Measuring translational research impact requires reaching beyond current metrics

Translational impact assessment is key to selecting those biomedical research discoveries most likely to be converted into viable new products to improve human health. However, metrics for translational success are variable, are not limited to commercial success, and may not be relevant to every case or institution. Societal impact is a top translational priority in a globalized society.

Unusual subunits are directly involved in binding substrates for natural rubber biosynthesis in multiple plant species

Rubber particles from rubber-producing plant species have many different species-specific proteins bound to their external monolayer biomembranes. To date, identification of those proteins directly involved in enzymatic catalysis of rubber polymerization has not been fully accomplished using solubilization, purification or reconstitution approaches. In an alternative approach, we use several tritiated photoaffinity-labeled benzophenone analogs of the allylic pyrophosphate substrates, required by rubber transferase (RT-ase) to initiate the synthesis of new rubber molecules, to identify the proteins involved in catalysis. Enzymatically-active rubber particles were purified from three phylogenetically-distant rubber producing species, Parthenium argentatum Gray, Hevea brasiliensis Muell. Arg, and Ficus elastica Roxb., each representing a different Superorder of the Dicotyledonae. Geranyl pyrophosphate with the benzophenone in the para position (Bz-GPP(p)) was the most active initiator of rubber biosynthesis in all three species. When rubber particles were exposed to ultra-violet radiation, 95% of RT-ase activity was eliminated in the presence of 50 μΜ Bz-GPP(p), compared to only 50% of activity in the absence of this analog. ³H-Bz-GPP(p) then was used to label and identify the proteins involved in substrate binding and these proteins were characterized electrophoretically. In all three species, three distinct proteins were labeled, one very large protein and two very small proteins, as follows: P. argentatum 287,000, 3,990, and 1,790 Da; H. brasiliensis 241,000, 3,650 and 1,600 Da; F. elastica 360,000, 3,900 and 1,800 Da. The isoelectric points of the P. argentatum proteins were 7.6 for the 287,000 Da, 10.4 for the 3,990 Da and 3.5 for the 1,790 Da proteins, and of the F. elastica proteins were 7.7 for the 360,000 Da, 6,0 for the 3,900 Da, and 11.0 for the 1,800 Da proteins. H. brasiliensis protein pI values were not determined. Additional analysis indicated that the three proteins are components of a membrane-bound complex and that the ratio of each small protein to the large one is 3:1, and the large protein exists as a dimer. Also, the large proteins are membrane bound whereas both small proteins are strongly associated with the large proteins, rather than to the rubber particle proteolipid membrane.

A synthetic glycosaminoglycan reduces sinonasal inflammation in a murine model of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is characterized by sustained mucosal inflammation, impaired mucociliary clearance, loss of cilia and epithelial barrier breakdown, and tissue remodeling. Certain glycosaminoglycans inhibit various inflammatory mediators, suppress bacterial growth, and provide important functions in mucosal tissue repair and mucociliary clearance. Herein, we evaluated the effects of a synthetic glycosaminoglycan, GM-1111, on the clinical signs and inflammatory tissue changes associated with CRS in mice. CRS was generated by repeated intranasal applications of Aspergillus fumigatus (A. fumigatus) extracts over 4 weeks. Mice were then intranasally administered GM-1111 (600 μg per dose, 5 times a week) or vehicle (phosphate buffered saline, PBS) for an additional 4 weeks while still being given A. fumigatus extracts to maintain a chronic inflammatory environment with acute exacerbations. Clinical signs indicative of sinonasal inflammation were recorded throughout the study. After 9 weeks, whole blood and sinonasal tissues were harvested for hematological, histological, and biochemical examination. The clinical signs, white blood cell counts, tissue markers of sinonasal inflammation, and histological changes caused by A. fumigatus extract administration were compared to the healthy (PBS vehicle) and GM-1111-treated groups (n = 12 per treatment group). Compared to vehicle-treated animals, animals treated with GM-1111 demonstrated significant reductions in clinical signs (p<0.05), degenerative tissue changes, goblet cell hyperplasia, inflammatory cell infiltration (p<0.01), innate immunity- (tlr2, tlr4, myd88, il1b, tnfa, il6, and il12) and adaptive immunity-associated (ccl11, ccl24, ccl5, il4, il5, and il13) cytokine gene expression (p<0.05 to p<0.0001) in sinonasal tissues, and serum IgE levels (p<0.01). Our data suggest that GM-1111 significantly reduces local and systemic effects of CRS-associated sinonasal inflammation.

Composition of Hyaluronan Affects Wound Healing in the Rabbit Maxillary Sinus

Background

Hyaluronan (HA) is a ubiquitous component of the extracellular matrix. HA and its derivatives have been used in the sinuses to reduce scarring and possibly promote wound healing. However, in recent animal studies, HA esters exhibited inflammatory effects. Mitomycin C (MMC) is another potential antiscarring treatment. This study prospectively evaluated the effects of three different HA constructs on wound healing in the rabbit maxillary sinus: (i) a novel cross-linked HA hydrogel, (ii) the cross-linked HA gel containing covalently bound MMC, and (iii) a commercially available woven HA ester (Merogel).

Methods

Ostia were created with a 4-mm otologic drill in the maxillary sinuses of 15 New Zealand white rabbits with one side randomly chosen for treatment. After 14 or 21 days the size of the maxillary ostia were recorded and the tissue was examined under light microscopy.

Results

Sinuses treated with the novel HA and HA-MMC hydrogels showed an increased ostial diameter compared with untreated controls. Woven HA ester–treated sinuses showed no improvement, with a trend toward a smaller ostium than controls. Histological examination showed that woven HA ester tended to cause increased fibrosis and granulomatous inflammation, and heterophilia was slightly increased in the HA hydrogel-treated sinuses. Blinded observation noted foamy macrophages surrounding the residual woven HA ester in each specimen while no similar reaction was noted near the residual HA or HA-MMC hydrogels.

Conclusion

This study suggests that the degree of ostial narrowing, inflammation, and fibrosis depends on the formulation of the HA used. Minimal, if any, additional benefit is seen with addition of MMC to the HA hydrogel in this pilot study.

Bladder pain in an LL-37 interstitial cystitis and painful bladder syndrome model

Our goal was to evaluate the pain response in an LL-37 induced murine model for interstitial cystitis/painful bladder syndrome (IC/PBS). In particular, we sought to characterize the dose dependence, time-course, and relationship of LL-37 induced bladder inflammation and pain. The IC/PBS model was induced in C57Bl/6 mice by instilling 50 μL of LL-37, an immunomodulatory human cathelicidin (anti-microbial peptide), in the bladder for 1 hr. Pain responses were measured using von Frey filaments (0.04 gm to 4.0 gm) before and after LL-37 instillation. Inflammation was evaluated using tissue myeloperoxidase (MPO) assay, gross inspection, and microscopic histologic examination. The dose response experiment demonstrated a graded pain response, with higher concentrations of LL-37 challenge yielding higher pain responses across all stimuli tested. Statistical significance was seen when comparing 1.0 gm von Frey filament results at 320 μM (68 ± 8% response) vs. 0 μM (38 ± 6% response). Interestingly, pain responses did not attenuate across time but increased significantly after 5 (p=0.0012) and 7 days (p=0.0096). Comparison with MPO data suggested that pain responses could be independent of inflammation. We demonstrated within our LL-37 induced IC/PBS model pain occurs in a dose-dependent fashion, pain responses persist beyond the initial point of insult, and our dose response and time course experiments demonstrated that pain was independent of inflammation.

