Inhibition of calcium/calmodulin-dependent protein kinase II normalizes diabetes-induced abnormal vascular reactivity in the rat perfused mesenteric vascular bed

Targeting endothelial cells with golden spice curcumin: A promising therapy for cardiometabolic multimorbidity

Cardiometabolic multimorbidity (CMM) is an increasingly significant global public health concern. It encompasses the coexistence of multiple cardiometabolic diseases, including hypertension, stroke, heart disease, atherosclerosis, and T2DM. A crucial component to the development of CMM is the disruption of endothelial homeostasis. Therefore, therapies targeting endothelial cells through multi-targeted and multi-pathway approaches hold promise for preventing and treatment of CMM. Curcumin, a widely used dietary supplement derived from the golden spice Carcuma longa, has demonstrated remarkable potential in treatment of CMM through its interaction with endothelial cells. Numerous studies have identified various molecular targets of curcumin (such as NF-κB/PI3K/AKT, MAPK/NF-κB/IL-1β, HO-1, NOs, VEGF, ICAM-1 and ROS). These findings highlight the efficacy of curcumin as a therapeutic agent against CMM through the regulation of endothelial function. It is worth noting that there is a close relationship between the progression of CMM and endothelial damage, characterized by oxidative stress, inflammation, abnormal NO bioavailability and cell adhesion. This paper provides a comprehensive review of curcumin, including its availability, pharmacokinetics, pharmaceutics, and therapeutic application in treatment of CMM, as well as the challenges and future prospects for its clinical translation. In summary, curcumin shows promise as a potential treatment option for CMM, particularly due to its ability to target endothelial cells. It represents a novel and natural lead compound that may offer significant therapeutic benefits in the management of CMM.

Hydrogen sulfide donor GYY4137 attenuates vascular complications in mesenteric bed of streptozotocin-induced diabetic rats

Hydrogen sulfide (H₂S) has been reported to have beneficial effects in different pathological conditions.

OBJECTIVES

the effects of chronic treatment of diabetic rats with GYY4137 (slow releasing H₂S donor) or NaHS (fast releasing H₂S donor) on the reactivity of the mesenteric bed to vasoactive agonists and the changes in its downstream effectors, ERK1/2 and p38 MAP Kinase have been investigated. In addition, the levels of nitric oxide (NO) and H₂S in all groups were measured.

METHODS

diabetes was induced by a single intraperitoneal (ip) injection of streptozotocin (STZ; 55 mg/kg). Sprague Dawley (SD; n = 10-12/group) rats were randomly divided into six groups: control, STZ-induced diabetic rats, GYY4137-treated control, NaHS-treated control, GYY4137-treated diabetic, and NaHS-treated diabetic. After 28 days of treatment, rats were sacrificed and mesenteric beds were isolated for functional or biochemical studies. The vascular reactivity of the perfused mesenteric bed to norepinephrine, carbachol and sodium nitroprusside were determined by measurement of changes in perfusion pressure. Western blotting was performed to measure the protein expression of ERK1/2, p38, eNOS, and H₂S biosynthesizing enzymes cystathionine-β-synthase and cystathionine-γ-lyase. NO and H₂S levels were measured in all groups in isolated mesenteric tissues or plasma.

RESULTS

diabetes resulted in a significant increase in vasoconstrictor responses to norepinephrine (e.g., 129.6 ± 6.77 mmHg in diabetic vs 89.3 ± 8.48 mmHg in control at 10^-7 dose), and carbachol-induced vasodilation was significantly reduced in diabetic mesenteric bed (e.g., 68.9 ± 4.8 mmHg in diabetic vs 90.6 ± 2.2 mmHg in control at 10^-7 dose). Chronic treatment of the diabetic rats with GYY4137 resulted in a significant improvement in the response to norepinephrine (e.g., 86.66 ± 8.04 mmHg in GYY4137-treated diabetic vs 129.6 ± 6.77 mmHg in untreated diabetic at 10^-7 dose) or carbachol (e.g., 84.90 ± 2.48 mmHg in GYY4137-treated diabetic vs 68.9 ± 4.8 mmHg in untreated diabetic at 10^-7 dose). The biochemical studies showed a marked reduction of the protein expression of ERK and p38 and a significant upregulation of the expression of eNOS and H₂S synthesizing enzymes after chronic treatment with GYY4137. Plasma levels of NO and H₂S were significantly elevated after treatment with GYY4137. However, H₂S production in the mesenteric bed showed a marginal elevation in diabetic tissues compared to controls.

