Human Wharton's Jelly Mesenchymal Stem Cell-Mediated Sciatic Nerve Recovery Is Associated with the Upregulation of Regulatory T Cells.

The acceleration of peripheral nerve regeneration is crucial for functional nerve recovery. Our previous study demonstrated that human Wharton's jelly-derived mesenchymal stem cells (hWJ-MSC) promote sciatic nerve recovery and regeneration via the direct upregulation and release of neurotrophic factors. However, the immunomodulatory role of hWJ-MSC in sciatic nerve recovery remains unclear. The effects of hWJ-MSC on innate immunity, represented by macrophages, natural killer cells, and dendritic cells, as well as on adaptive immunity, represented by CD4+ T, CD8+ T, B, and regulatory T cells (Tregs), were examined using flow cytometry. Interestingly, a significantly increased level of Tregs was detected in blood, lymph nodes (LNs), and nerve-infiltrating cells on POD7, 15, 21, and 35. Anti-inflammatory cytokines, such as IL-4 and IL-10, were significantly upregulated in the LNs and nerves of hWJ-MSC-treated mice. Treg depletion neutralized the improved effects of hWJ-MSC on sciatic nerve recovery. In contrast, Treg administration promoted the functional recovery of five-toe spread and gait stance. hWJ-MSC also expressed high levels of the anti-inflammatory cytokines TGF-ß and IL-35. This study indicated that hWJ-MSC induce Treg development to modulate the balance between pro- and anti-inflammation at the injured sciatic nerve by secreting higher levels of anti-inflammatory cytokines.

Crystal structure of cholesteryl ester transfer protein reveals a long tunnel and four bound lipid molecules.

Cholesteryl ester transfer protein (CETP) shuttles various lipids between lipoproteins, resulting in the net transfer of cholesteryl esters from atheroprotective, high-density lipoproteins (HDL) to atherogenic, lower-density species. Inhibition of CETP raises HDL cholesterol and may potentially be used to treat cardiovascular disease. Here we describe the structure of CETP at 2.2-A resolution, revealing a 60-A-long tunnel filled with two hydrophobic cholesteryl esters and plugged by an amphiphilic phosphatidylcholine at each end. The two tunnel openings are large enough to allow lipid access, which is aided by a flexible helix and possibly also by a mobile flap. The curvature of the concave surface of CETP matches the radius of curvature of HDL particles, and potential conformational changes may occur to accommodate larger lipoprotein particles. Point mutations blocking the middle of the tunnel abolish lipid-transfer activities, suggesting that neutral lipids pass through this continuous tunnel.

The Long-Term Efficacy Study of Multiple Allogeneic Canine Adipose Tissue-Derived Mesenchymal Stem Cells Transplantations Combined With Surgery in Four Dogs With Lumbosacral Spinal Cord Injury.

Severe lumbosacral pain, paraparesis or paraplegia, and urinary incontinence are common but frustrating problems in dogs with lumbosacral spinal cord injury (SCI). The surgical interventions including stabilization and decompression may not restore satisfying neurological functions in severe SCI. Adipose tissue-derived mesenchymal stem cells (Ad-MSCs) show benefits in immunomodulation, anti-inflammation, and promotion of axonal growth and remyelination, and also display efficacy in several diseases in veterinary medicine. In this report, four dogs presented with fracture of sacrum vertebrae or fracture of seventh lumbar and lumbosacral displacement after road traffic accidents. The clinical signs include lumbosacral pain (4/4), paraparesis (3/4), paraplegia (1/4), and urinary incontinence (4/4). All dogs were treated by surgical decompression with or without stabilization 1 to 7 weeks after trauma. Allogeneic canine Ad-MSCs (cAd-MSCs) were injected locally on nerve roots through the surgical region in all dogs. One dose of intravenous transplantation and 4 doses of local transplantation were also performed within 8 weeks after the surgery separately. All dogs showed significant neurological improvements with normal ambulatory ability (4/4) and urinary control (3/4) 3 months after the surgery and the first cAd-MSCs transplantation. No side effect was related to multiple cAd-MSCs transplantations during 6 months monitoring in all dogs. In conclusion, multiple cAd-MSCs transplantations could be a recommended treatment combined with surgery in dogs with lumbosacral SCI.