Silk-elastinlike protein polymers enhance the efficacy of a therapeutic glycosaminoglycan for prophylactic treatment of radiation-induced proctitis

Radiation-induced proctitis (RIP) is the most common clinical adverse effect for patients receiving radiotherapy as part of the standard course of treatment for ovarian, prostate, colon, and bladder cancers. RIP limits radiation dosage, interrupts treatment, and lowers patients' quality of life. A prophylactic treatment that protects the gastrointestinal tract from deleterious effects of radiotherapy will significantly improve patient quality of life and may allow for higher and more regular doses of radiation therapy. Semi-synthetic glycosaminoglycan (GAG), generated from the sulfation of hyaluronic acid, are anti-inflammatory but have difficulty achieving therapeutic levels in many tissues. To enhance the delivery of GAG, we created an in situ gelling rectal delivery system using silk-elastinlike protein polymers (SELPs). Using solutions of SELP 815K (which contains 6 repeats of blocks comprised of 8 silk-like units, 15 elastin-like units, and 1 lysine-substituted elastin-like unit) with GAG GM-0111, we created an injectable delivery platform that transitioned in <5min from a liquid at room temperature to a hydrogel at body temperature. The hydrogels released 50% of their payload within 30min and enhanced the accumulation of GAG in the rectum compared to traditional enema-based delivery. Using a murine model of radiation-induced proctitis, the prophylactic delivery of a single dose of GAG from a SELP matrix administered prior to irradiation significantly reduced radiation-induced pain after 3, 7, and 21days by 53±4%, 47±10%, and 12±6%, respectively. Matrix-mediated delivery of GAG by SELP represents an innovative method for more effective treatment of RIP and promises to improve quality of life of cancer patients by allowing higher radiotherapy doses with improved safety.

The Life of Pi Star: Exploring the Exciting and Forbidden Worlds of the Benzophenone Photophore

The widespread applications of benzophenone (BP) photochemistry in biological chemistry, bioorganic chemistry, and material science have been prominent in both academic and industrial research. BP photophores have unique photochemical properties: upon n-π* excitation at 365 nm, a biradicaloid triplet state is formed reversibly, which can abstract a hydrogen atom from accessible C-H bonds; the radicals subsequently recombine, creating a stable covalent C-C bond. This light-directed covalent attachment process is exploited in many different ways: (i) binding/contact site mapping of ligand (or protein)-protein interactions; (ii) identification of molecular targets and interactome mapping; (iii) proteome profiling; (iv) bioconjugation and site-directed modification of biopolymers; (v) surface grafting and immobilization. BP photochemistry also has many practical advantages, including low reactivity toward water, stability in ambient light, and the convenient excitation at 365 nm. In addition, several BP-containing building blocks and reagents are commercially available. In this review, we explore the "forbidden" (transitions) and excitation-activated world of photoinduced covalent attachment of BP photophores by touring a colorful palette of recent examples. In this exploration, we will see the pros and cons of using BP photophores, and we hope that both novice and expert photolabelers will enjoy and be inspired by the breadth and depth of possibilities.

Prevention of sinonasal inflammation by a synthetic glycosaminoglycan

BACKGROUND

Glycosaminoglycans (GAGs) are polysaccharides that are distributed on respiratory epithelial cells, endothelial cells, and submucosal glands. Uniquely positioned, certain GAGs exhibit anti-inflammatory properties in respiratory diseases and serve important roles in repairing mucosal surfaces and modulating mucociliary clearance. We hypothesized that topical administration of a synthetic GAG (GM-0111) would prevent sinonasal inflammation in a mouse model of rhinosinusitis (RS).

METHODS

To test our hypothesis, C57BL/6 mice were intranasally administered fluorescent GM-0111, and sinonasal tissues were examined for coating and penetration ability. To test therapeutic feasibility, mice (n = 6) were given GM-0111 or hyaluronic acid (HA; 800 μg dose) prior to inducing RS with inflammatory molecule LL-37 (115 μg dose). After 24 hours, sinonasal tissues were harvested for histological and biochemical analysis of inflammatory markers (inflammatory cell infiltration, lamina propria [LP] thickening, and neutrophil enzyme myeloperoxidase [MPO]) and cell death.

RESULTS

GM-0111 was observed within sinonasal tissues 1 hour and 24 hours after intranasal administration, indicating rapid and effective coating and penetration. GM-0111 prevented sinonasal tissues from developing inflammatory changes, with significant reductions in mast cell infiltration (p < 0.05), LP thickening (p < 0.001), and MPO levels (p < 0.01) when compared to tissues treated with LL-37 and those pretreated with HA. GM-0111 reduced cell death within sinonasal tissues in contrast to LL-37-treated tissues.

CONCLUSION

We report a new synthetic GAG (GM-0111) that uniformly coats and penetrates into the sinonasal mucosa to prevent sinonasal inflammation and cell death in a mouse model of RS.

TRPV4 regulates calcium homeostasis, cytoskeletal remodeling, conventional outflow and intraocular pressure in the mammalian eye

An intractable challenge in glaucoma treatment has been to identify druggable targets within the conventional aqueous humor outflow pathway, which is thought to be regulated/dysregulated by elusive mechanosensitive protein(s). Here, biochemical and functional analyses localized the putative mechanosensitive cation channel TRPV4 to the plasma membrane of primary and immortalized human TM (hTM) cells, and to human and mouse TM tissue. Selective TRPV4 agonists and substrate stretch evoked TRPV4-dependent cation/Ca²⁺ influx, thickening of F-actin stress fibers and reinforcement of focal adhesion contacts. TRPV4 inhibition enhanced the outflow facility and lowered perfusate pressure in biomimetic TM scaffolds populated with primary hTM cells. Systemic delivery, intraocular injection or topical application of putative TRPV4 antagonist prodrug analogs lowered IOP in glaucomatous mouse eyes and protected retinal neurons from IOP-induced death. Together, these findings indicate that TRPV4 channels function as a critical component of mechanosensitive, Ca²⁺-signaling machinery within the TM, and that TRPV4-dependent cytoskeletal remodeling regulates TM stiffness and outflow. Thus, TRPV4 is a potential IOP sensor within the conventional outflow pathway and a novel target for treating ocular hypertension.

In Vivo Engineering of the Vocal Fold Extracellular Matrix with Injectable Hyaluronic Acid Hydrogels: Early Effects on Tissue Repair and Biomechanics in a Rabbit Model

Objectives:

A prospective, controlled animal study was performed to determine whether the use of injectable, chemically modified hyaluronic acid (HA) derivatives at the time of intentional vocal fold resection might facilitate wound repair and preserve the unique viscoelastic properties of the vocal fold extracellular matrix.