CONCLUSION

the results indicate that GYY4137 may be a novel therapeutic tool to prevent diabetes-associated vascular dysfunction.

Curcumin in Retinal Diseases: A Comprehensive Review from Bench to Bedside

Recent evidence in basic science is leading to a growing interest in the possible role of curcumin in treating retinal diseases. Curcumin has been demonstrated to be able to modulate gene transcription and reduce ganglion cell apoptosis, downgrade VEGF, modulate glucose levels and decrease vascular dysfunction. So far, the use of curcumin has been limited by poor bioavailability; to overcome this issue, different types of carriers have been used. Multiple recent studies disclosed the efficacy of using curcumin in treating different retinal conditions. The aim of this review is to comprehensively review and discuss the role of curcumin in retinal diseases from bench to bedside.

Gut microbiota dependent trimethylamine N-oxide aggravates angiotensin II-induced hypertension

Gut microbiota produce Trimethylamine N-oxide (TMAO) by metabolizing dietary phosphatidylcholine, choline, l-carnitine and betaine. TMAO is implicated in the pathogenesis of chronic kidney disease (CKD), diabetes, obesity and atherosclerosis. We test, whether TMAO augments angiotensin II (Ang II)-induced vasoconstriction and hence promotes Ang II-induced hypertension. Plasma TMAO levels were indeed elevated in hypertensive patients, thus the potential pathways by which TMAO mediates these effects were explored. Ang II (400 ng/kg⁻¹min⁻¹) was chronically infused for 14 days via osmotic minipumps in C57Bl/6 mice. TMAO (1%) or antibiotics were given via drinking water. Vasoconstriction of renal afferent arterioles and mesenteric arteries were assessed by microperfusion and wire myograph, respectively. In Ang II-induced hypertensive mice, TMAO elevated systolic blood pressure and caused vasoconstriction, which was alleviated by antibiotics. TMAO enhanced the Ang II-induced acute pressor responses (12.2 ± 1.9 versus 20.6 ± 1.4 mmHg; P < 0.05) and vasoconstriction (32.3 ± 2.6 versus 55.9 ± 7.0%, P < 0.001). Ang II-induced intracellular Ca²⁺ release in afferent arterioles (147 ± 7 versus 234 ± 26%; P < 0.001) and mouse vascular smooth muscle cells (VSMC, 123 ± 3 versus 157 ± 9%; P < 0.001) increased by TMAO treatment. Preincubation of VSMC with TMAO activated the PERK/ROS/CaMKII/PLCβ3 pathway. Pharmacological inhibition of PERK, ROS, CaMKII and PLCβ3 impaired the effect of TMAO on Ca²⁺ release. Thus, TMAO facilitates Ang II-induced vasoconstriction, thereby promoting Ang II-induced hypertension, which involves the PERK/ROS/CaMKII/PLCβ3 axis.

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Orally administered TMAO aggravates Ang II-induced hypertension. Antibiotics alleviate Ang II-induced hypertension by reducing TMAO generation.

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High concentrations of TMAO constrict afferent arterioles and mesenteric arteries and increase blood pressure.

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Low concentrations of TMAO enhance Ang II-induced vasoconstriction and acute pressor response via activating PERK/ROS/CaMKII/PLCβ3/Ca²⁺ pathway.

Curcumin Inhibits Neuronal Loss in the Retina and Elevates Ca²⁺/Calmodulin-Dependent Protein Kinase II Activity in Diabetic Rats

PURPOSE

To determine whether curcumin offers neuroprotection to minimize the apoptosis of neural cells in the retina of diabetic rats.

METHODS

Streptozotocin (STZ)-induced diabetic rats and control rats were used in this study. A subgroup of STZ-induced diabetic rats were treated with curcumin for 12 weeks. Retinal histology, apoptosis of neural cells in the retina, electroretinograms, and retinal glutamate content were evaluated after 12 weeks. Retinal levels of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII), phospho-CaMKII (p-CaMKII), and cleaved caspase-3 were determined by Western blot analysis.