Assessment of cholesteryl ester transfer protein inhibitors for interaction with proteins involved in the immune response to infection.

The CETP inhibitor, torcetrapib, was prematurely terminated from phase 3 clinical trials due to an increase in cardiovascular and noncardiovascular mortality. Because nearly half of the latter deaths involved patients with infection, we have tested torcetrapib and other CETPIs to see if they interfere with lipopolysaccharide binding protein (LBP) or bactericidal/permeability increasing protein (BPI). No effect of these potent CETPIs on LPS binding to either protein was detected. Purified CETP itself bound weakly to LPS with a Kd >or= 25 microM compared with 0.8 and 0.5 nM for LBP and BPI, respectively, and this binding was not blocked by torcetrapib. In whole blood, LPS induced tumor necrosis factor-alpha normally in the presence of torcetrapib. Furthermore, LPS had no effect on CETP activity. We conclude that the sepsis-related mortality of the ILLUMINATE trial was unlikely due to a direct effect of torcetrapib on LBP or BPI function, nor to inhibition of an interaction of CETP with LPS. Instead, we speculate that the negative outcome seen for patients with infections might be related to the changes in plasma lipoprotein composition and metabolism, or alternatively to the known off-target effects of torcetrapib, such as aldosterone elevation, which may have aggravated the effects of sepsis.

A systematic study of 50S ribosomal subunit purification enabling robust crystallization.

A systematic analysis was undertaken to seek correlations between the integrity, purity and activity of 50S ribosomal subunit preparations from Deinococcus radiodurans and their ability to crystallize. Conditions of fermentation, purification and crystallization were varied in a search for crystals that could reliably supply an industrial X-ray crystallography program for the structure-based design of ribosomal antibiotics. A robust protocol was obtained to routinely obtain crystals that gave diffraction patterns extending to 2.9 A resolution and that were large enough to yield a complete data set from a single crystal. To our knowledge, this is the most systematic study of this challenging area so far undertaken. Ribosome crystallization is a complex multi-factorial problem and although a clear correlation of crystallization with subunit properties was not obtained, the search for key factors that potentiate crystallization has been greatly narrowed and promising areas for further inquiry are suggested.

Purification of the large ribosomal subunit via its association with the small subunit.

We have developed an affinity purification of the large ribosomal subunit from Deinococcus radiodurans that exploits its association with FLAG-tagged 30S subunits. Thus, capture is indirect so that no modification of the 50S is required and elution is achieved under mild conditions (low magnesium) that disrupt the association, avoiding the addition of competitor ligands or coelution of common contaminants. Efficient purification of highly pure 50S is achieved, and the chromatography simultaneously sorts the 50S into three classes according to their association status (unassociated, loosely associated, or tightly associated), improving homogeneity.

Modulation of Neural Differentiation through Submicron-Grooved Topography Surface with Modified Polydopamine.

Surface topography and bioactive molecules can generate physicochemical cues that control proliferation and differentiation of neural cells. In this study, polystyrene (PS) submicron-patterns with different widths (400 and 800 nm) and depths (100 and 400 nm) were prepared and subsequently modified with polydopamine (PDA) by a coating method. We examined neurites of PC12 cells and human adipose-derived stem cells (hADSCs) incubated in neuronal induction medium containing nerve growth factor (NGF) and basic fibroblast growth factor (bFGF), respectively. Then the differentiated cells on different grooved topographies were immunologically stained by Tuj-1 (a neuron marker) to compare the extent of neuronal differentiation. Our results showed that PC12 cells on grooved topography have predominantly bipolar neurite extension and align along the direction of the patterns, while flat surface has multipolar neurites. We demonstrated that the depths of topography have a strong impact on neurite outgrowth and alignment. In terms of the number of neurites, neurite length, and percentage of Tuj-1 positive cells, the 400/400 and 800/400 nm (widths/depths) PS grooves are appropriate for the cultivations of PC12 cells and hADSCs relative to those of other groups. In conclusion, the submicron-grooved topography and neurotrophic growth factors supported neurites outgrown and differentiated into neuron-like cells.

