Papers by Massimo U . De Martino
The FASEB Journal, Jun 17, 2003
L-Carnitine is an essential nutrient with a major role in cellular energy production. There is ev... more L-Carnitine is an essential nutrient with a major role in cellular energy production. There is evidence that, at high doses, L-carnitine might mimic some of the biological activities of glucocorticoids, especially immunomodulation. To explore the molecular basis of this effect, we tested the influence of L-carnitine on glucocorticoid receptor-α (GRα) functions. Millimolar concentrations of L-carnitine, which were not cytotoxic in vitro, significantly reduced the whole cell binding of [ 3 H]dexamethasone to GRα by decreasing the affinity of this receptor for its steroid ligand. At the same concentrations, L-carnitine was able to trigger nuclear translocation of green fluorescent protein (GFP)-fused human GRα and transactivate the glucocorticoidresponsive mouse mammary tumor virus (MMTV) and TAT3 promoters in a dose-dependent fashion. This effect was solely dependent on the presence of glucocorticoid-responsive elements on the promoter and on the expression of functional GRα by the cell. Finally, similarly to glucocorticoids, L-carnitine suppressed tumor necrosis factor-α (TNFα) and interleukin-12 release by human primary monocytes stimulated with lipopolysaccharide ex vivo. Both GRα transactivation and cytokine suppression by L-carnitine were abrogated by the GRα-antagonist RU 486. Taken together, our results suggest that pharmacological doses of L-carnitine can activate GRα and, through this mechanism, regulate glucocorticoid-responsive genes, potentially sharing some of the biological and therapeutic properties of glucocorticoids. Key words: GR • immunity • cytokines-Carnitine (3-hydroxy-4-N,N,N-trimethylaminobutyrate) is a quaternary amine present in all animal species, as well as in several microorganisms and in some higher plants (1, 2). In humans, L-carnitine is synthesized only in small amounts by the liver, kidney, and brain (3, 4). Therefore, most of L-carnitine in the human body is derived from the diet, particularly red meat, fish, and dairy products (4). The main physiological role of L-carnitine is to drive short-, medium-, and long-chained free fatty acids through cell compartments as acyl-carnitine esters. Transfer of acyl groups in this L
Annals of the New York Academy of Sciences, Jun 1, 2004
L-Carnitine (LC) is a nutrient with an essential role in cellular energy production. At high dose... more L-Carnitine (LC) is a nutrient with an essential role in cellular energy production. At high doses, LC can mimic some of the biological activities of glucocorticoids, particularly immunomodulation. To explore the molecular bases of this property, we tested the influence of LC on glucocorticoid receptora (GRa) functions. LC reduced the binding capacity of GRa, induced its nuclear translocation, and stimulated its transcriptional activity. Moreover, LC suppressed TNFrv and IL-12 release from human monocytes in glucocorticoidlike fashion. We conclude that pharmacologic doses of LC can activate GRrv and, via this mechanism, regulate glucocorticoid-responsive genes, potentially sharing some of the biological and therapeutic properties of glucocorticoids.
Steroids, Nov 1, 2006
Glucocorticoids (GC) by either up-regulating or down-regulating the expression of genes influence... more Glucocorticoids (GC) by either up-regulating or down-regulating the expression of genes influence cellular processes in every tissue and organ of the body. The enzyme 11hydroxysteroid dehydrogenase Type-1 (11-HSD-1) confers bioactivity upon the inactive GC cortisone (E) and prednisone (P) by converting them to cortisol (F) and prednisolone (L), respectively. We sought to investigate whether gene expression modulation by GC is under the regulation of an intracrine mechanism that determines the intracellular concentration of active GC. Human cell lines were transiently and stably co-transfected with an expression construct for 11-HSD-1 and a GC-responsive reporter gene and incubated with active and inactive GC. Whereas in cells that were not transfected with the expression construct for 11-HSD-1 inactive GC had no transcriptional activity, in both transiently and stably transfected cells E and P demonstrated a dose-dependent transcriptional activity. This transcriptional potency of both inactive GC was effectively abolished by carbenoxolone, an 11-HSD-1 inhibitor, and was directly related to the concentration of transfected 11-HSD-1. We conclude that gene expression modulation by GC is under a decisive influence of target cell 11-HSD-1 that modulates the intracellular concentration of active GC. The intracrine mechanism is an under-appreciated aspect of GC activity that could be a potential target for future therapies aimed at modulating GC effects at the cellular level.
