, laser-activated tissue-integrating sutures (LATIS) are described as novel nanodevices for soft tissue approximation and repair. Incorporation of gold nanorods within fibers generated from collagen result in LATIS fibers which demonstrate robust photothermal responses following irradiation with near infrared laser light. Compared to conventional sutures, LATIS fibers result in greater biomechanical recovery of incised skin in a mouse model of skin closure after spine surgeries. Histopathology analyses show improved repair of the epidermal gap in skin, which indicate faster tissue recovery using LATIS. The studies indicate that LATIS-facilitated approximation of skin in live mice synergizes the benefits of conventional suturing and laser-activated tissue integration, resulting in new approaches for faster sealing, tissue repair, and healing.

An inhibitor screen identifies histone-modifying enzymes as mediators of polymer-mediated transgene expression from plasmid DNA.

Effective transgene expression in mammalian cells relies on successful delivery, cytoplasmic trafficking, and nuclear translocation of the delivered vector, but delivery is impeded by several formidable physicochemical barriers on the surface of and within the target cell. Although methods to overcome cellular exclusion and endosomal entrapment have been studied extensively, strategies to overcome inefficient nuclear entry and subsequent intranuclear barriers to effective transient gene expression have only been sparsely explored. In particular, the role of nuclear packaging of DNA with histone proteins, which governs endogenous gene expression, has not been extensively elucidated in the case of exogenously delivered plasmids. In this work, a parallel screen of small molecule inhibitors of chromatin-modifying enzymes resulted in the identification of class I/II HDACs, sirtuins, LSD1, HATs, and the methyltransferases EZH2 and MLL as targets whose inhibition led to the enhancement of transgene expression following polymer-mediated delivery of plasmid DNA. Quantitative PCR studies revealed that HDAC inhibition enhances the amount of plasmid DNA delivered to the nucleus in UMUC3 human bladder cancer cells. Native chromatin immunoprecipitation (N-ChIP)-qPCR experiments in CHO-K1 cells indicated that plasmids indeed interact with intracellular core Histone H3, and inhibitors of HDAC and LSD1 proteins are able to modulate this interaction. Pair-wise treatments of effective inhibitors led to synergistic enhancement of transgene expression to varying extents in both cell types. Our results demonstrate that the ability to modulate enzymes that play a role in epigenetic processes can enhance the efficacy of non-viral gene delivery, resulting in significant implications for gene therapy and industrial biotechnology.

Emerging applications of exosomes in cancer therapeutics and diagnostics.

Exosomes are nanoscale extracellular vesicles that are shed from different cells in the body. Exosomes encapsulate several biomolecules including lipids, proteins, and nucleic acids, and can therefore play a key role in cellular communication. These vesicles can be isolated from different body fluids and their small sizes make them attractive in various biomedical applications. Here, we review state-of-the art approaches in exosome isolation and purification, and describe their potential use in cancer vaccines, drug delivery, and diagnostics.

Chemomechanically engineered 3D organotypic platforms of bladder cancer dormancy and reactivation.

Tumors undergo periods of dormancy followed by reactivation leading to metastatic disease. Arrest in the G0/G1 phase of the cell cycle and resistance to chemotherapeutic drugs are key hallmarks of dormant tumor cells. Here, we describe a 3D platform of bladder cancer cell dormancy and reactivation facilitated by a novel aminoglycoside-derived hydrogel, Amikagel. These 3D dormant tumor microenvironments (3D-DTMs) were arrested in the G0/G1 phase and were highly resistant to anti-proliferative drugs. Inhibition of targets in the cellular protein production machinery led to induction of endoplasmic reticulum (ER) stress and complete ablation of 3D-DTMs. Nanoparticle-mediated calcium delivery significantly accelerated ER stress-mediated 3D-DTM death. Transfer of 3D-DTMs onto weaker and adhesive Amikagels resulted in selective reactivation of a sub-population of N-cadherin deficient cells from dormancy. Whole-transcriptome analyses further indicated key biochemical differences between dormant and proliferative cancer cells. Taken together, our results indicate that 3D bladder cancer microenvironments of dormancy and reactivation can facilitate fundamental advances and novel drug discovery in cancer.

Folate receptor-targeted aminoglycoside-derived polymers for transgene expression in cancer cells.

Targeted delivery of anticancer therapeutics can potentially overcome the limitations associated with current chemotherapeutic regimens. Folate receptors are overexpressed in several cancers, including ovarian, triple-negative breast and bladder cancers, making them attractive for targeted delivery of nucleic acid therapeutics to these tumors. This work describes the synthesis, characterization and evaluation of folic acid-conjugated, aminoglycoside-derived polymers for targeted delivery of transgenes to breast and bladder cancer cell lines. Transgene expression was significantly higher with FA-conjugated aminoglycoside-derived polymers than with Lipofectamine, and these polymers demonstrated minimal cytotoxicty. Competitive inhibition using free folic acid significantly reduced transgene expression efficacy of folate-targeted polymers, suggesting a role for folate receptor-mediated uptake. High efficacy FA-targeted polymers were employed to deliver a plasmid expressing the TRAIL protein, which induced death in cancer cells. These results indicate that FA-conjugated aminoglycoside-derived polymers are promising for targeted delivery of nucleic acids to cancer cells that overexpress folate receptors.