Methods:

We performed bilateral vocal fold biopsies on 33 rabbits. Two groups of rabbits were unilaterally treated with 2 different HA derivatives — Carbylan-SX and HA-DTPH-PEGDA — at the time of resection. Saline was injected as a control into the contralateral fold. The animals were painlessly sacrificed 3 weeks after biopsy and injection. The outcomes measured included histologic fibrosis level, tissue HA level, and tissue viscosity and elasticity.

Results:

The Carbylan-SX—treated vocal folds were found to have significantly less fibrosis than the saline-treated controls. The levels of HA in the treated vocal folds were not significantly different from those in the controls at 3 weeks as measured by enzyme-linked immunosorbent assay. The Carbylan-SX—treated vocal folds had significantly improved biomechanical properties of elasticity and viscosity. The HA-DTPH-PEGDA injections yielded significantly improved viscosity, but not elasticity.

Conclusions:

Prophylactic in vivo manipulation of the extracellular matrix with an injectable Carbylan-SX hydrogel appears to induce vocal fold tissue regeneration to yield optimal tissue composition and biomechanical properties favorable for phonation.

A Modified Glycosaminoglycan, GM-0111, Inhibits Molecular Signaling Involved in Periodontitis

Background

Periodontitis is characterized by microbial infection, inflammation, tissue breakdown, and accelerated loss of alveolar bone matrix. Treatment targeting these multiple stages of the disease provides ways to treat or prevent periodontitis. Certain glycosaminoglycans (GAGs) block multiple inflammatory mediators as well as suppress bacterial growth, suggesting that these GAGs may be exploited as a therapeutic for periodontitis.

Methods

We investigated the effects of a synthetic GAG, GM-0111, on various molecular events associated with periodontitis: growth of Porphyromonas gingivalis (P. gingivalis) and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans) pathogenic bacteria associated with periodontitis; activation of pro-inflammatory signaling through TLR2 and TLR4 in mouse macrophage RAW 264.7 cells and heterologously expressed HEK 293 cells; osteoclast formation and bone matrix resorption in cultured mouse pre-osteoclasts.

Results

(1) GM-0111 suppressed the growth of P. gingivalis and A. actinomycetemcomitans even at 1% (w/v) solution. The antibacterial effects of GM-0111 were stronger than hyaluronic acid (HA) or xylitol in P. gingivalis at all concentrations and comparable to xylitol in A. actinomycetemcomitans at ≥2% (w/v) solution. We also observed that GM-0111 suppressed biofilm formation of P. gingivalis and these effects were much stronger than HA. (2) GM-0111 inhibited TLR-mediated pro-inflammatory cellular signaling both in macrophage and HEK 293 cells with higher selectivity for TLR2 than TLR4 (IC₅₀ of 1–10 ng/mL vs. > 100 μg/mL, respectively). (3) GM-0111 blocked RANKL-induced osteoclast formation (as low as 300 ng/mL) and bone matrix resorption. While GM-0111 showed high affinity binding to RANKL, it did not interfere with RANKL/RANK/NF-κB signaling, suggesting that GM-0111 inhibits osteoclast formation by a RANKL-RANK-independent mechanism.

Conclusions

We report that GM-0111 inhibits multiple molecular events involved in periodontitis, spanning from the early pro-inflammatory TLR signaling, to pathways activated at the later stage component of bone loss.

Crosslinked hydrogels for tympanic membrane repair

PROBLEM: To provide a less expensive and more convenient protocol for the treatment of tympanic membrane perforations (TMPs).

METHODS: Several materials were prepared and compared for TMP repair including Carbylan-SX, Gelatin-DTPH-PEGDA (GX), Carbylan-S/Gelatin-DTPH (Carbylan-GSX) (injectable and sponge), Gelfoam, Epifilm, and crosslinked thiolated chondroitin sulfate (CS-DTPH-PEGDA [CS-SX]). Hartley pigmented guinea pigs (Elm Hill) underwent bilateral myringotomy with 1 ear left as a control and the other treated with one of the previously mentioned materials.

RESULTS: Carbylan-GSX (injectable and sponge), Gelfoam with saline, and CS-SX had the shortest time for TMP closure. Epifilm, Carbylan, and gelatin preparations resulted in closure rates similar to controls. CS-SX showed a marked inflammatory reaction compared with controls and other materials based on neutrophil, lymphocyte, epitheloid counts, and degree of fibrosis.

CONCLUSIONS: This study shows the validity of Carbylan-GSX compared with Gelfoam as a material to promote TMP closure in an acute TMP guinea pig model.

Recent advances in hyaluronic acid hydrogels for biomedical applications

Hyaluronic acid (HA) is widely used in the design of engineered hydrogels, due to its biofunctionality, as well as numerous sites for modification with reactive groups. There are now widespread examples of modified HA macromers that form either covalent or physical hydrogels through crosslinking reactions such as with click chemistry or supramolecular assemblies of guest-host pairs. HA hydrogels range from relatively static matrices to those that exhibit spatiotemporally dynamic properties through external triggers like light. Such hydrogels are being explored for the culture of cells in vitro, as carriers for cells in vivo, or to deliver therapeutics, including in an environmentally responsive manner. The future will bring new examples of HA hydrogels due to the synthetic diversity of HA.

Dual Action of Lysophosphatidate-Functionalised Titanium: Interactions with Human (MG63) Osteoblasts and Methicillin Resistant Staphylococcus aureus

Titanium (Ti) is a widely used material for surgical implants; total joint replacements (TJRs), screws and plates for fixing bones and dental implants are forged from Ti. Whilst Ti integrates well into host tissue approximately 10% of TJRs will fail in the lifetime of the patient through a process known as aseptic loosening. These failures necessitate revision arthroplasties which are more complicated and costly than the initial procedure. Finding ways of enhancing early (osseo)integration of TJRs is therefore highly desirable and continues to represent a research priority in current biomaterial design. One way of realising improvements in implant quality is to coat the Ti surface with small biological agents known to support human osteoblast formation and maturation at Ti surfaces. Lysophosphatidic acid (LPA) and certain LPA analogues offer potential solutions as Ti coatings in reducing aseptic loosening. Herein we present evidence for the successful bio-functionalisation of Ti using LPA. This modified Ti surface heightened the maturation of human osteoblasts, as supported by increased expression of alkaline phosphatase. These functionalised surfaces also deterred the attachment and growth of Staphylococcus aureus, a bacterium often associated with implant failures through sepsis. Collectively we provide evidence for the fabrication of a dual-action Ti surface finish, a highly desirable feature towards the development of next-generation implantable devices.

Topical cathelicidin (LL-37) an innate immune peptide induces acute olfactory epithelium inflammation in a mouse model

BACKGROUND

Cathelicidin (LL-37) is an endogenous innate immune peptide that is elevated in patients with chronic rhinosinusitis (CRS). The role of LL-37 in olfactory epithelium (OE) inflammation remains unknown. We hypothesized that: (1) LL-37 topically delivered would elicit profound OE inflammation; and (2) LL-37 induced inflammation is associated with increased infiltration of neutrophils and mast cells.