Molecular Endocrinology, Apr 1, 2004
Glucocorticoids exert their metabolic effect via their intracellular receptor, the glucocorticoid... more Glucocorticoids exert their metabolic effect via their intracellular receptor, the glucocorticoid receptor (GR). In a yeast two-hybrid screening, we found the chicken ovalbumin upstream promoter transcription factor II (COUP-TFII), an orphan nuclear receptor that plays important roles in glucose, cholesterol, and xenobiotic metabolism, as a partner of GR. In an in vitro glutathione-S-transferase pull-down assay, COUP-TFII interacted via its DNA-binding domain with the hinge regions of both GR␣ and its splicing variant GR, whereas COUP-TFII formed a complex with GR␣, but not with GR, in an in vivo chromatin immunoprecipitation and a regular immunoprecipitation assay. Accordingly, GR␣, but not GR, enhanced COUP-TFII-induced transactivation of the simple COUP-TFII-responsive 7␣-hydroxylase promoter through the transcriptional activity of its activation function-1 domain, whereas COUP-TFII repressed
The Journal of Steroid Biochemistry and Molecular Biology, Jun 1, 2003
Glucocorticoids have a broad array of life-sustaining functions and play an important role in the... more Glucocorticoids have a broad array of life-sustaining functions and play an important role in the therapy of many diseases. Thus, changes of tissue sensitivity to glucocorticoids may be associated with and influence the course and treatment of many pathologic states. Such tissue sensitivity changes may present on either side of an optimal range, respectively as glucocorticoid resistance or hypersensitivity, and may be generalized or tissue-specific. Familial/sporadic glucocorticoid resistance syndrome caused by inactivating mutations of the glucocorticoid receptor (GR) gene is a classic monogenic disorder associated with congenital, generalized glucocorticoid insensitivity, while several autoimmune, inflammatory and allergic diseases are often associated with resistance of the inflamed tissues to glucocorticoids. On the other hand, glucocorticoid hypersensitivity has been suggested in visceral obesity-related insulin resistance associated with components of the metabolic syndrome, and in the acquired immunodeficiency syndrome (AIDS) caused by human immunodeficiency virus type-1 (HIV-1) infection. Here, we have reviewed the molecular analyses of five familial and three sporadic cases of the familial/sporadic glucocorticoid resistance syndrome and discussed the possible contribution of newly identified molecules, such as HIV-1 accessory proteins Vpr and Tat, FLICE-associated huge protein (FLASH) and chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII), on the molecular regulation of GR activity, as well as their possible contribution to changes in tissue sensitivity to glucocorticoids in pathologic conditions. Published by Elsevier Science Ltd.
