Identifying Toll-like receptor expression in cutaneous sarcoidosis.

Toll-like receptors (TLRs) are known to be expressed in the skin. Antigenic stimulation of TLRs in the skin has been implicated in several inflammatory dermatologic diseases including psoriasis, syphilis, atopic dermatitis, and cutaneous T-cell lymphoma. However, the expression of TLRs in cutaneous sarcoidosis has not yet been defined. Expression of TLRs 1-9 was examined in cutaneous sarcoid by immunohistochemical staining. It was found that TLRs 5 and 6 stained most intensely in both the granulomas and epidermis of the sarcoid cases. TLRs 2, 3, 4, 7, and 8 stained more intensely compared with normal skin. All sarcoidosis cases showed an increased level of staining compared with the control. The nuclear factor-kappa B activation pathway was confirmed by staining for p65. All cases strongly stained for p65 in the granulomas and varied in staining intensity in the epidermis. The identified TLR expression in cutaneous sarcoidosis indicates that a bacterial antigen could be an etiologic agent of the disease. Future studies that clearly define the etiology of sarcoid will lead to better therapies and a better prognosis for affected patients.

Design and synthesis of conformationally constrained glucagon-like peptide-1 derivatives with increased plasma stability and prolonged in vivo activity.

A series of conformationally constrained derivatives of glucagon-like peptide-1 (GLP-1) were designed and evaluated. By use of [Gly (8)]GLP-1(7-37)-NH2 (2) peptide as a starting point, 17 cyclic derivatives possessing i to i + 4, i to i + 5, or i to i + 7 side chain to side chain lactam bridges from positions 18 to 30 were prepared. The effect of a helix-promoting alpha-amino-isobutyric acid (Aib) substitution at position 22 was also evaluated. The introduction of i to i + 4 glutamic acid-lysine lactam constraints in c[Glu (18)-Lys (22)][Gly (8)]GLP-1(7-37)-NH2 (6), c[Glu (22)-Lys (26)][Gly (8)]GLP-1(7-37)-NH2 (10), and c[Glu (23)-Lys (27)][Gly (8)]GLP-1(7-37)-NH2 (11) resulted in potent functional activity and receptor affinities comparable to native GLP-1. Selected GLP-1 peptides were chemoselectively PEGylated in order to prolong their in vivo activity. PEGylated peptides [Gly (8),Aib (22)]GLP-1(7-37)-Cys ((PEG))-Ala-NH2 (23) and c[Glu (22)-Lys (26)][Gly (8)]GLP-1(7-37)-Cys ((PEG))-Ser-Gly-NH2 (24) retained picomolar functional potency and avid receptor binding properties. Importantly, PEGylated GLP-1 peptide 23 exhibited sustained in vivo efficacy with respect to blood glucose reduction and decreased body weight for several days in nonhuman primates.

Raspberry ketone fails to reduce adiposity beyond decreasing food intake in C57BL/6 mice fed a high-fat diet.

As the incidence of obesity continues to increase, identifying novel nutritional therapies to enhance weight loss are needed. Raspberry ketone (RK; 4-(4-hydroxyphenyl) butan-2-one) is a bioactive phytochemical that is marketed as a weight loss supplement in the United States, yet there is scant scientific evidence demonstrating that RK promotes weight loss. The aim of the current study was to investigate the effect of RK on accumulation of adipose mass, hepatic lipid storage, and levels of plasma adiponectin in mice fed a high-fat (HF) diet. Mice were individually housed and fed a HF control diet (45% kcal from fat) for two weeks to induce weight gain, then assigned to HF control, high-dose (1.74% wt/wt) raspberry ketone (HRK), low-dose (0.25% wt/wt) raspberry ketone (LRK), or a pair-fed group (PF) fed similar food intake to LRK mice. Following five weeks of feeding, mice fed LRK and HRK diets showed reduced food intake and body weight compared to mice maintained on control diet. When normalized to body weight, mice fed HRK diet exhibited decreased inguinal fat mass and increased liver mass compared to the control group. Hepatic steatosis was lowest in mice fed HRK diet, whereas LRK diet did not have an effect when compared to the PF group. Plasma adiponectin concentration was unaffected by RK and pair-feeding. Our findings demonstrate that RK supplementation has limited benefit to adipose loss beyond reducing energy intake in mice fed a high-fat diet. The present study supports the need for appropriate study design when validating weight-loss supplements.

Oxidative folding of hepcidin at acidic pH.

Hepcidin is a four disulfide 25-residue peptide hormone which has a central role in the regulation of iron homeostasis. To support studies on hepcidin we have sought to establish reliable and robust synthetic methods for the preparation of correctly folded materials. While correctly-folded hepcidin has good aqueous solubility, we have found that its direct synthetic precursor, linear (reduced) hepcidin peptide, is resistant to solubilization, prone to precipitation at pH > or = 6, and thus difficult to fold efficiently. Attempts to directly fold either the crude or purified linear hepcidin peptide by air or DMSO oxidation methods under basic conditions were ineffective. However, addition of a glutathione redox pair system improved folding of purified linear hepcidin at mild basic pH (pH 7.5). Under acidic conditions, it was possible to oxidatively fold both crude and purified hepcidin using a polymer-supported oxidizing strategy. Peptide precipitation was also avoided under acidic conditions. Isolated folding yields of human hepcidin under acidic polymer-assisted conditions were superior to yields under basic folding conditions. These studies enabled identification of a reliable synthetic route for correctly-folded hepcidin.