Sanja Dabelić | Faculty of Pharmacy and Biochemistry, University of Zagreb (original) (raw)

Papers by Sanja Dabelić

Biochemical and biological properties of glycoconjugates are strongly determined by the specifi c... more Biochemical and biological properties of glycoconjugates are strongly determined by the specifi c structure of its glycan parts. Glycosylation, the covalent attachment of sugars to proteins and lipids, is very complex and highly-coordinated process involving > 250 gene products. Defi ciency of glycosylation enzymes or transporters results in impaired glycosylation, and consequently pathological modulation of many physiological processes. Inborn defects of glycosylation enzymes, caused by the specifi c mutations, lead to the development of rare, but severe diseases -congenital disorders of glycosylation (CDGs). Up today, there are more than 45 known CDGs. Their clinical manifestations range from very mild to extremely severe (even lethal) and unfortunately, only three of them can be eff ectively treated nowadays. CDG symptoms highly vary, though some are common for several CDG types but also for other unrelated diseases, especially neurological ones, leaving the possibility that many CDGs cases are under-or misdiagnosed. Glycan analysis of serum transferrin (by isoelectric focusing or more sophisticated methods, such as HPLC (high-performance liquid chromatography) or MALDI (matrix-assisted laser desorption/ionization)) or serum N-glycans (by MS), enzyme activity assays and DNA sequence analysis are the most frequently used methods for CDG screening and identifi cation, since no specifi c tests are available yet. In this review we summarize the current knowledge on the clinical, biochemical and genetic characteristic of distinct CDGs, as well as existing diagnostic and therapeutic procedures, aiming to contribute to the awareness on the existence of these rare diseases and encourage the eff orts to elucidate its genetic background, improve diagnostics and develop new strategies for their treatment.

Galectins, an ancient lectin family, are characterized by specific binding of β-galactosides thro... more Galectins, an ancient lectin family, are characterized by specific binding of β-galactosides through evolutionary conserved sequence elements of carbohydrate-recognition domain (CRD). A structurally unique member of the family is galectin-3; in addition to the CRD it contains a prolineand glycine-rich N-terminal domain (ND) through which is able to form oligomers. Galectin-3 is widely spread among different types of cells and tissues, found intracellularly in nucleus and cytoplasm or secreted via non-classical pathway outside of cell, thus being found on the cell surface or in the extracellular space. Through specific interactions with a variety of intra-and extracellular proteins galectin-3 affects numerous biological processes and seems to be involved in different physiological and pathophysiological conditions, such as development, immune reactions, and neoplastic transformation and metastasis. The review attempts to summarize the existing information on structural, biochemical and intriguing functional properties of galectin-3.

During the last few decades, the effects of immunomodulatory drugs on numerous molecules and biol... more During the last few decades, the effects of immunomodulatory drugs on numerous molecules and biological processes have been widely studied. Nevertheless, the relationship between immunomodulatory drugs and lectin expression/function is still to be elucidated. In this study, we used THP-1-derived macrophages to investigate the effects of non-steroidal anti-inflammatory drugs (aspirin and indomethacin) and glucocorticoids (hydrocortisone and dexamethasone) on galectin-3, a multifunctional β-galactoside binding lectin, which in general acts as a strong pro-inflammatory signal. The results showed that all immunomodulatory drugs applied in clinically relevant doses affect both the gene (LGALS3) and protein expression level of galectin-3. The provoked changes on protein level are qualitatively and quantitatively different comparing to the effects on galectin-3 mRNA level, and depend on the differentiation state of the cell, drug type and applied concentration as well as on time of the exposure. Our data revealed galectin-3 as a new target molecule of immunomodulatory drugs, thus suggesting an additional pathway of their action on immune response.

Galectin-3, a b-galactoside binding lectin, acts as a strong pro-inflammatory signal. Many immuno... more Galectin-3, a b-galactoside binding lectin, acts as a strong pro-inflammatory signal. Many immunomodulatory drugs affect signaling pathways that comprise transcription factors involved in regulation of galectin-3 gene (LGALS3) expression. The aim of this study was to investigate the effects of non-steroidal anti-inflammatory drugs aspirin and indomethacin on the expression of galectin-3, both on mRNA and protein levels. The human monocytic cell line THP-1 was exposed to various therapeutic concentrations of aspirin and indomethacin for 72 hours. Relative RT-PCR method and the GeneScan analysis software were used for assessing the galectin-3 mRNA level and chemiluminescent-western blot analysis was used for measuring the galectin-3 level. The results showed that galectin-3 is a new target molecule of NSAIDs, which cause reduction of both gene and protein expression of galectin-3, but the intensity and time-course of the changes strongly depend on the kind and concentration of the drugs.