The Journal of Sexual Medicine, May 1, 2019
Methods: A large amount of patients affected by LUTS and treated with combination therapy underwe... more Methods: A large amount of patients affected by LUTS and treated with combination therapy underwent evaluation by ASEX questionnaire. Between them, 30 claimed for moderate effect of therapy on item 1, 2 and 3a (3 points, differently to 1 score referred before treatment start). Between inclusion criteria, there was no other drug treatment in the same period. In this particular population, we tried to treat them by tradamixin once a day for 60 days. We evaluated ASEX questionnaire at the end of treatment. We considered a significant improvement in analyzed items return to 1 score. Results: 18 claimed of improvement in 3a items (group A, 60%), then 12 referred an enduring score of 3 or an increase of only one point (group B, no worsening has been referred after treatment). Increase in item 1 and 2 has been referred in a large amount of patients (25, 83%). Improvement has been always reported contextually in item 1 and 2. Interestingly, no difference has been reported in two different group A and B (15/18 in group A, 10/12 in group B, no statistical difference). Conclusion: Tradamixin could have a role and could be evaluated in treatment of mild or moderate iatrogenic sexual symptoms referred by patients treated with combination therapy for LUTS. In particular, effect on erectile disfunction is significant independently to effect on libido. This aspect could be strongly improved by Tradamixin. More data are needed, increasing sample size. Policy of full disclosure: N. Arrighi collaborates as Consultant with Biohealth Italia Srl (IT)
The Journal of Sexual Medicine, May 1, 2019
Methods: A large amount of patients affected by LUTS and treated with combination therapy underwe... more Methods: A large amount of patients affected by LUTS and treated with combination therapy underwent evaluation by ASEX questionnaire. Between them, 30 claimed for moderate effect of therapy on item 1, 2 and 3a (3 points, differently to 1 score referred before treatment start). Between inclusion criteria, there was no other drug treatment in the same period. In this particular population, we tried to treat them by tradamixin once a day for 60 days. We evaluated ASEX questionnaire at the end of treatment. We considered a significant improvement in analyzed items return to 1 score. Results: 18 claimed of improvement in 3a items (group A, 60%), then 12 referred an enduring score of 3 or an increase of only one point (group B, no worsening has been referred after treatment). Increase in item 1 and 2 has been referred in a large amount of patients (25, 83%). Improvement has been always reported contextually in item 1 and 2. Interestingly, no difference has been reported in two different group A and B (15/18 in group A, 10/12 in group B, no statistical difference). Conclusion: Tradamixin could have a role and could be evaluated in treatment of mild or moderate iatrogenic sexual symptoms referred by patients treated with combination therapy for LUTS. In particular, effect on erectile disfunction is significant independently to effect on libido. This aspect could be strongly improved by Tradamixin. More data are needed, increasing sample size. Policy of full disclosure: N. Arrighi collaborates as Consultant with Biohealth Italia Srl (IT)
The Journal of Sexual Medicine, 2019
molecules related to GnRH release (kisspeptin, dynorphin). Concerning MetS components, PhyEx sign... more molecules related to GnRH release (kisspeptin, dynorphin). Concerning MetS components, PhyEx significantly reduced circulating cholesterol and visceral fat. In multivariate analyses, cholesterol levels resulted the main determinant for MetS-related alterations in penile, testicular and hypothalamic districts. Conclusion: In conclusion, our Results show that PhyEx may rescue erectile function, exert anti-inflammatory effects on hypothalamus and testis, and increase LH levels and T production, thus supporting a primary role for lifestyle modification to combat MetS-associated HG and ED.
The journal of nutrition, health & aging, 2017
Objectives: To investigate the association between adherence to the Mediterranean Diet (Med-Diet)... more Objectives: To investigate the association between adherence to the Mediterranean Diet (Med-Diet), cardiometabolic disorders and polypharmacy. Design: Cross-sectional study. Setting: Geriatrics outpatient clinic, Policlinico Umberto I, Sapienza University of Rome. Participants: 508 patients (219 male, 289 female) aged 50 to 89 who were evaluated for cardiovascular and metabolic disorders. Methods and Measurements: Patients underwent a comprehensive medical assessment including medical history and the use of medications. Adherence to Med-Diet was assessed using the validated Med-Diet 14-item questionnaire; for the analysis, patients were divided in high (≥8) and medium-low (<8) adherence. Polypharmacy was defined as taking ≥5 medications. Results: 476 patients completed the study. Mean age was 70.4 years; 58% female. Median Med-Diet score was 8 (6-9). Patients with medium-low adherence had higher body mass index (p=0.029) and higher prevalence of arterial hypertension (p<0.001), previous coronary (p=0.002) and cerebrovascular events (p=0.011), diabetes, (p<0.001) and dyslipidemia (p=0.001) compared to those at high adherence. Med-Diet score decreased with the number of cardiometabolic disorders (p<0.001). The prevalence of polypharmacy was 39%. Consumption of olive oil (p=0.005), vegetables, (p<0.001), wine (p=0.017), legumes (p=0.028), fish (p=0.046) and nuts (p=0.045) were all inversely associated with the overall number of medications. In a multivariable regression model, medium-low adherence to Med-Diet was independently associated to polypharmacy (O.R.:1.859; 95% CI 1.142 to 3.025; p=0.013), after adjusting for possible confounding factors. Conclusion: Med-Diet was inversely associated with cardiometabolic disorders and with polypharmacy, suggesting that improved Med-Diet adherence might potentially delay the onset of age-related health deterioration and reduce the need of multiple medications.
