Herynek, Štěpán* Dotaz Zobrazit nápovědu
OBJECTIVE: The aim of our study was to compare the effects of a vegetarian and a conventional diet on thigh adipose tissue distribution in subjects with type 2 diabetes (T2D). METHODS: Seventy-four subjects with T2D were randomly assigned to either follow a vegetarian diet (V, n = 37) or a control group who followed an isocaloric conventional anti-diabetic diet (C, n = 37). Both diets were calorie restricted (-500 kcal/day). To measure insulin sensitivity, the hyperinsulinemic (1 mU.kg-1.min-1) isoglycemic clamp was conducted. β-Cell function was assessed using a mathematical model after a test meal. Magnetic resonance imaging of the thigh was performed. All subjects were examined at 0, 3, and 6 months. Statistical analyses were performed using repeated measures analysis of variance and a multivariate regression model. RESULTS: Greater reduction was observed in total leg area in V (-13.6 cm2 [95% confidence interval [CI], -14.2 to -12.9] in V vs -9.9 cm2 [95% CI, -10.6 to -9.2] in C; Gxt p < 0.001). The reduction in subcutaneous fat was comparable in response to both diets (Gxt, p = 0.64). Subfascial fat was reduced only in response to a vegetarian diet (-0.82 [95% CI, -1.13 to -0.55] cm2 in V vs -0.44 [95% CI, -0.78 to +0.02] cm2 in C; Gxt, p = 0.04). The reduction in intramuscular fat tended to be greater in response to a vegetarian diet (-1.78 [95% CI, -2.26 to -1.27] cm2 in V vs -0.57 [95% CI, -1.06 to -0.09] cm2 in C; Gxt, p = 0.12). Changes in subcutaneous and subfascial fat correlated with changes in glycated hemoglobin (HbA1c), fasting plasma glucose, and β-cell insulin sensitivity. After adjustment for changes in body mass index (BMI), correlations remained significant for changes in fasting plasma glucose and β-cell insulin sensitivity and with changes in triglycerides. CONCLUSIONS: Our data indicate the importance of both subcutaneous and subfascial fat in relationship to glucose and lipid metabolism. ABBREVIATIONS: BMI , body mass index; C , control group; FPG , fasting plasma glucose; Gxt , interaction between group and time; HbA1c , glycated hemoglobin; MCR , metabolic clearance rate of glucose; OPLS , orthogonal projections to latent structure; T2D , type 2 diabetes; V , vegetarian group.
- Klíčová slova
- Insulin sensitivity, intramuscular fat, thigh adipose tissue, type 2 diabetes, vegetarian diet,
- MeSH
- diabetes mellitus 2. typu dietoterapie MeSH
- dieta vegetariánská * MeSH
- distribuce tělesného tuku * MeSH
- dospělí MeSH
- energetický příjem MeSH
- kalorická restrikce * MeSH
- lidé MeSH
- tuková tkáň fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- randomizované kontrolované studie MeSH
We combined cell-free ribosome display and cell-based yeast display selection to build specific protein binders to the extracellular domain of the human interleukin 9 receptor alpha (IL-9Rα). The target, IL-9Rα, is the receptor involved in the signalling pathway of IL-9, a pro-inflammatory cytokine medically important for its involvement in respiratory diseases. The successive use of modified protocols of ribosome and yeast displays allowed us to combine their strengths-the virtually infinite selection power of ribosome display and the production of (mostly) properly folded and soluble proteins in yeast display. The described experimental protocol is optimized to produce binders highly specific to the target, including selectivity to common proteins such as BSA, and proteins potentially competing for the binder such as receptors of other cytokines. The binders were trained from DNA libraries of two protein scaffolds called 57aBi and 57bBi developed in our laboratory. We show that the described unconventional combination of ribosome and yeast displays is effective in developing selective small protein binders to the medically relevant molecular target.