With the advance in typing tools and extraction procedures in recent years, DNA analysis has deve... more With the advance in typing tools and extraction procedures in recent years, DNA analysis has developed into an amazingly powerful method for forensic analysis. For a number of years, autosomal STR (Short Tandem Repeat) typing has been used as a tool in the process of identification of war victims in Croatia. Although DNA typing is very effective in detecting possible identities of exhumed skeletal remains, this approach bears some risk of false identification. The paper presents the case of a match between skeletal remains and the son and wife of a missing person in 13 STR loci. Even though these skeletal remains also matched in 13 loci the mother of the same missing person, additional genetic testing (Y-chromosome and mitochondrial DNA) unequivocally excluded the proposed identity. Although likelihood ratio is the best measure of the significance of a genetic match between exhumed skeletal remains and relatives of the missing person, the meaning of likelihood ratio is not as clear in database matching as in simple paternity cases and great care is needed to avoid wrong interpretation. To reduce the risk of possible false identifications, in addition to DNA evidence, other types of evidence (such as information about the time, place and other conditions of disappearance), as well as on anthropological and other »classical« forensic data are being used as a »control mechanism« in the DNA-lead process.

Background: Galectins have been identified as modulators of many monocyte/macrophage functions. I... more Background: Galectins have been identified as modulators of many monocyte/macrophage functions. In the response to a wide range of environmental cues macrophages may exhibit different biochemical and biological characteristics, but two main subtypes, classically (M1) and alternatively (M2) activated macrophages have been recognized. To contribute to elucidation of role and regulation of galectin-1 and galectin-3 in differently activated macrophages we explored their expression profiles in these cells. Methods: Human monocytes obtained from blood donors were differentiated into classically (M1) and alternatively (M2a/M2c) activated macrophages. Gene and protein expression levels of intra-and extracellular galectins were investigated by qRT-PCR, Western-blot, flow cytometry, and ELISA while cytokine and surface receptor expression profiling was performed by flow cytometry. Results: Differentiation/polarization of human monocytes into classically (M1) and alternatively (M2a/M2c) activated macrophages was followed by profound changes of galectin-3 expression and its proteolytic cleavage. Expression and secretion of Gal-3 was tightly regulated and significantly differed among classically (M1) and alternatively (M2a/M2c) activated macrophages, while the differences of galectin-1 expression profiles were not as pronounced. Human monocytes exhibited high amount of free galectin-3 receptors, while on both types of activated macrophages were fully saturated. Conclusions: Galectin-3 is more distinctive descriptor of macrophages differentiation/activation than galectin-1. Its specific expression and secretion pattern in M1 vs. M2a/M2c macrophages contributes to better understanding of its role and regulation in these cells. General significance: Recognition of distinct galectin-1 and galectin-3 expression profiles in differently activated macrophages provides a new insight on biological characteristics of these cells and sheds a new light of galectin-3 as a modulator of individual macrophage subset. This article is part of a Special Issue entitled Glycoproteomics.

Galectin-3, a structurally unique beta-galactosidebinding lectin, through the specific protein-pr... more Galectin-3, a structurally unique beta-galactosidebinding lectin, through the specific protein-protein and protein-carbohydrate interactions participates in numerous biological processes, such as cell proliferation and apoptosis, adhesion and activation. Its expression and secretion by until now an unknown mechanism are modulated by diverse molecules and are dependent on different physiological and pathophysiological conditions. By autocrine and paracrine actions, galectin-3 modulates many immune reactions and affects various immune cells, particularly those of monocyte-macrophage lineage. This is why galectin-3 has recently become an attractive therapeutic target. However, molecular mechanisms of its actions as well as regulatory mechanism of its expression and activation are still largely unknown. In this study, we show that lipopolysaccharide (LPS) provokes upregulation of galectin-3 expression on both gene and protein level in monocyte-like THP-1 cells, which can be inhibited by dexamethasone, but not with nonsteroidal anti-inflammatory drugs aspirin and indomethacin. Resting and LPS-challenged monocyte-like THP-1 cells do not have detectable amount of surface-bound galectin-3, but are able to bind exogenously added galectin-3 with the same capacity. Although galectin-3 is generally considered to be a pro-inflammatory molecule, here we show that the exogenously added galectin-3 does not affect interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-12p70 and TNF-α production in resting and LPS-activated monocyte-like THP-1 cells nor influences its own gene expression level in those cells.