L-Carnitine is an essential nutrient with a major role in cellular energy production. There is ev... more L-Carnitine is an essential nutrient with a major role in cellular energy production. There is evidence that, at high doses, L-carnitine might mimic some of the biological activities of glucocorticoids, especially immunomodulation. To explore the molecular basis of this effect, we tested the influence of L-carnitine on glucocorticoid receptor-α (GRα) functions. Millimolar concentrations of L-carnitine, which were not cytotoxic in vitro, significantly reduced the whole cell binding of [ 3 H]dexamethasone to GRα by decreasing the affinity of this receptor for its steroid ligand. At the same concentrations, L-carnitine was able to trigger nuclear translocation of green fluorescent protein (GFP)-fused human GRα and transactivate the glucocorticoidresponsive mouse mammary tumor virus (MMTV) and TAT3 promoters in a dose-dependent fashion. This effect was solely dependent on the presence of glucocorticoid-responsive elements on the promoter and on the expression of functional GRα by the cell. Finally, similarly to glucocorticoids, L-carnitine suppressed tumor necrosis factor-α (TNFα) and interleukin-12 release by human primary monocytes stimulated with lipopolysaccharide ex vivo. Both GRα transactivation and cytokine suppression by L-carnitine were abrogated by the GRα-antagonist RU 486. Taken together, our results suggest that pharmacological doses of L-carnitine can activate GRα and, through this mechanism, regulate glucocorticoid-responsive genes, potentially sharing some of the biological and therapeutic properties of glucocorticoids. Key words: GR • immunity • cytokines-Carnitine (3-hydroxy-4-N,N,N-trimethylaminobutyrate) is a quaternary amine present in all animal species, as well as in several microorganisms and in some higher plants (1, 2). In humans, L-carnitine is synthesized only in small amounts by the liver, kidney, and brain (3, 4). Therefore, most of L-carnitine in the human body is derived from the diet, particularly red meat, fish, and dairy products (4). The main physiological role of L-carnitine is to drive short-, medium-, and long-chained free fatty acids through cell compartments as acyl-carnitine esters. Transfer of acyl groups in this L
Glucocorticoid (GC)-induced osteoporosis (GCOP) is the most common cause of osteoporosis in adult... more Glucocorticoid (GC)-induced osteoporosis (GCOP) is the most common cause of osteoporosis in adults aged 20-45 years as well as the most common cause of iatrogenic osteoporosis. GC excess, either endogenous or exogenous, induces bone loss in 30-50% of cases. Indeed, bone loss leading to fractures is perhaps the most incapacitating, sometimes partially irreversible, complication of GC therapy. Nevertheless, GCOP is often underdiagnosed and left untreated. The following article provides an update on the cellular and molecular mechanisms implicated in the pathophysiology of GC-induced bone loss, as well as some guidelines on diagnostic, preventive and therapeutic strategies for this medical condition, in an effort to promote a better knowledge and greater awareness of GCOP by both the patient and the physician.