METHODS

To test our hypothesis we challenged C57BL/6 mice intranasally with increasing concentrations of LL-37. At 24 hours tissues were examined histologically and scored for inflammatory cell infiltrate, edema, and secretory hyperplasia. In separate experiments, fluorescently conjugated LL-37 was instilled and tissues were examined at 0.5 and 24 hours. To test our last hypothesis, we performed tissue myeloperoxidase (MPO) assays for neutrophil activity and immunohistochemistry for tryptase to determine the mean number of mast cells per mm(2) .

RESULTS

LL-37 caused increased inflammatory cell infiltrate, edema, and secretory cell hyperplasia of the sinonasal mucosa, with higher LL-37 concentrations yielding significantly more inflammatory changes (p < 0.01). Fluorescent LL-37 demonstrated global sinonasal epithelial binding and tissue distribution. Further, higher concentrations of LL-37 led to significantly greater MPO levels with dose-dependent increases in mast cell infiltration (p < 0.01).

CONCLUSION

LL-37 has dramatic inflammatory effects in the OE mucosa that is dose-dependent. The observed inflammatory changes in the olfactory mucosa were associated with the infiltration of both neutrophils and mast cells. Our biologic model represents a new model to further investigate the role of LL-37 in OE inflammation.

Autotaxin and Endotoxin-Induced Acute Lung Injury

Acute Lung Injury (ALI) is a life-threatening, diffuse heterogeneous lung injury characterized by acute onset, pulmonary edema and respiratory failure. Lipopolysaccharide (LPS) is a common cause of both direct and indirect lung injury and when administered to a mouse induces a lung phenotype exhibiting some of the clinical characteristics of human ALI. Here, we report that LPS inhalation in mice results in increased bronchoalveolar lavage fluid (BALF) levels of Autotaxin (ATX, Enpp2), a lysophospholipase D largely responsible for the conversion of lysophosphatidylcholine (LPC) to lysophosphatidic acid (LPA) in biological fluids and chronically inflamed sites. In agreement, gradual increases were also detected in BALF LPA levels, following inflammation and pulmonary edema. However, genetic or pharmacologic targeting of ATX had minor effects in ALI severity, suggesting no major involvement of the ATX/LPA axis in acute inflammation. Moreover, systemic, chronic exposure to increased ATX/LPA levels was shown to predispose to and/or to promote acute inflammation and ALI unlike chronic inflammatory pathophysiological situations, further suggesting a differential involvement of the ATX/LPA axis in acute versus chronic pulmonary inflammation.

Vinyl sulfone analogs of lysophosphatidylcholine irreversibly inhibit autotaxin and prevent angiogenesis in melanoma

Autotaxin (ATX) is an enzyme discovered in the conditioned medium of cultured melanoma cells and identified as a protein that strongly stimulates motility. This unique ectonucleotide pyrophosphatase and phosphodiesterase facilitates the removal of a choline headgroup from lysophosphatidylcholine (LPC) to yield lysophosphatidic acid (LPA), which is a potent lipid stimulator of tumorigenesis. Thus, ATX has received renewed attention because it has a prominent role in malignant progression with significant translational potential. Specifically, we sought to develop active site-targeted irreversible inhibitors as anti-cancer agents. Herein we describe the synthesis and biological activity of an LPC-mimetic electrophilic affinity label that targets the active site of ATX, which has a critical threonine residue that acts as a nucleophile in the lysophospholipase D reaction to liberate choline. We synthesized a set of quaternary ammonium derivative-containing vinyl sulfone analogs of LPC that function as irreversible inhibitors of ATX and inactivate the enzyme. The analogs were tested in cell viability assays using multiple cancer cell lines. The IC50 values ranged from 6.74 to 0.39 μM, consistent with a Ki of 3.50 μM for inhibition of ATX by the C16H33 vinyl sulfone analog CVS-16 (10b). A phenyl vinyl sulfone control compound, PVS-16, lacking the choline-like quaternary ammonium mimicking head group moiety, had little effect on cell viability and did not inhibit ATX. Most importantly, CVS-16 (10b) significantly inhibited melanoma progression in an in vivo tumor model by preventing angiogenesis. Taken together, this suggests that CVS-16 (10b) is a potent and irreversible ATX inhibitor with significant biological activity both in vitro and in vivo.

Ophthalmic Uses of a Thiol-Modified Hyaluronan-Based Hydrogel

Significance: Hyaluronic acid (HA, or hyaluronan) is a ubiquitous naturally occurring polysaccharide that plays a role in virtually all tissues in vertebrate organisms. HA-based hydrogels have wound-healing properties, support cell delivery, and can deliver drugs locally. Recent Advances: A few HA hydrogels can be customized for composition, physical form, and biomechanical properties. No clinically approved HA hydrogel allows for in vivo crosslinking on administration, has a tunable gelation time to meet wound-healing needs, or enables drug delivery. Recently, a thiolated carboxymethyl HA (CMHA-S) was developed to produce crosslinked hydrogels, sponges, and thin films. CMHA-S can be crosslinked with a thiol-reactive crosslinker or by oxidative disulfide bond formation to form hydrogels. By controlled crosslinking, the shape and form of this material can be manipulated. These hydrogels can be subsequently lyophilized to form sponges or air-dried to form thin films. CMHA-S films, liquids, and gels have been shown to be effective in vivo for treating various injuries and wounds in the eye in veterinary use, and are in clinical development for human use. Critical Issues: Better clinical therapies are needed to treat ophthalmic injuries. Corneal wounds can be treated using this HA-based crosslinked hydrogel. CMHA-S biomaterials can help heal ocular surface defects, can be formed into a film to deliver drugs for local ocular drug delivery, and could deliver autologous limbal stem cells to treat extreme ocular surface damage associated with limbal stem cell deficiencies. Future Directions: This CMHA-S hydrogel increases the options that could be available for improved ocular wound care, healing, and regenerative medicine.

Abstract 3965: Modulating glutathione s-transferase M4 activity for the treatment of Ewing sarcoma