- Klíčová slova
- directed evolution, interleukin 9 receptor alpha, protein scaffolds, ribosome display, yeast display,
- MeSH
- cytokiny MeSH
- lidé MeSH
- peptidová knihovna MeSH
- receptory interleukinu-9 MeSH
- Saccharomyces cerevisiae * genetika MeSH
- transportní proteiny * MeSH
- vazba proteinů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- cytokiny MeSH
- peptidová knihovna MeSH
- receptory interleukinu-9 MeSH
- transportní proteiny * MeSH
Cytoskeletal rearrangements and crosstalk between microtubules and actin filaments are vital for living organisms. Recently, an abundantly present microtubule polymerase, CKAP5 (XMAP215 homolog), has been reported to play a role in mediating crosstalk between microtubules and actin filaments in the neuronal growth cones. However, the molecular mechanism of this process is unknown. Here, we demonstrate, in a reconstituted system, that CKAP5 enables the formation of persistent actin bundles templated by dynamically instable microtubules. We explain the templating by the difference in CKAP5 binding to microtubules and actin filaments. Binding to the microtubule lattice with higher affinity, CKAP5 enables the formation of actin bundles exclusively on the microtubule lattice, at CKAP5 concentrations insufficient to support any actin bundling in the absence of microtubules. Strikingly, when the microtubules depolymerize, actin bundles prevail at the positions predetermined by the microtubules. We propose that the local abundance of available CKAP5-binding sites in actin bundles allows the retention of CKAP5, resulting in persisting actin bundles. In line with our observations, we found that reducing CKAP5 levels in vivo results in a decrease in actin-microtubule co-localization in growth cones and specifically decreases actin intensity at microtubule plus ends. This readily suggests a mechanism explaining how exploratory microtubules set the positions of actin bundles, for example, in cytoskeleton-rich neuronal growth cones.
- Klíčová slova
- CKAP5, XMAP215, actin filaments, cytoskeleton, cytoskeleton-associated proteins, filament crosslinkers, in vitro reconstitution, microtubules, neuronal growth cones,
- MeSH
- aktiny * metabolismus MeSH
- čípky retiny metabolismus MeSH
- cytoskelet metabolismus MeSH
- mikrofilamenta metabolismus MeSH
- mikrotubuly * metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
- Názvy látek
- aktiny * MeSH
Microtubules (MTs) are dynamically unstable polar biopolymers switching between periods of polymerization and depolymerization, with the switch from the polymerization to the depolymerization phase termed catastrophe and the reverse transition termed rescue.1 In presence of MT-crosslinking proteins, MTs form parallel or anti-parallel overlaps and self-assemble reversibly into complex networks, such as the mitotic spindle. Differential regulation of MT dynamics in parallel and anti-parallel overlaps is critical for the self-assembly of these networks.2,3 Diffusible MT crosslinkers of the Ase1/MAP65/PRC1 family associate with different affinities to parallel and antiparallel MT overlaps, providing a basis for this differential regulation.4,5,6,7,8,9,10,11 Ase1/MAP65/PRC1 family proteins directly affect MT dynamics12 and recruit other proteins that locally alter MT dynamics, such as CLASP or kinesin-4.7,13,14,15,16 However, how Ase1 differentially regulates MT stability in parallel and antiparallel bundles is unknown. Here, we show that Ase1 selectively promotes antiparallel MT overlap longevity by slowing down the depolymerization velocity and by increasing the rescue frequency, specifically in antiparallelly crosslinked MTs. At the retracting ends of depolymerizing MTs, concomitant with slower depolymerization, we observe retention and accumulation of Ase1 between crosslinked MTs and on isolated MTs. We hypothesize that the ability of Ase1 to reduce the dissociation of tubulin subunits is sufficient to promote its enrichment at MT ends. A mathematical model built on this idea shows good agreement with the experiments. We propose that differential regulation of MT dynamics by Ase1 contributes to mitotic spindle assembly by specifically stabilizing antiparallel overlaps, compared to parallel overlaps or isolated MTs.
- Klíčová slova
- Ase1/PRC1/MAP65 crosslinkers, diffusible microtubule crosslinkers, microtubule arrays, microtubule dynamics, microtubule overlap stability, microtubules,
- MeSH
- aparát dělícího vřeténka metabolismus MeSH
- mikrotubuly * metabolismus MeSH
- proteiny asociované s mikrotubuly * metabolismus genetika MeSH
- Saccharomyces cerevisiae - proteiny metabolismus genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- Ase1 protein, S cerevisiae MeSH Prohlížeč
- proteiny asociované s mikrotubuly * MeSH
- Saccharomyces cerevisiae - proteiny MeSH
Here, we present a previously undescribed approach to modify N-terminal sequences of recombinant proteins to increase their production yield in Escherichia coli. Prior research has demonstrated that the nucleotides immediately following the start codon can significantly influence protein expression. However, the impact of these sequences is construct-specific and is not universally applicable to all proteins. Most of the previous research has been limited to selecting from a few rationally designed sequences. In contrast, we used a directed evolution-based methodology, screening large numbers of diversified sequences derived from DNA libraries coding for the N-termini of investigated proteins. To facilitate the identification of cells with increased expression of the target construct, we cloned a GFP gene at the C-terminus of the expressed genes and used fluorescent activated cell sorting (FACS) to separate cells based on their fluorescence. By following this systematic workflow, we successfully elevated the yield of soluble recombinant proteins of multiple constructs up to over 30-fold.