L-Carnitine (3-hydroxy-4-N,N,N-trimethylaminobutyrate) is a conditionally essential nutrient with... more L-Carnitine (3-hydroxy-4-N,N,N-trimethylaminobutyrate) is a conditionally essential nutrient with a major role in cellular energy metabolism. It is available in the United States as both a prescription drug and an over-thecounter nutritional supplement. Accumulating evidence from both animal and human studies indicates that pharmacologic doses of L-carnitine (LCAR) have immunomodulatory effects resembling those of glucocorticoids (GC). On the other hand, in contrast to GC, which cause bone loss, LCAR seems to have positive effects on bone metabolism. To explore the molecular bases of this GClike activity of LCAR, we investigated its effects on glucocorticoid receptor (GR)-modulated cytokine release ex vivo, and on the transcriptional activity, intracellular trafficking, and binding of GR in vitro. At high noncytotoxic doses, LCAR (a) suppressed the lipopolysaccharide-stimulated release of tumor necrosis factor ␣ and interleukin-12 from primary human monocytes in a GC-like fashion, (b) stimulated the transcriptional activity of GR on the GCresponsive promoters, (c) triggered nuclear translocation of green fluorescent protein (GFP)-fused GR, and (d) reduced the whole cell binding of [ 3 H]dexamethasone to GR. These results suggest that LCAR is a "nutritional modulator" of the GR, by acting as an agonist-like compound. Since LCAR appears to have positive effects on bone metabolism, in contrast to GC, LCAR may share some of the therapeutic properties of GC, particularly on the immune system, but not their deleterious side effects on some of other organs/ tissues. Thus, LCAR is potentially a useful alternative compound of GC in particular therapeutic situations. The clinical and therapeutic implications of these findings, as well as a better understanding of their mechanisms, warrant further research.
The Journal of Clinical Endocrinology Metabolism, Jul 2, 2013
The β-isoform of human glucocorticoid receptor β (hGRβ) acts as a natural dominant negative inhib... more The β-isoform of human glucocorticoid receptor β (hGRβ) acts as a natural dominant negative inhibitor of hGRα-induced transactivation of glucocorticoid-responsive genes. We determined hGRβ ability to suppress hGRα transactivation that was induced by commonly used synthetic glucocorticoids. HepG2/C3A cells were transiently cotransfected with GR cDNA and a glucocorticoid-responsive promoter, luciferase (MMTV-luc). Transfected cells were incubated for 16 h with glucocorticoid and luciferase. For each compound, a dose-response curve was constructed, and half-maximal effective concentrations and maximal transcriptional activities were compared. hGRβ, at a 1:1 ratio to hGRα, differentially suppressed hGRα-induced maximal transcriptional activity stimulated by triamcinolone, dexamethasone, hydrocortisone, and betamethasone (by 96, 68, 62, and 49%, respectively) but not by methylprednisolone. The suppressive effect of hGRβ on hGRα-induced transactivation was stronger at lower concentrations of all tested glucocorticoids, whereas it was blunted at higher concentrations. We conclude that the potency of the dominant negative effect of hGRβ on hGRα-induced transactivation depends on both the type and the dose of the synthetic glucocorticoids in use. These results may provide helpful information concerning the selection of synthetic glucocorticoids for treatment of pathological conditions in which hGRβ modulates the sensitivity of tissues to glucocorticoids.
The Journal of Clinical Endocrinology and Metabolism, 2005
The β-isoform of human glucocorticoid receptor β (hGRβ) acts as a natural dominant negative inhib... more The β-isoform of human glucocorticoid receptor β (hGRβ) acts as a natural dominant negative inhibitor of hGRα-induced transactivation of glucocorticoid-responsive genes. We determined hGRβ ability to suppress hGRα transactivation that was induced by commonly used synthetic glucocorticoids. HepG2/C3A cells were transiently cotransfected with GR cDNA and a glucocorticoid-responsive promoter, luciferase (MMTV-luc). Transfected cells were incubated for 16 h with glucocorticoid and luciferase. For each compound, a dose-response curve was constructed, and half-maximal effective concentrations and maximal transcriptional activities were compared. hGRβ, at a 1:1 ratio to hGRα, differentially suppressed hGRα-induced maximal transcriptional activity stimulated by triamcinolone, dexamethasone, hydrocortisone, and betamethasone (by 96, 68, 62, and 49%, respectively) but not by methylprednisolone. The suppressive effect of hGRβ on hGRα-induced transactivation was stronger at lower concentrations of all tested glucocorticoids, whereas it was blunted at higher concentrations. We conclude that the potency of the dominant negative effect of hGRβ on hGRα-induced transactivation depends on both the type and the dose of the synthetic glucocorticoids in use. These results may provide helpful information concerning the selection of synthetic glucocorticoids for treatment of pathological conditions in which hGRβ modulates the sensitivity of tissues to glucocorticoids.
Uploads
Papers by Massimo U . De Martino