Ewing sarcoma is a malignant pediatric bone and soft tissue tumor. The prognosis for Ewing sarcoma remains dismal despite of intensive treatments including surgery, radiation, and chemotherapy. Moreover, these unspecific treatments often have severe side effects. We previously reported that Glutathione S-transferase M4 (GSTM4) is a potential specific treatment target for Ewing sarcoma. GSTM4 is required for oncogenic transformation and confers chemotherapeutic drug resistance in Ewing sarcoma cells; high GSTM4 level in primary tumor is correlated with poor patient outcome. Here we further evaluate the efficacy of modulating GSTM4 activity in treating Ewing sarcoma using patient-derived cells and mouse xenograft models. RNA-seq analysis for RNA levels of all GSTs in A673 Ewing sarcoma cells as well as online database searching for GSTM4 RNA level in tumor samples of various sarcomas demonstrate that GSTM4 is specifically highly expressed in Ewing sarcoma. By MTT and soft agar assays, we find that NBDHEX, a GSTM4 inhibitory compound, inhibits cellular proliferation and oncogenic transformation of Ewing sarcoma cells. Furthermore, NBDHEX has a synergistic effect in cytotoxicity with chemotherapeutic drug etoposide. Conversely, a GSTM4-activated anti-cancer agent, JS-K, significantly decreases Ewing sarcoma cell viability (p&lt;0.05). We find that JS-K works through GSTM4 because knockdown of GSTM4 by shRNA in Ewing sarcoma cells significantly decreases their sensitivity to JS-K (p&lt;0.05). Moreover, JS-K significantly decreases Ewing sarcoma xenograft tumor growth in immunodeficient mice (Mantel-Cox test p=0.0002). Next we examine the underlying mechanism of GSTM4 mediated drug resistance and find that GSTM4 interacts with Apoptosis Signal-regulating Kinase 1 (ASK1) and inhibits ASK1 activation of c-Jun N-terminal Kinase (JNK) mediated apoptosis upon etoposide treatment. Taken together, these data provide further evidence that GSTM4 is a novel therapeutic target for Ewing sarcoma. GSTM4 targeted inhibition by inhibitors or knockdown by RNA interference combined with standard chemotherapeutic regimens are potential treatments more specific and effective for Ewing sarcoma. GSTM4 pro-drugs are promising for treatment of patients with high GSTM4 expression tumors. Our data also suggest that agents intervening of GSTM4/ASK interaction may increase drug sensitivity of Ewing sarcoma cells and tumors and therefore be of therapeutic values.

Citation Format: Rupeng Zhuo, Kenneth M. Kosak, Savita Sankar, Elizabeth T. Wiles, Yin Sun, Jianxing Zhang, Glenn D. Prestwich, Paul J. Shami, Stephen L. Lessnick, Mitchell S. Cairo, Wen Luo. Modulating glutathione s-transferase M4 activity for the treatment of Ewing sarcoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3965. doi:10.1158/1538-7445.AM2014-3965

Abstract 2672: Vinyl sulfone analogues of lysophosphatidylcholine irreversibly inhibit autotaxin and prevent angiogenesis in melanoma

Autotaxin (ATX) is an enzyme discovered in the conditioned medium of cultured melanoma cells and identified as a protein that strongly stimulates motility. This unique ectonucleotide pyrophosphatase and phosphodiesterase facilitates the removal of a choline headgroup from lysophosphatidylcholine (LPC) to yield lysophosphatidic acid (LPA), which is a potent lipid stimulator of tumorigenesis. Thus, ATX has received renewed attention because it has a prominent role in malignant progression and represents a promising area of research with significant translational potential. Since ATX inhibitors may have broad implications for therapy, we sought to create a novel series of inhibitors for use against cancer, especially melanoma. Herein we report on the synthesis and biological activity of a targeted affinity label for the active site of ATX, which has a critical threonine residue that acts as a nucleophile in the lysophospholipase D reaction to liberate choline. We synthesized a set of vinyl sulfone analogs of ATX that function as irreversible inhibitors of ATX and inactivate the enzyme. We commenced biological testing of this compound with viability assays against multiple cancer cell lines whereby the IC50 values ranged from 6.74 - 0.39 μM, which was consistent with the Ki of the vinyl sulfone (3.50 μM). In addition, this compound was also able to significantly inhibit melanoma cell wound closure and pore migration. Most importantly, the vinyl sulfone significantly inhibited melanoma progression using an in vivo tumor model by preventing angiogenesis. Taken together, this suggests that the vinyl sulfone is a potent and irreversible ATX inhibitor with significant biological activity both in vitro and in vivo.

Note: This abstract was not presented at the meeting.

Citation Format: Mandi M. Murph, Molly Altman, Wei Jia, Duy Nguyen, Jada Fambrough, William J. Hardman, Guowei Jiang, Damian Madan, Jianxing Zhang, Glenn D. Prestwich. Vinyl sulfone analogues of lysophosphatidylcholine irreversibly inhibit autotaxin and prevent angiogenesis in melanoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2672. doi:10.1158/1538-7445.AM2014-2672

Targeting Glutathione S-transferase M4 in Ewing sarcoma

Ewing sarcoma is a malignant pediatric bone and soft tissue tumor. Although the 5-year survival rate of localized disease approaches 75%, the prognosis of metastatic and/or therapy-resistant disease remains dismal despite the wide use of aggressive therapeutic strategies. We previously reported that high expression of glutathione S-transferase M4 (GSTM4) in primary tumors correlates with poor patient outcomes. GSTM4 is required for oncogenic transformation and mediates resistance to chemotherapeutic drugs in Ewing sarcoma cells. Here, we performed RNA-sequencing analyses of Ewing sarcoma cells and combined our results with publicly available datasets to demonstrate that GSTM4 is a major GST specifically expressed in Ewing sarcoma. Pharmacological inhibition of GSTM4 activity using a pan GST inhibitor, 6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio) hexanol (NBDHEX), significantly limited cellular proliferation and oncogenic transformation of Ewing sarcoma cells. Moreover, combined use of NBDHEX and etoposide synergistically increased cytotoxicity, suggesting a role for GSTM4 as an inhibitor of apoptosis. Mechanistic studies revealed that GSTM4 limits apoptosis owing to its ability to interact with Apoptosis Signal-regulating Kinase 1 (ASK1) and inhibit signaling via the c-Jun N-terminal Kinase axis. To exploit our observation that GSTM4 expression is specifically up-regulated in Ewing sarcoma, we tested the effect of a GSTM4-activated anti-cancer agent, O(2)-(2,4-dinitrophenyl) 1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate or JS-K, on tumor growth and survival. We found that JS-K robustly decreased Ewing sarcoma cell viability and xenograft tumor growth and improved overall survival of xenograft mice. Our data suggest that GSTM4 is a novel therapeutic target for the treatment of high GSTM4-expressing Ewing sarcoma. Strategies that combine standard chemotherapy with agents that inhibit GSTM4, that are activated by GSTM4, or that block GSTM4/ASK1 interactions, can potentially be more specific and/or efficacious than standard therapeutic approaches.

Augmentation of integrin-mediated mechanotransduction by hyaluronic acid

Changes in tissue and organ stiffness occur during development and are frequently symptoms of disease. Many cell types respond to the stiffness of substrates and neighboring cells in vitro and most cell types increase adherent area on stiffer substrates that are coated with ligands for integrins or cadherins. In vivo cells engage their extracellular matrix (ECM) by multiple mechanosensitive adhesion complexes and other surface receptors that potentially modify the mechanical signals transduced at the cell/ECM interface. Here we show that hyaluronic acid (also called hyaluronan or HA), a soft polymeric glycosaminoglycan matrix component prominent in embryonic tissue and upregulated during multiple pathologic states, augments or overrides mechanical signaling by some classes of integrins to produce a cellular phenotype otherwise observed only on very rigid substrates. The spread morphology of cells on soft HA-fibronectin coated substrates, characterized by formation of large actin bundles resembling stress fibers and large focal adhesions resembles that of cells on rigid substrates, but is activated by different signals and does not require or cause activation of the transcriptional regulator YAP. The fact that HA production is tightly regulated during development and injury and frequently upregulated in cancers characterized by uncontrolled growth and cell movement suggests that the interaction of signaling between HA receptors and specific integrins might be an important element in mechanical control of development and homeostasis.

