N-glycosylation is one of the most important posttranslational modifications of proteins. It plays important roles in the biogenesis and functions of proteins by influencing their folding, ...intracellular localization, stability and solubility. N-glycans are synthesized by glycosyltransferases, a complex group of ubiquitous enzymes that occur in most kingdoms of life. A growing body of evidence shows that N-glycans may influence processing and functions of glycosyltransferases, including their secretion, stability and substrate/acceptor affinity. Changes in these properties may have a profound impact on glycosyltransferase activity. Indeed, some glycosyltransferases have to be glycosylated themselves for full activity. N-glycans and glycosyltransferases play roles in the pathogenesis of many diseases (including cancers), so studies on glycosyltransferases may contribute to the development of new therapy methods and novel glycoengineered enzymes with improved properties. In this review, we focus on the role of N-glycosylation in the activity of glycosyltransferases and attempt to summarize all available data about this phenomenon.
Necessary and sufficient conditions for uniform rotundity of Orlicz function spaces equipped with the p‐Amemiya norm (1≤p≤∞) are presented. The obtained results unify, complete and widen the ...characterization of uniform rotundity of Orlicz spaces. In the case of the ∞‐Amemiya (i.e. the Luxemburg) norm or the 1‐Amemiya (i.e. the Orlicz) norm, these results were known earlier. Some connections with the fixed point theory and the best approximation theory are presented.
Strict monotonicity, lower local uniform monotonicity, upper local uniform monotonicity and their orthogonal counterparts are considered in the case of Musielak–Orlicz function spaces
L
Φ
(
μ
)
...endowed with the Mazur–Orlicz F-norm as well as in the case of their subspaces
E
Φ
(
μ
)
with the F-norm induced from
L
Φ
(
μ
)
. The presented results generalize some of the results from Cui et al. (Aequ Math 93:311–343, 2019) and Hudzik et al. (J Nonlinear Convex Anal 17(10):1985–2011, 2016), obtained only for Orlicz spaces as well as their subspaces of order continuous elements equipped with the Mazur–Orlicz F-norm.
Some conditions which guarantee that the Orlicz function spaces equipped with the p-Amemiya norm (
1
<
p
<
∞
) and generated by N-functions are uniformly rotund in every direction are given. Obtained ...result broaden the knowledge about this notion in Orlicz function spaces with the p-Amemiya norm (
1
≤
p
≤
∞
).
We study properties of W01,p(R+,tβ) — the completion of C0∞(R+) in the power-weighted Sobolev spaces W1,p(R+,tβ), where β∈R. Among other results, we obtain the analytic characterization of ...W01,p(R+,tβ) for all β∈R. Our analysis is based on the precise study of the two trace operators: Tr0(u)≔limt→0u(t) and Tr∞(u)≔limt→∞u(t), which leads to the analysis of the asymptotic behavior of functions from W01,p(R+,tβ) near zero or infinity. The obtained statements can contribute to the proper formulation of Boundary Value Problems in ODEs, or PDEs with the radial symmetries. We can also apply our results to some questions in the complex interpolation theory, raised by Cwikel and Einav (2019), which we discuss within the particular case of Sobolev spaces W1,p(R+,tβ).
MicroRNAs (miRNAs) are small noncoding RNAs which mediate some of the pathological mechanisms of diabetic retinopathy. The aim of this study was to identify differentially expressed miRNAs in the ...vitreal exosomes of proliferative diabetic retinopathy (PDR) patients and non-diabetic controls. Exosomes were extracted from the vitreous samples of 10 PDR patients and 10 controls. The expression of 372 miRNAs was determined using a quantitative polymerase chain reaction (qPCR) panel. We have demonstrated a significant dysregulation in 26 miRNAs. The most remarkable findings include a profound attenuation of the miR-125 family, as well as enhanced miR-21-5p expression in the diabetic samples. We also showed the downregulation of miR-204-5p and the upregulation of let-7g in PDR compared to the controls. This study identified miR-125 and miR-21 as potential targets for further functional analysis regarding their putative role in the pathogenesis of PDR.
Eph Receptors and Ephrins in Retinal Diseases Kaczmarek, Radoslaw; Gajdzis, Pawel; Gajdzis, Malgorzata
International journal of molecular sciences,
06/2021, Letnik:
22, Številka:
12
Journal Article
Recenzirano
Odprti dostop
Retinal diseases are the leading cause of irreversible blindness. They affect people of all ages, from newborns in retinopathy of prematurity, through age-independent diabetic retinopathy and ...complications of retinal detachment, to age-related macular degeneration (AMD), which occurs mainly in the elderly. Generally speaking, the causes of all problems are disturbances in blood supply, hypoxia, the formation of abnormal blood vessels, and fibrosis. Although the detailed mechanisms underlying them are varied, the common point is the involvement of Eph receptors and ephrins in their pathogenesis. In our study, we briefly discussed the pathophysiology of the most common retinal diseases (diabetic retinopathy, retinopathy of prematurity, proliferative vitreoretinopathy, and choroidal neovascularization) and collected available research results on the role of Eph and ephrins. We also discussed the safety aspect of the use of drugs acting on Eph and ephrin for ophthalmic indications.
Glycosphingolipids (GSLs) are ubiquitous components of the cell membranes, found across several kingdoms of life, from bacteria to mammals, including humans. GSLs are a subclass of major glycolipids ...occurring in animal lipid membranes in clusters named “lipid rafts.” The most crucial functions of GSLs include signal transduction and regulation as well as participation in cell proliferation. Despite the mainstream view that pathogens rely on protein–protein interactions to survive and thrive in their hosts, many also target the host lipids. In particular, multiple pathogens produce adhesion molecules or toxins that bind GSLs. Attachment of pathogens to cell surface receptors is the initial step in infections. Many mammalian pathogens have evolved to recognize GSL-derived receptors. Animal glycosphingolipidomes consist of multiple types of GSLs differing in terminal glycan and ceramide structures in a cell or tissue-specific manner. Interspecies differences in GSLs dictate host specificity as well as cell and tissue tropisms. Evolutionary pressure exerted by pathogens on their hosts drives changes in cell surface glycoconjugates, including GSLs, and has produced a vast number of molecules and interaction mechanisms. Despite that abundance, the role of GSLs as pathogen receptors has been largely overlooked or only cursorily discussed. In this review, we take a closer look at GSLs and their role in the recognition, cellular entry, and toxicity of multiple bacterial, viral and fungal pathogens.
In this paper points of lower strict monotonicity, upper strict monotonicity, lower local uniform monotonicity and upper local uniform monotonicity of Orlicz function spaces equipped with a ...Mazur–Orlicz
F
-norm and generated by a monotone (non-convex in general) Orlicz function are studied. We show that both the necessary and sufficient conditions and the suitable theorems are formulated in full generality. Moreover, lower (upper) strict monotonicity and lower (upper) local uniform monotonicity theorems of the paper
https://doi.org/10.1007/s00010-018-0615-y
are revealed as corollaries in this paper.
The cornea, while appearing to be simple tissue, is actually an extremely complex structure. In order for it to retain its biomechanical and optical properties, perfect organization of its cells is ...essential. Proper regeneration is especially important after injuries and in the course of various diseases. Eph receptors and ephrin are mainly responsible for the proper organization of tissues as well as cell migration and communication. In this review, we present the current state of knowledge on the role of Eph and ephrins in corneal physiology and diseases, in particular, we focused on the functions of the epithelium and endothelium. Since the role of Eph and ephrins in the angiogenesis process has been well established, we also analyzed their influence on conditions with corneal neovascularization.
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