Topical Application of Human Wharton's Jelly Mesenchymal Stem Cells Accelerates Mouse Sciatic Nerve Recovery and is Associated with Upregulated Neurotrophic Factor Expression.

Peripheral nerve regeneration following injury is often slow and impaired, which results in weakened and denervated muscle with subsequent atrophy. Human Wharton's jelly mesenchymal stem cells (hWJ-MSC) have potential regenerative properties which, however, remain unknown in mouse nerve recovery. This study investigated the effect of the topical application of hWJ-MSC onto repairing transected sciatic nerves in a mouse model. Human adipocyte-derived stem cells (hADSC) were used as a positive control. The sciatic nerve of BALB/c mice was transected at a fixed point and repaired under the microscope using 10-0 sutures. hWJ-MSC and hADSC were applied to the site of repair and mice were followed up for 1 year. The hWJ-MSC group had significantly better functional recovery of five-toe spread and gait angles compared with the negative control and hADSC groups. hWJ-MSC improved sciatic nerve regeneration in a dose-dependent fashion. The hWJ-MSC group had a better quality of regenerated nerve with an increased number of myelinated axons throughout. hWJ-MSC appear to be safe in mice after 1 year of follow-up. hWJ-MSC also expressed higher levels of neurotrophic factor-3, brain-derived neurotrophic factor, and glial-derived neurotrophic factor than hADSC. hWJ-MSC may promote better nerve recovery than hADSC because of this upregulation of neurotrophic factors.

Pharmacologic inhibition of site 1 protease activity inhibits sterol regulatory element-binding protein processing and reduces lipogenic enzyme gene expression and lipid synthesis in cultured cells and experimental animals.

Sterol regulatory element-binding proteins (SREBPs) are major transcriptional regulators of cholesterol, fatty acid, and glucose metabolism. Genetic disruption of SREBP activity reduces plasma and liver levels of cholesterol and triglycerides and insulin-stimulated lipogenesis, suggesting that SREBP is a viable target for pharmacological intervention. The proprotein convertase SREBP site 1 protease (S1P) is an important posttranscriptional regulator of SREBP activation. This report demonstrates that 10 microM PF-429242 (Bioorg Med Chem Lett 17:4411-4414, 2007), a recently described reversible, competitive aminopyrrolidineamide inhibitor of S1P, inhibits endogenous SREBP processing in Chinese hamster ovary cells. The same compound also down-regulates the signal from an SRE-luciferase reporter gene in human embryonic kidney 293 cells and the expression of endogenous SREBP target genes in cultured HepG2 cells. In HepG2 cells, PF-429242 inhibited cholesterol synthesis, with an IC(50) of 0.5 microM. In mice treated with PF-429242 for 24 h, the expression of hepatic SREBP target genes was suppressed, and the hepatic rates of cholesterol and fatty acid synthesis were reduced. Taken together, these data establish that small-molecule S1P inhibitors are capable of reducing cholesterol and fatty acid synthesis in vivo and, therefore, represent a potential new class of therapeutic agents for dyslipidemia and for a variety of cardiometabolic risk factors associated with diabetes, obesity, and the metabolic syndrome.

A novel control scheme for inducing angiostatin-human IgG fusion protein production using recombinant CHO cells in a oscillating bioreactor.

In this study, a novel control scheme for inducing protein production using a recombinant CHO cell line in a BelloCell bioreactor was developed. This control scheme was applied in a simple regular semi-batch process. Production of angiostatin-human IgG fusion protein in a suspension recombinant CHO cell culture and a protein-free medium was used for this study. The bottom holding time (BH) was the sole operating variable to control the exposure time of the cells immobilized on the carriers to the air and allow the nutrient remained on the liquid film of the carriers to be consumed to a threshold level so that the cells can be arrested and promoted for protein production. In the cell cultures with various BH (1.5-90 min), final cell densities of 1.6-4.0 x 10(9) have been obtained in 20 days while total angiostatin-human IgG production of 228-388 mg have been harvested. In general, low BH will minimize the nutrient limitation and favor the cell growth, while high BH will restrict the nutrient and promote the production in this type of non-growth associated production systems. It was found that specific production rate was generally inversely proportional to the specific growth rate. In this case of study, BH of 30 and 60 min were found to be about 72% better than BH of 1.5 min and 35% better than BH of 9 and 90 min in term of the total angiostatin-human IgG production. In comparison to a conventional spinner flask study, a 3.8-fold increase of the total angiostatin-human IgG production was realized in a 35-day culture. This study illustrated that a simple method of using BH in a semi-batch process can effectively control the apparent nutrient concentration to the cells, and thus regulate the cell growth and protein production in a novel oscillating bioreactor.