Interspecific variation of diterpene composition ofCubitermes soldier defense secretions

Soldiers of the humivorous termite generaCubitermes andCrenetermes (Isoptera: Termitidae: Termitinae) secrete a mixture of unusual diterpene hydrocarbons from the fontanellar opening of the frontal gland. The defense secretions of sixCubitermes species and oneCrenetermes species show species-specific distributions of the five chemically identified major components and 12 unidentified minor components. The secretion is also present with its characteric terpene distribution in white presoldiers and newly molted soldiers, but is completely absent in workers.

Autotaxin production of lysophosphatidic acid mediates allergic asthmatic inflammation

RATIONALE

Bioactive lipid mediators, derived from membrane lipid precursors, are released into the airway and airspace where they bind high-affinity cognate receptors and may mediate asthma pathogenesis. Lysophosphatidic acid (LPA), a bioactive lipid mediator generated by the enzymatic activity of extracellular autotaxin (ATX), binds LPA receptors, resulting in an array of biological actions on cell proliferation, migration, survival, differentiation, and motility, and therefore could mediate asthma pathogenesis.

OBJECTIVES

To define a role for the ATX-LPA pathway in human asthma pathogenesis and a murine model of allergic lung inflammation.

METHODS

We investigated the profiles of LPA molecular species and the level of ATX exoenzyme in bronchoalveolar lavage fluids of human patients with asthma subjected to subsegmental bronchoprovocation with allergen. We interrogated the role of the ATX-LPA pathway in allergic lung inflammation using a murine allergic asthma model in ATX-LPA pathway-specific genetically modified mice.

MEASUREMENTS AND MAIN RESULTS

Subsegmental bronchoprovocation with allergen in patients with mild asthma resulted in a remarkable increase in bronchoalveolar lavage fluid levels of LPA enriched in polyunsaturated 22:5 and 22:6 fatty acids in association with increased concentrations of ATX protein. Using a triple-allergen mouse asthma model, we showed that ATX-overexpressing transgenic mice had a more severe asthmatic phenotype, whereas blocking ATX activity and knockdown of the LPA2 receptor in mice produced a marked attenuation of Th2 cytokines and allergic lung inflammation.

CONCLUSIONS

The ATX-LPA pathway plays a critical role in the pathogenesis of asthma. These preclinical data indicate that targeting the ATX-LPA pathway could be an effective antiasthma treatment strategy.

Behavioral and neurosensory responses of the boll weevil,Anthonomus grandis Boh. (Coleoptera: Curculionidae), to fluorinated analogs of aldehyde components of its pheromone

Competitive field tests with α-fluorinated analogs of compounds III and IV (III-α-F and IV-α-F, respectively) of the boll weevil,Anthonomus grandis Boh., aggregation pheromone showed these compounds, when combined with the other pheromone components [(±)-I and II], to be as attractive as grandlure [(+)-I, II, and III+IV]. Dose-response curves constructed from electroantennograms of male boll weevils to serial stimulus loads of III, IV, III-α-F, IV-α-F, and the corresponding acyl fluorinated analogs (III-acyl-F and IV-acyl-F) showed the α-fiuorinated analogs to be as active as the pheromone components (threshold=0.1 μg), while the acyl fluorinated analogs had a 10-100 x higher threshold (=1-10 μg). Single-neuron recordings showed that IV neurons and II neurons (Dickens, 1990) responded to IV-α-F and III-α-F, respectively, while IV-acyl-F and III-acyl-F were inactive. Since a previous study showed compounds I, II, and IV to be essential for behavioral responses in the field, it seems likely that the activity of the α-fluorinated analogs observed here is due to the stimulation of IV neurons by IV-α-F as indicated in single neuron recordings.

Non-invasive imaging of tumors by monitoring autotaxin activity using an enzyme-activated near-infrared fluorogenic substrate

Autotaxin (ATX), an autocrine motility factor that is highly upregulated in metastatic cancer, is a lysophospholipase D enzyme that produces the lipid second messenger lysophosphatidic acid (LPA) from lysophosphatidylcholine (LPC). Dysregulation of the lysolipid signaling pathway is central to the pathophysiology of numerous cancers, idiopathic pulmonary fibrosis, rheumatoid arthritis, and other inflammatory diseases. Consequently, the ATX/LPA pathway has emerged as an important source of biomarkers and therapeutic targets. Herein we describe development and validation of a fluorogenic analog of LPC (AR-2) that enables visualization of ATX activity in vivo. AR-2 exhibits minimal fluorescence until it is activated by ATX, which substantially increases fluorescence in the near-infrared (NIR) region, the optimal spectral window for in vivo imaging. In mice with orthotopic ATX-expressing breast cancer tumors, ATX activated AR-2 fluorescence. Administration of AR-2 to tumor-bearing mice showed high fluorescence in the tumor and low fluorescence in most healthy tissues with tumor fluorescence correlated with ATX levels. Pretreatment of mice with an ATX inhibitor selectively decreased fluorescence in the tumor. Together these data suggest that fluorescence directly correlates with ATX activity and its tissue expression. The data show that AR-2 is a non-invasive and selective tool that enables visualization and quantitation of ATX-expressing tumors and monitoring ATX activity in vivo.

Prevention of anti-microbial peptide LL-37-induced apoptosis and ATP release in the urinary bladder by a modified glycosaminoglycan

Interstitial cystitis (IC), often referred to in combination with painful bladder syndrome, is a chronic inflammatory disease of the bladder. Current therapies primarily focus on replenishing urothelial glycosaminoglycan (GAG) layer using GAG analogs and managing pain with supportive therapies. However, the elusive etiology of IC and the lack of animal models to study the disease have been major hurdles developing more effective therapeutics. Previously, we showed an increased urinary concentration of antimicrobial peptide LL-37 in spina bifida patients and used LL-37 to develop a mouse model of cystitis that mimics important clinical findings of IC. Here we investigate (1) the molecular mechanism of LL-37 induced cystitis in cultured human urothelial cells and in mice, (2) the protective effects of GM-0111, a modified GAG, within the context of this mechanism, (3) the physiological and molecular markers that correlate with the severity of the inflammation, and (4) the protective effects of several GAGs using these biomarkers in our LL-37 induced cystitis model. We find that LL-37 quickly induces release of ATP and apoptosis in the urothelium. These changes can be inhibited by a chemically-modified GAG, GM-0111. Furthermore, we also find that GAG analogs provide varying degrees of protection against LL-37 challenge in mice. These findings suggest that GM-0111 and possibly GAG molecules prevent the development of cystitis by blocking the apoptosis and the concurrent release of ATP from the urothelium.

