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Simple Summary: Poultry are unable to synthesize arginine. Thus, it is essential to include enough arginine in poultry feed. One can save some arginine by means of providing the molecules in which arginine is needed as a building block. However, the question is how much arginine can these kinds of molecules replace in poultry feed. Herein, these questions are addressed in two trials comparing guanidinoacetic acid and arginine. Moreover, the energy-saving potential of guanidinoacetic acid is evaluated. Optimal performance in broiler chickens was achieved when birds were provided with higher dietary arginine content compared to the available recommendation tables. Supplementation of either arginine or guanidinoacetic acid with a low-arginine feed alleviated the lower performance. However, more guanidinoacetic acid was needed to provide the same level of growth attained with arginine (1 to 0.57 ratio). Reduction of dietary energy by 50 and 100 kcal/kg did not significantly influence the performance of birds at all stages of growth. Moreover, guanidinoacetic acid had no energy-sparing effect. This study helps the industry to accurately meet the arginine and energy requirements of broiler chickens. Two 35-day trials were conducted to determine the arginine (Arg) requirement of broiler chickens and the Arg and energy-sparing effects of guanidinoacetic acid (GAA). In experiment 1, a low-Arg diet (basal diet) was supplemented with increasing levels (0.06–0.61%) of L-Arg or GAA. In experiment 2, a diet meeting the energy and amino acid requirements of broiler chickens served as the positive control (PC). Two negative control (NC) groups were assigned by reducing either 50 (NC1) or 100 (NC2) kcal nitrogen-corrected metabolizable energy. Test groups were supplemented with 0.06% GAA for NC1 and 0.12% GAA for NC2 to compensate for the lower energy in the feed. The low dietary Arg concentration (starter: 1.02%, grower: 0.88%, finisher: 0.75%) significantly reduced overall performance (p < 0.05). Supplementation of either L-Arg or GAA with a low-Arg diet both alleviated the lower performance (p < 0.05). However, more GAA was needed to provide the same level of growth attained with L-Arg at an equivalency rate of 1 GAA to 0.57 Arg. Reduction of dietary energy by 50 and 100 kcal did not significantly influence the performance of birds at all stages of growth. Moreover, no effect of GAA supplementation at 0.06% or 0.12% was observed. [ABSTRACT FROM AUTHOR]

Invasive cancer cells develop small actin-based protrusions called invadopodia, which perform a primordial role in metastasis and extracellular matrix remodelling. Neural Wiskott-Aldrich syndrome protein (N-WASp) is a scaffold protein which can directly bind to actin monomers and Arp2/3 and is a crucial player in the formation of an invadopodium precursor. Expression modulation has pointed to an important role for N-WASp in invadopodium formation but the role of its C-terminal VCA domain in this process remains unknown. In this study, we generated alpaca nanobodies against the N-WASp VCA domain and investigated if these nanobodies affect invadopodium formation. By using this approach, we were able to study functions of a selected functional/structural N-WASp protein domain in living cells, without requiring overexpression, dominant negative mutants or siRNAs which target the gene, and hence the entire protein. When expressed as intrabodies, the VCA nanobodies significantly reduced invadopodium formation in both MDA-MB-231 breast cancer and HNSCC61 head and neck squamous cancer cells. Furthermore, expression of distinct VCA Nbs (VCA Nb7 and VCA Nb14) in PC-3 prostate cancer cells resulted in reduced overall matrix degradation without affecting MMP9 secretion/activation or MT1-MMP localisation at invadopodial membranes. From these results, we conclude that we have generated nanobodies targeting N-WASp which reduce invadopodium formation and functioning, most likely via regulation of N-WASp—Arp2/3 complex interaction, indicating that this region of N-WASp plays an important role in these processes. [ABSTRACT FROM AUTHOR]

Purpose: Gelsolin amyloidosis (AGel), also known as familial amyloidosis, Finnish type (FAF), is an autosomal, dominant, incurable disease caused by a point mutation (G654A/T) in the gelsolin (GSN) gene. The mutation results in loss of a Ca2+-binding site in the second gelsolin domain. Subsequent incorrect folding exposes a cryptic furin cleavage site, leading to the formation of a 68-kDa C-terminal cleavage product (C68) in the trans-Golgi network. This C68 fragment is cleaved by membrane type 1-matrix metalloproteinase (MT1-MMP) during secretion into the extracellular environment, releasing 8- and 5-kDa amyloidogenic peptides. These peptides aggregate and cause disease-associated symptoms. We set out to investigate whether AGel-specific nanobodies could be used to monitor amyloidogenic gelsolin buildup.Procedures: Three nanobodies (FAF Nb1-3) raised against the 8-kDa fragment were screened as AGel amyloid imaging agents in WT and AGel mice using 99mTc-based single-photon emission computed tomography (SPECT)/X-ray tomography (CT), biodistribution analysis, and immunofluorescence (IF). The quantitative characteristics were analyzed in a follow-up study with a Nb11-expressing mouse model.Results: All three nanobodies possess the characteristics desired for a 99mTc-based SPECT/CT imaging agent, high specificity and a low background signal. FAF Nb1 was identified as the most potent, based on its superior signal-to-noise ratio and signal specificity. As a proof of concept, we implemented 99mTc-FAF Nb1 in a follow-up study of the Nb11-expressing AGel mouse model. Using biodistribution analysis and immunofluorescence, we demonstrated the validity of the data acquired via 99mTc-FAF Nb1 SPECT/CT.Conclusion: These findings demonstrate the potential of this nanobody as a non-invasive tool to image amyloidogenic gelsolin deposition and assess the therapeutic capacity of AGel therapeutics currently under development. We propose that this approach can be extended to other amyloid diseases, thereby contributing to the development of specific therapies. [ABSTRACT FROM AUTHOR]