Biochemical and biological properties of glycoconjugates are strongly determined by the specifi c... more Biochemical and biological properties of glycoconjugates are strongly determined by the specifi c structure of its glycan parts. Glycosylation, the covalent attachment of sugars to proteins and lipids, is very complex and highly-coordinated process involving > 250 gene products. Defi ciency of glycosylation enzymes or transporters results in impaired glycosylation, and consequently pathological modulation of many physiological processes. Inborn defects of glycosylation enzymes, caused by the specifi c mutations, lead to the development of rare, but severe diseases -congenital disorders of glycosylation (CDGs). Up today, there are more than 45 known CDGs. Their clinical manifestations range from very mild to extremely severe (even lethal) and unfortunately, only three of them can be eff ectively treated nowadays. CDG symptoms highly vary, though some are common for several CDG types but also for other unrelated diseases, especially neurological ones, leaving the possibility that many CDGs cases are under-or misdiagnosed. Glycan analysis of serum transferrin (by isoelectric focusing or more sophisticated methods, such as HPLC (high-performance liquid chromatography) or MALDI (matrix-assisted laser desorption/ionization)) or serum N-glycans (by MS), enzyme activity assays and DNA sequence analysis are the most frequently used methods for CDG screening and identifi cation, since no specifi c tests are available yet. In this review we summarize the current knowledge on the clinical, biochemical and genetic characteristic of distinct CDGs, as well as existing diagnostic and therapeutic procedures, aiming to contribute to the awareness on the existence of these rare diseases and encourage the eff orts to elucidate its genetic background, improve diagnostics and develop new strategies for their treatment.

Galectins, an ancient lectin family, are characterized by specific binding of β-galactosides thro... more Galectins, an ancient lectin family, are characterized by specific binding of β-galactosides through evolutionary conserved sequence elements of carbohydrate-recognition domain (CRD). A structurally unique member of the family is galectin-3; in addition to the CRD it contains a prolineand glycine-rich N-terminal domain (ND) through which is able to form oligomers. Galectin-3 is widely spread among different types of cells and tissues, found intracellularly in nucleus and cytoplasm or secreted via non-classical pathway outside of cell, thus being found on the cell surface or in the extracellular space. Through specific interactions with a variety of intra-and extracellular proteins galectin-3 affects numerous biological processes and seems to be involved in different physiological and pathophysiological conditions, such as development, immune reactions, and neoplastic transformation and metastasis. The review attempts to summarize the existing information on structural, biochemical and intriguing functional properties of galectin-3.

During the last few decades, the effects of immunomodulatory drugs on numerous molecules and biol... more During the last few decades, the effects of immunomodulatory drugs on numerous molecules and biological processes have been widely studied. Nevertheless, the relationship between immunomodulatory drugs and lectin expression/function is still to be elucidated. In this study, we used THP-1-derived macrophages to investigate the effects of non-steroidal anti-inflammatory drugs (aspirin and indomethacin) and glucocorticoids (hydrocortisone and dexamethasone) on galectin-3, a multifunctional β-galactoside binding lectin, which in general acts as a strong pro-inflammatory signal. The results showed that all immunomodulatory drugs applied in clinically relevant doses affect both the gene (LGALS3) and protein expression level of galectin-3. The provoked changes on protein level are qualitatively and quantitatively different comparing to the effects on galectin-3 mRNA level, and depend on the differentiation state of the cell, drug type and applied concentration as well as on time of the exposure. Our data revealed galectin-3 as a new target molecule of immunomodulatory drugs, thus suggesting an additional pathway of their action on immune response.

Galectin-3, a b-galactoside binding lectin, acts as a strong pro-inflammatory signal. Many immuno... more Galectin-3, a b-galactoside binding lectin, acts as a strong pro-inflammatory signal. Many immunomodulatory drugs affect signaling pathways that comprise transcription factors involved in regulation of galectin-3 gene (LGALS3) expression. The aim of this study was to investigate the effects of non-steroidal anti-inflammatory drugs aspirin and indomethacin on the expression of galectin-3, both on mRNA and protein levels. The human monocytic cell line THP-1 was exposed to various therapeutic concentrations of aspirin and indomethacin for 72 hours. Relative RT-PCR method and the GeneScan analysis software were used for assessing the galectin-3 mRNA level and chemiluminescent-western blot analysis was used for measuring the galectin-3 level. The results showed that galectin-3 is a new target molecule of NSAIDs, which cause reduction of both gene and protein expression of galectin-3, but the intensity and time-course of the changes strongly depend on the kind and concentration of the drugs.

