Dihydrotestosterone promotes vascular cell adhesion molecule-1 expression in male human endothelial cells via a nuclear factor-kappaB-dependent pathway.
Death AK, McGrath KC, Sader MA, Nakhla S, Jessup W, Handelsman DJ, Celermajer DS.
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Abstract
There exists a striking gender difference in atherosclerotic vascular disease.
For decades, estrogen was considered atheroprotective; however, an alternative is that androgen exposure in early life may predispose men to earlier atherosclerosis.
We recently demonstrated that the potent androgen, dihydrotestosterone (DHT), enhanced the binding of monocytes to the endothelium, a key early event in atherosclerosis, via increased expression of vascular cell adhesion molecule-1 (VCAM-1).
We now show that DHT mediates its effects on VCAM-1 expression at the promoter level through a novel androgen receptor (AR)/nuclear factor-kappaB (NF-kappaB) mechanism.
Human umbilical vein endothelial cells were exposed to 4-400 nm DHT. DHT increased VCAM-1 mRNA in a dose- and time-dependent manner. The DHT effect could be blocked by the AR antagonist, hydroxyflutamide.
DHT increased VCAM-1 promoter activity via NF-kappaB activation without affecting VCAM-1 mRNA stability.
Using 5' deletion analysis, it was determined that the NF-kappaB sites within the VCAM-1 promoter region were responsible for the DHT-mediated increase in VCAM-1 expression;
however, coimmunoprecipitation studies suggested there is no direct interaction between AR and NF-kappaB.
Instead, DHT treatment decreased the level of the NF-kappaB inhibitory protein.
DHT did not affect VCAM-1 protein expression and monocyte adhesion when female endothelial cells were tested.
AR expression was higher in male, relative to female, endothelial cells, associated with increased VCAM-1 levels.
These findings highlight a novel AR/NF-kappaB mediated mechanism for VCAM-1 expression and monocyte adhesion operating in male endothelial cells that may represent an important unrecognized mechanism for the male predisposition to atherosclerosis.
Αν η παραπάνω μελέτη δεν είναι αέρας κοπανιστός, πιστεύω ότι περιγράφει απόλυτα το ότι η DHT, δεν είναι η αιτία της Α.Α.
Αντίθετα τονίζει τα εξής.
1. Τα οιστρογόνα προστατεύουν τα γυναικεία ενδοθηλιακά κύτταρα από την αθηροσκλήρωση.
2. Η έκθεση των ανδρών κατά την εφηβεία στα ανδρογόνα πυροδοτεί την διαδικασία αθηροσκλήρωσης.
3. Η όλη ζημιά που μπορεί να κάνει η DHT, δεν έχει καμία μα καμία σχέση με τους θύλακες, άρα για άλλη μια φορά η θεωρία ευαίσθητων θυλάκων στα ανδρογόνα μοιάζει γελοία, αλλά με το ότι υποκινεί - αυξάνει την έκφραση του μορίου προσκόλλησης αγγειακού κυττάρου - 1 (Vcam-1)
Αυτό το καταφέρνει μέσω του ανδρ.υποδοχέα στο ενδοθήλιο.
4. Ο άμεσος υπεύθυνος και η πραγματική αιτία του προβλήματος, φαίνεται να είναι η πρωτεΐνη Nf-Kappa B η οποία δεν έχει καμία επίδραση στους ανδρ.υποδοχείς.
5. Στα υγιεί γυναικεία ενδοθηλιακά κύτταρα, η dht δεν είχε καμία αρνητική επίδραση όσον αφορά τον παράγοντα vcam-1
Άρα, χωρίς την ενεργοποίηση της nf kb, στα ενδοθηλιακά κύτταρα, η dht δεν θα είχε καμία επίδραση σε εμάς, όπως και στους ανθρώπους που δεν έχουν θέμα φαλάκρας.
Μια βασική αιτία της ενεργοποίησης αυτής, είναι τα ελεύθερα λιπαρά οξέα (κορεσμένα κυρίως) και η αντίσταση στην ινσουλίνη, με το ένα να συμπληρώνει το άλλο.
Fatty acid-induced NF-kappaB activation and insulin resistance in skeletal muscle are chain length dependent.
Hommelberg PP, Plat J, Langen RC, Schols AM, Mensink RP.
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Abstract
The saturated fatty acid (SFA) palmitate induces insulin resistance in cultured skeletal muscle cells, which may be related to NF-kappaB activation.
The aim of this study was to evaluate whether other SFAs also exert these effects on skeletal muscle and whether these relate to chain length. Therefore, we incubated L6 and C(2)C(12) skeletal muscle cells with four different fatty acids, caprylate (C8:0), laurate (C12:0), palmitate (C16:0), and stearate (C18:0), to study effects on GLUT4 translocation, deoxyglucose uptake, and NF-kappaB activation.
Incubation of L6 cells with the long-chain FAs C16:0 and C18:0 reduced insulin-stimulated GLUT4 translocation and deoxyglucose uptake, whereas L6 cells incubated with the medium-chain FAs C8:0 and C12:0 remained insulin sensitive. Besides increasing NF-kappaB DNA binding activity in both L6 and C(2)C(12) cells, C16:0 also induced NF-kappaB transcriptional activity. C18:0 showed comparable effects, whereas the SFAs with shorter chain lengths were not able to elevate NF-kappaB transcriptional activity.
Collectively, these results demonstrate that SFA-induced NF-kappaB activation coincides with insulin resistance and depends on FA chain length.
Αν αντί να ασχολούμασταν όλοι με την dht και τις φιναστερίδες, ψαχνόμασταν για κάτι ανάλογο όπως το παρακάτω, θα είχαμε πιστεύω καλύτερη τύχη.
Celastrol, an NF-κB inhibitor, improves insulin resistance and attenuates renal injury in db/db mice.
Kim JE, Lee MH, Nam DH, Song HK, Kang YS, Lee JE, Kim HW, Cha JJ, Hyun YY, Han SY, Han KH, Han JY, Cha DR.
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Abstract
The NF-κB pathway plays an important role in chronic inflammatory and autoimmune diseases.
Recently, NF-κB has also been suggested as an important mechanism linking obesity, inflammation, and metabolic disorders.
However, there is no current evidence regarding the mechanism of action of NF-κB inhibition in insulin resistance and diabetic nephropathy in type 2 diabetic animal models.
We investigated the effects of the NF-κB inhibitor celastrol in db/db mice. The treatment with celastrol for 2 months significantly lowered fasting plasma glucose (FPG), HbA1C and homeostasis model assessment index (HOMA-IR) levels.
Celastrol also exhibited significant decreases in body weight, kidney/body weight and adiposity.
Celastrol reduced insulin resistance and lipid abnormalities and led to higher plasma adiponectin levels.
Celastrol treatment also significantly mitigated lipid accumulation and oxidative stress in organs including the kidney, liver and adipose tissue. The treated group also exhibited significantly lower creatinine levels and urinary albumin excretion was markedly reduced.
Celastrol treatment significantly lowered mesangial expansion and suppressed type IV collagen, PAI-1 and TGFβ1 expressions in renal tissues.
Celastrol also improved abnormal lipid metabolism, oxidative stress and proinflammatory cytokine activity in the kidney. In cultured podocytes, celastrol treatment abolished saturated fatty acid-induced proinflammatory cytokine synthesis.
Taken together, celastrol treatment not only improved insulin resistance, glycemic control and oxidative stress, but also improved renal functional and structural changes through both metabolic and anti-inflammatory effects in the kidney.
These results suggest that targeted therapy for NF-κB may be a useful new therapeutic approach for the management of type II diabetes and diabetic nephropathy.