- Klíčová slova
- DNA libraries, N‐terminal sequences, directed evolution, fluorescence‐activated cell sorting (FACS), protein expression optimization,
- Publikační typ
- časopisecké články MeSH
Neurons in the CNS lose regenerative potential with maturity, leading to minimal corticospinal tract (CST) axon regrowth after spinal cord injury (SCI). In young rodents, knockdown of PTEN, which antagonizes PI3K signaling by hydrolyzing PIP3, promotes axon regeneration following SCI. However, this effect diminishes in adults, potentially due to lower PI3K activation leading to reduced PIP3. This study explores whether increased PIP3 generation can promote long-distance regeneration in adults. We used a hyperactive PI3K, PI3Kδ (PIK3CD), to boost PIP3 levels in mature cortical neurons and assessed CST regeneration after SCI. Adult rats received AAV1-PIK3CD and AAV1-eGFP, or AAV1-eGFP alone, in the sensorimotor cortex concurrent with a C4 dorsal SCI. Transduced neurons showed increased pS6 levels, indicating elevated PI3K/Akt/mTOR signaling. CST regeneration, confirmed with retrograde tracing, was evaluated up to 16 weeks post injury. At 12 weeks, ∼100 axons were present at lesion sites, doubling to 200 by 16 weeks, with regeneration indices of 0.1 and 0.2, respectively. Behavioral tests showed significant improvements in paw reaching, grip strength, and ladder-rung walking in PIK3CD-treated rats, corroborated by electrophysiological recordings of cord dorsum potentials and distal flexor muscle electromyography. Thus, PI3Kδ upregulation in adult cortical neurons enhances axonal regeneration and functional recovery post SCI.
- Klíčová slova
- CST, PI3K, axon regeneration, c-Fos, electrophysiology, pS6, signaling, skilled paw reaching, spinal cord, spinal cord injury,
- MeSH
- axony metabolismus fyziologie MeSH
- Dependovirus genetika MeSH
- fosfatidylinositol-3-kinasy třídy I metabolismus genetika MeSH
- fosfatidylinositol-3-kinasy metabolismus MeSH
- genetické vektory genetika MeSH
- krysa rodu Rattus MeSH
- modely nemocí na zvířatech MeSH
- neurony metabolismus MeSH
- obnova funkce MeSH
- poranění míchy * metabolismus terapie genetika MeSH
- pyramidové dráhy * metabolismus MeSH
- regenerace nervu * MeSH
- signální transdukce MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- fosfatidylinositol-3-kinasy třídy I MeSH
- fosfatidylinositol-3-kinasy MeSH
Engineered small non-antibody protein scaffolds are a promising alternative to antibodies and are especially attractive for use in protein therapeutics and diagnostics. The advantages include smaller size and a more robust, single-domain structural framework with a defined binding surface amenable to mutation. This calls for a more systematic approach in designing new scaffolds suitable for use in one or more methods of directed evolution. We hereby describe a process based on an analysis of protein structures from the Protein Data Bank and their experimental examination. The candidate protein scaffolds were subjected to a thorough screening including computational evaluation of the mutability, and experimental determination of their expression yield in E. coli, solubility, and thermostability. In the next step, we examined several variants of the candidate scaffolds including their wild types and alanine mutants. We proved the applicability of this systematic procedure by selecting a monomeric single-domain human protein with a fold different from previously known scaffolds. The newly developed scaffold, called ProBi (Protein Binder), contains two independently mutable surface patches. We demonstrated its functionality by training it as a binder against human interleukin-10, a medically important cytokine. The procedure yielded scaffold-related variants with nanomolar affinity.
- Klíčová slova
- computational saturation, directed evolution, interleukin-10, protein engineering, protein scaffold, ribosome display,
- MeSH
- databáze proteinů MeSH
- interleukin-10 metabolismus MeSH
- konformace proteinů MeSH
- počítačová simulace MeSH
- proteinové inženýrství MeSH
- proteiny chemie genetika metabolismus MeSH
- rekombinantní proteiny chemie genetika metabolismus MeSH
- ribozomy metabolismus MeSH
- řízená evoluce molekul metody MeSH
- sekvence aminokyselin MeSH
- stabilita proteinů MeSH
- vazba proteinů MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- interleukin-10 MeSH
- proteiny MeSH
- rekombinantní proteiny MeSH