With the advance in typing tools and extraction procedures in recent years, DNA analysis has deve... more With the advance in typing tools and extraction procedures in recent years, DNA analysis has developed into an amazingly powerful method for forensic analysis. For a number of years, autosomal STR (Short Tandem Repeat) typing has been used as a tool in the process of identification of war victims in Croatia. Although DNA typing is very effective in detecting possible identities of exhumed skeletal remains, this approach bears some risk of false identification. The paper presents the case of a match between skeletal remains and the son and wife of a missing person in 13 STR loci. Even though these skeletal remains also matched in 13 loci the mother of the same missing person, additional genetic testing (Y-chromosome and mitochondrial DNA) unequivocally excluded the proposed identity. Although likelihood ratio is the best measure of the significance of a genetic match between exhumed skeletal remains and relatives of the missing person, the meaning of likelihood ratio is not as clear in database matching as in simple paternity cases and great care is needed to avoid wrong interpretation. To reduce the risk of possible false identifications, in addition to DNA evidence, other types of evidence (such as information about the time, place and other conditions of disappearance), as well as on anthropological and other »classical« forensic data are being used as a »control mechanism« in the DNA-lead process.

Background: Galectins have been identified as modulators of many monocyte/macrophage functions. I... more Background: Galectins have been identified as modulators of many monocyte/macrophage functions. In the response to a wide range of environmental cues macrophages may exhibit different biochemical and biological characteristics, but two main subtypes, classically (M1) and alternatively (M2) activated macrophages have been recognized. To contribute to elucidation of role and regulation of galectin-1 and galectin-3 in differently activated macrophages we explored their expression profiles in these cells. Methods: Human monocytes obtained from blood donors were differentiated into classically (M1) and alternatively (M2a/M2c) activated macrophages. Gene and protein expression levels of intra-and extracellular galectins were investigated by qRT-PCR, Western-blot, flow cytometry, and ELISA while cytokine and surface receptor expression profiling was performed by flow cytometry. Results: Differentiation/polarization of human monocytes into classically (M1) and alternatively (M2a/M2c) activated macrophages was followed by profound changes of galectin-3 expression and its proteolytic cleavage. Expression and secretion of Gal-3 was tightly regulated and significantly differed among classically (M1) and alternatively (M2a/M2c) activated macrophages, while the differences of galectin-1 expression profiles were not as pronounced. Human monocytes exhibited high amount of free galectin-3 receptors, while on both types of activated macrophages were fully saturated. Conclusions: Galectin-3 is more distinctive descriptor of macrophages differentiation/activation than galectin-1. Its specific expression and secretion pattern in M1 vs. M2a/M2c macrophages contributes to better understanding of its role and regulation in these cells. General significance: Recognition of distinct galectin-1 and galectin-3 expression profiles in differently activated macrophages provides a new insight on biological characteristics of these cells and sheds a new light of galectin-3 as a modulator of individual macrophage subset. This article is part of a Special Issue entitled Glycoproteomics.

Galectin-3, a structurally unique beta-galactosidebinding lectin, through the specific protein-pr... more Galectin-3, a structurally unique beta-galactosidebinding lectin, through the specific protein-protein and protein-carbohydrate interactions participates in numerous biological processes, such as cell proliferation and apoptosis, adhesion and activation. Its expression and secretion by until now an unknown mechanism are modulated by diverse molecules and are dependent on different physiological and pathophysiological conditions. By autocrine and paracrine actions, galectin-3 modulates many immune reactions and affects various immune cells, particularly those of monocyte-macrophage lineage. This is why galectin-3 has recently become an attractive therapeutic target. However, molecular mechanisms of its actions as well as regulatory mechanism of its expression and activation are still largely unknown. In this study, we show that lipopolysaccharide (LPS) provokes upregulation of galectin-3 expression on both gene and protein level in monocyte-like THP-1 cells, which can be inhibited by dexamethasone, but not with nonsteroidal anti-inflammatory drugs aspirin and indomethacin. Resting and LPS-challenged monocyte-like THP-1 cells do not have detectable amount of surface-bound galectin-3, but are able to bind exogenously added galectin-3 with the same capacity. Although galectin-3 is generally considered to be a pro-inflammatory molecule, here we show that the exogenously added galectin-3 does not affect interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-12p70 and TNF-α production in resting and LPS-activated monocyte-like THP-1 cells nor influences its own gene expression level in those cells.