Exploiting differential surface display of chondroitin sulfate variants for directing neuronal outgrowth

Chondroitin sulfate (CS) proteoglycans (CSPGs) are known to be primary inhibitors of neuronal regeneration at scar sites. However, a variety of CSPGs are also involved in neuronal growth and guidance during other physiological stages. Sulfation patterns of CS chains influence their interactions with various growth factors in the central nervous system (CNS), thus influencing neuronal growth, inhibition, and pathfinding. This report demonstrates the use of differentially sulfated CS chains for neuronal navigation. Surface-immobilized patterns of CS glycosaminoglycan chains were used to determine neuronal preference toward specific sulfations of five CS variants: CS-A, CS-B (dermatan sulfate), CS-C, CS-D, and CS-E. Neurons preferred CS-A, CS-B, and CS-E and avoided CS-C containing lanes. In addition, significant alignment of neurites was observed using underlying lanes containing CS-A, CS-B, and CS-E chains. To utilize differential preference of neurons toward the CS variants, a binary combinations of CS chains were created by backfilling a neuro-preferred CS variant between the microcontact printed lanes of CS-C stripes, which are avoided by neurons. The neuronal outgrowth results demonstrate for the first time that a combination of sulfation variants of CS chains without any protein component of CSPG is sufficient for directing neuronal outgrowth. Biomaterials with surface immobilized GAG chains could find numerous applications as bridging devices for tackling CNS injuries where directional growth of neurons is critical for recovery.

A metabolically-stabilized phosphonate analog of lysophosphatidic acid attenuates collagen-induced arthritis

Rheumatoid arthritis (RA) is a destructive arthropathy with systemic manifestations, characterized by chronic synovial inflammation. Under the influence of the pro-inflammatory milieu synovial fibroblasts (SFs), the main effector cells in disease pathogenesis become activated and hyperplastic while releasing a number of signals that include pro-inflammatory factors and tissue remodeling enzymes. Activated RA SFs in mouse or human arthritic joints express significant quantities of autotaxin (ATX), a lysophospholipase D responsible for the majority of lysophosphatidic acid (LPA) production in the serum and inflamed sites. Conditional genetic ablation of ATX from SFs resulted in attenuation of disease symptoms in animal models, an effect attributed to diminished LPA signaling in the synovium, shown to activate SF effector functions. Here we show that administration of 1-bromo-3(S)-hydroxy-4-(palmitoyloxy)butyl-phosphonate (BrP-LPA), a metabolically stabilized analog of LPA and a dual function inhibitor of ATX and pan-antagonist of LPA receptors, attenuates collagen induced arthritis (CIA) development, thus validating the ATX/LPA axis as a novel therapeutic target in RA.

Cross-linked hydrogel and polyester resorbable ventilation tubes in a Chinchilla model

OBJECTIVES/HYPOTHESIS

To determine the resorption rate and biocompatibility characteristics of novel cross-linked hydrogel ventilation tubes and varied formulations of polyester ventilation tubes in a Chinchilla model.

STUDY DESIGN

Animal Study.

METHODS

Three cross-linked glycosaminoglycan hydrogel ventilation tubes fabricated by cross-linking thiol-modified chondroitin sulfate or thiol-modified carboxymethylated hyaluronic acid, four different polyester ventilation tubes (poly L-lactide [PLA], 50/50 poly D,L-lactide-co-glycolide [PLGA], and silver-impregnated versions of PLA and PLGA tubes) were placed into the tympanic membranes of chinchillas. Commercially available fluoroplastic ventilation tubes were placed in the contralateral ear of each animal to serve as a control. Integrity of the tubes was assessed by weekly otoscopy. Biocompatibility was assessed by auditory brainstem response, by otoscopic and histologic examination of the tympanic membrane at the tube site.

RESULTS

The hydrogel tubes had very short resorption times that expanded and enlarged the myringotomy site. PLGA and silver-coated PLGA tubes maintained their integrity in the tympanic membrane for similar durations of 18.9 ± 6.4 days and 21.0 ± 6.0 days, respectively. The silver-coated PLGA tubes had lower neutrophil and fibrosis scores than PLGA tubes. PLA tubes demonstrated equivalent findings to commercially available nonresorbable tubes with respect to otoscopic findings, auditory brainstem response thresholds, and histologic inflammatory scores.

CONCLUSIONS

Resorbable polyester pressure equalization tubes demonstrate predictable resorption behavior and similar biocompatibility characteristics when compared with nonresorbable tubes. Silver modification may confer some stability to PLGA tubes. Hydrogel tubes have very short resorption times, tend to enlarge the myringotomy site, and show greater inflammatory changes.

Physiological relevance of LL-37 induced bladder inflammation and mast cells

PURPOSE

We established the physiological relevance of LL-37 induced bladder inflammation. We hypothesized that 1) human urinary LL-37 is increased in pediatric patients with spina bifida, 2) LL-37 induced inflammation occurs in our mouse model via urothelial binding and is dose dependent and 3) LL-37 induced inflammation involves mast cells.

MATERIALS AND METHODS

To test our first hypothesis, we obtained urine samples from 56 pediatric patients with spina bifida and 22 normal patients. LL-37 was measured by enzyme-linked immunosorbent assay. Our second hypothesis was tested in C57Bl/6 mice challenged with 7 LL-37 concentrations intravesically for 1 hour. At 24 hours tissues were examined histologically and myeloperoxidase assay was done to quantitate inflammation. In separate experiments fluorescent LL-37 was instilled and tissues were obtained immediately (time = 0) and at 24 hours (time = 24). To test our final hypothesis, we performed immunohistochemistry for mast cell tryptase and evaluated 5 high power fields per bladder to determine the mean number of mast cells per mm(2).

RESULTS

Urinary LL-37 was 89-fold higher in patients with spina bifida. Mouse LL-37 dose escalation experiments revealed increased inflammation at higher LL-37 concentrations. Fluorescent LL-37 demonstrated global urothelial binding at time = 0 but was not visible at time = 24. Immunohistochemistry for tryptase revealed mast cell infiltration in all tissue layers. At higher concentrations the LL-37 challenge led to significantly greater mast cell infiltration.

CONCLUSIONS

Urinary LL-37 was significantly increased in pediatric patients with spina bifida. To our knowledge we report for the first time that LL-37 can elicit profound, dose dependent bladder inflammation involving the urothelium. Finally, inflammation propagation involves mast cells.

The translational imperative: making cell therapy simple and effective

The current practice of cell therapy, in which multipotent or terminally differentiated cells are injected into tissues or intravenously, is inefficient. Few therapeutic cells are retained at the site of administration and engraftment is low. An injectable and biologically appropriate vehicle for delivery, retention, growth and differentiation of therapeutic cells is needed to improve the efficacy of cell therapy. We focus on a hyaluronan-based semi-synthetic extracellular matrix (sECM), HyStem®, which is a manufacturable, approvable and affordable clinical product. The composition of this sECM can be customized for use with mesenchymal stem cells as well as cells derived from embryonic or induced pluripotent sources. In addition, it can support therapeutic uses of progenitor and mature cell populations obtained from skin, fat, liver, heart, muscle, bone, cartilage, nerves and other tissues. This overview presents four pre-clinical uses of HyStem® for cell therapy to repair injured vocal folds, improve post-myocardial infarct heart function, regenerate damaged liver tissue and restore brain function following ischemic stroke. Finally, we address the real-world limitations - manufacture, regulation, market acceptance and financing - surrounding cell therapy and the development of clinical combination products.