Expression, purification, crystallization and structure of human adipocyte lipid-binding protein (aP2).

Human adipocyte lipid-binding protein (aP2) belongs to a family of intracellular lipid-binding proteins involved in the transport and storage of lipids. Here, the crystal structure of human aP2 with a bound palmitate is described at 1.5 A resolution. Unlike the known crystal structure of murine aP2 in complex with palmitate, this structure shows that the fatty acid is in a folded conformation and that the loop containing Phe57 acts as a lid to regulate ligand binding by excluding solvent exposure to the central binding cavity.

Anilinoquinazoline inhibitors of fructose 1,6-bisphosphatase bind at a novel allosteric site: synthesis, in vitro characterization, and X-ray crystallography.

The synthesis and in vitro structure-activity relationships (SAR) of a novel series of anilinoquinazolines as allosteric inhibitors of fructose-1,6-bisphosphatase (F16Bpase) are reported. The compounds have a different SAR as inhibitors of F16Bpase than anilinoquinazolines previously reported. Selective inhibition of F16Bpase can be attained through the addition of appropriate polar functional groups at the quinazoline 2-position, thus separating the F16Bpase inhibitory activity from the epidermal growth factor receptor tyrosine kinase inhibitory activity previously observed with similar structures. The compounds have been found to bind at a symmetry-repeated novel allosteric site at the subunit interface of the enzyme. Inhibition is brought about by binding to a loop comprised of residues 52-72, preventing the necessary participation of these residues in the assembly of the catalytic site. Mutagenesis studies have identified the key amino acid residues in the loop that are required for inhibitor recognition and binding.

Expression and protein chemistry yielding crystallization of the catalytic domain of ADAM17 complexed with a hydroxamate inhibitor.

The membrane-anchored metalloproteinase ADAM17 (TNF-alpha converting enzyme; TACE; EC 3.4.24.86) continues to be an attractive drug target in inflammatory diseases and cancer. Cocrystallization of its catalytic domain with a lead compound was complicated by the tenacious retention of the prodomain that has been shown to be enhanced if ADAM17 is expressed without the disintegrin/cysteine-rich domain that normally follows the N-terminal metalloproteinase. When a truncated form of ADAM17 composed of the signal peptide with the pro- and catalytic domains was expressed in baculovirus-infected insect cells, the major secreted product was a ternary complex of two prodomain fragments with the catalytic domain. The component polypeptides of the ternary complex were characterized by N-terminal analysis and mass spectrometry. Internal cleavage of the propeptide occurred following Arg-58, and a carboxypeptidase variably removed up to three basic residues from the newly created C-terminus. Cleavage at the C-terminus of the propeptide occurred after Arg-214. To prepare ADAM17 for crystal growth, a drug-like inhibitor was used to displace the propeptide and the complex of the catalytic domain with the inhibitor was isolated by size-exclusion chromatography and crystallized.

3-(2-carboxyethyl)-4,6-dichloro-1H-indole-2-carboxylic acid: an allosteric inhibitor of fructose-1,6-bisphosphatase at the AMP site.

3-(2-Carboxyethyl)-4,6-dichloro-1H-indole-2-carboxylic acid (MDL-29951), an antagonist of the glycine site of the NMDA receptor, has been found to be an allosteric inhibitor of the enzyme fructose 1,6-bisphosphatase. The compound binds at the AMP regulatory site by X-ray crystallography. This represents a new approach to inhibition of fructose 1,6-bisphosphatase and serves as a lead for further drug design.