Pulmonary autotaxin expression contributes to the pathogenesis of pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive, fibrotic form of diffuse lung disease occurring mainly in older adults. Increased lysophosphatidic acid (LPA) concentrations have been reported in the alveolar space of both idiopathic pulmonary fibrosis patients and a corresponding animal model, whereas the genetic deletion or pharmacological inhibition of LPA receptor 1 attenuated the development of the modeled disease, suggesting a direct involvement of LPA in disease pathogenesis. In this report, increased concentrations of autotaxin (ATX; ENPP2), the enzyme largely responsible for extracellular LPA production, were detected in both murine and human fibrotic lungs. The genetic deletion of ATX from bronchial epithelial cells or macrophages attenuated disease severity, establishing ATX as a novel player in IPF pathogenesis. Furthermore, the pharmacological inhibition of ATX attenuated the development of the modeled disease, suggesting that ATX is a possible therapeutic target in IPF.

Hyaluronic acid-based hydrogels functionalized with heparin that support controlled release of bioactive BMP-2

Bone morphogenetic protein-2 (BMP-2) is a potent osteoinductive factor, yet its clinical use is limited by a short biological half-life, rapid local clearance and propensity for side effects. Heparin (HP), a highly sulfated glycosaminoglycan (GAG) that avidly binds BMP-2, has inherent biological properties that may circumvent these limitations. Here, we compared hyaluronan-based hydrogels formulated to include heparin (Heprasil™) with similar gels without heparin (Glycosil™) for their ability to deliver bioactive BMP-2 in vitro and in vivo. The osteogenic activity of BMP-2 released from the hydrogels was evaluated by monitoring alkaline phosphatase (ALP) activity and SMAD 1/5/8 phosphorylation in mesenchymal precursor cells. The osteoinductive ability of these hydrogels was determined in a rat ectopic bone model by 2D radiography, 3D μ-CT and histological analyses at 8 weeks post-implantation. Both hydrogels sustain the release of BMP-2. Importantly, the inclusion of a small amount of heparin (0.3% w/w) attenuated release of BMP-2 and sustained its osteogenic activity for up to 28 days. In contrast, hydrogels lacking heparin released more BMP-2 initially but were unable to maintain BMP-2 activity at later time points. Ectopic bone-forming assays using transplanted hydrogels emphasized the therapeutic importance of the initial burst of BMP-2 rather than its long-term osteogenic activity. Thus, tuning the burst release phase of BMP-2 from hydrogels may be advantageous for optimal bone formation.

Functional performance of human cardiosphere-derived cells delivered in an in situ polymerizable hyaluronan-gelatin hydrogel

The vast majority of cells delivered into the heart by conventional means are lost within the first 24 h. Methods are needed to enhance cell retention, so as to minimize loss of precious material and maximize effectiveness of the therapy. We tested a cell-hydrogel delivery strategy. Cardiosphere-derived cells (CDCs) were grown from adult human cardiac biopsy specimens. In situ polymerizable hydrogels made of hyaluronan and porcine gelatin (Hystem(®)-C™) were formulated as a liquid at room temperature so as to gel within 20 min at 37 °C. CDC viability and migration were not compromised in Hystem-C™. Myocardial infarction was created in SCID mice and CDCs were injected intramyocardially in the infarct border zone. Real-time PCR revealed engraftment of CDCs delivered in Hystem-C™ was increased by nearly an order of magnitude. LVEF (left ventricular ejection fraction) deteriorated in the control (PBS only) group over the 3-week time course. Hystem-C™ alone or CDCs alone preserved LVEF relative to baseline, while CDCs delivered in Hystem-C™ resulted in a sizable boost in LVEF. Heart morphometry revealed the greatest attenuation of LV remodeling in the CDC + Hystem-C™ group. Histological analysis suggested cardiovascular differentiation of the CDCs in Hystem-C™. However, the majority of functional benefit is likely from paracrine mechanisms such as tissue preservation and neovascularization. A CDC/hydrogel formulation suitable for catheter-based intramyocardial injection exhibits superior engraftment and functional benefits relative to naked CDCs.

Metabolically stabilized derivatives of phosphatidylinositol 4-phosphate: synthesis and applications

Phosphatidylinositol 4-phosphate (PtdIns(4)P) lipid is an essential component of eukaryotic membranes and a marker of the Golgi complex. Here, we developed metabolically stabilized (ms) analogs of PtdIns(4)P and the inositol 1,4-bisphosphate (IP(2)) head group derivative and demonstrated that these compounds can substitute the natural lipid fully retaining its physiological activities. The methylenephosphonate (MP) and phosphorothioate (PT) analogs of PtdIns(4)P and the aminohexyl (AH)-IP(2) probe are recognized by the PtdIns(4)P-specific PH domain of four phosphate adaptor protein 1 (FAPP1). Binding of FAPP1 to the PtdIns(4)P derivatives stimulates insertion of the PH domain into the lipid layers and induces tubulation of membranes. Both ms analogs and IP(2) probes could be invaluable for identifying protein effectors and characterizing PtdIns(4)P-dependent signaling cascades within the trans-Golgi network (TGN).

Therapeutic potential of gel-based injectables for vocal fold regeneration

Vocal folds are anatomically and biomechanically unique, thus complicating the design and implementation of tissue engineering strategies for repair and regeneration. Integration of an enhanced understanding of tissue biomechanics, wound healing dynamics and innovative gel-based therapeutics has generated enthusiasm for the notion that an efficacious treatment for vocal fold scarring could be clinically attainable within several years. Fibroblast phenotype and gene expression are mediated by the three-dimensional mechanical and chemical microenvironment at an injury site. Thus, therapeutic approaches need to coordinate spatial and temporal aspects of the wound healing response in an injured vocal tissue to achieve an optimal clinical outcome. Successful gel-based injectables for vocal fold scarring will require a keen understanding of how the native inflammatory response sets into motion the later extracellular matrix remodeling, which in turn will determine the ultimate biomechanical properties of the tissue. We present an overview of the challenges associated with this translation as well as the proposed gel-based injectable solutions.

Thiolated carboxymethyl-hyaluronic-Acid-based biomaterials enhance wound healing in rats, dogs, and horses

The progression of wound healing is a complicated but well-known process involving many factors, yet there are few products on the market that enhance and accelerate wound healing. This is particularly problematic in veterinary medicine where multiple species must be treated and large animals heal slower, oftentimes with complicating factors such as the development of exuberant granulation tissue. In this study a crosslinked-hyaluronic-acid (HA-) based biomaterial was used to treat wounds on multiple species: rats, dogs, and horses. The base molecule, thiolated carboxymethyl HA, was first found to increase keratinocyte proliferation in vitro. Crosslinked gels and films were then both found to enhance the rate of wound healing in rats and resulted in thicker epidermis than untreated controls. Crosslinked films were used to treat wounds on forelimbs of dogs and horses. Although wounds healed slower compared to rats, the films again enhanced wound healing compared to untreated controls, both in terms of wound closure and quality of tissue. This study indicates that these crosslinked HA-based biomaterials enhance wound healing across multiple species and therefore may prove particularly useful in veterinary medicine. Reduced wound closure times and better quality of healed tissue would decrease risk of infection and pain associated with open wounds.