RESULTS

The amplitudes a-wave, b-wave, and oscillatory potential were reduced by diabetes, but curcumin treatment suppressed this reduction of amplitudes. Curcumin also prevented cell loss from the outer nuclear, inner nuclear, and ganglion cell layers. Apoptosis of retinal neurons was detected in diabetic rats. The concentration of glutamate in the retina was higher in diabetic rats, but was significantly reduced in the curcumin-treated group. Furthermore, p-CaMKII and cleaved caspase-3 expression were upregulated in the diabetic retina, but reduced in curcumin-treated rats.

CONCLUSIONS

Curcumin attenuated diabetes-induced apoptosis in retinal neurons by reducing the glutamate level and downregulating CaMKII. Thus, curcumin might be used to prevent neuronal damage in the retina of patients with diabetes mellitus.

Activation of M3 cholinoceptors attenuates vascular injury after ischaemia/reperfusion by inhibiting the Ca2+/calmodulin-dependent protein kinase II pathway

BACKGROUND AND PURPOSE

The activation of M3 cholinoceptors (M3 receptors) by choline reduces cardiovascular risk, but it is unclear whether these receptors can regulate ischaemia/reperfusion (I/R)-induced vascular injury. Thus, the primary goal of the present study was to explore the effects of choline on the function of mesenteric arteries following I/R, with a major focus on Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) regulation.

EXPERIMENTAL APPROACH

Rats were given choline (10 mg · kg(-1), i.v.) and then the superior mesenteric artery was occluded for 60 min (ischaemia), followed by 90 min of reperfusion. The M3 receptor antagonist, 4-diphenylacetoxy-N-methylpiperidine methiodide (4-DAMP), was injected (0.12 μg · kg(-1), i.v.) 5 min prior to choline treatment. Vascular function was examined in rings of mesenteric arteries isolated after the reperfusion procedure. Vascular superoxide anion production, CaMKII and the levels of Ca(2+)-cycling proteins were also assessed.

KEY RESULTS

Choline treatment attenuated I/R-induced vascular dysfunction, blocked elevations in the levels of reactive oxygen species (ROS) and decreased the up-regulated expression of oxidised CaMKII and phosphorylated CaMKII. In addition, choline reversed the abnormal expression of Ca(2+)-cycling proteins, including Na(+)Ca(2+) exchanger, inositol 1,4,5-trisphosphate receptor, sarcoplasmic reticulum Ca(2+)-ATPase and phospholamban. All of these cholinergic effects of choline were abolished by 4-DAMP.

CONCLUSIONS AND IMPLICATIONS

Our data suggest that inhibition of the ROS-mediated CaMKII pathway and modulation of Ca(2+)-cycling proteins may be novel mechanisms underlying choline-induced vascular protection. These results represent a significant addition to the understanding of the pharmacological roles of M3 receptors in the vasculature, providing a new therapeutic strategy for I/R-induced vascular injury.

Biana: a software framework for compiling biological interactions and analyzing networks

Background

The analysis and usage of biological data is hindered by the spread of information across multiple repositories and the difficulties posed by different nomenclature systems and storage formats. In particular, there is an important need for data unification in the study and use of protein-protein interactions. Without good integration strategies, it is difficult to analyze the whole set of available data and its properties.

Results

We introduce BIANA (Biologic Interactions and Network Analysis), a tool for biological information integration and network management. BIANA is a Python framework designed to achieve two major goals: i) the integration of multiple sources of biological information, including biological entities and their relationships, and ii) the management of biological information as a network where entities are nodes and relationships are edges. Moreover, BIANA uses properties of proteins and genes to infer latent biomolecular relationships by transferring edges to entities sharing similar properties. BIANA is also provided as a plugin for Cytoscape, which allows users to visualize and interactively manage the data. A web interface to BIANA providing basic functionalities is also available. The software can be downloaded under GNU GPL license from http://sbi.imim.es/web/BIANA.php.

Conclusions

BIANA's approach to data unification solves many of the nomenclature issues common to systems dealing with biological data. BIANA can easily be extended to handle new specific data repositories and new specific data types. The unification protocol allows BIANA to be a flexible tool suitable for different user requirements: non-expert users can use a suggested unification protocol while expert users can define their own specific unification rules.

Role of epidermal growth factor receptor (EGFR) in corneal remodelling in diabetes

PURPOSE

This study examined the role of epidermal growth factor receptor (EGFR) signalling on the organization and remodelling of collagen fibrils (CFs) and proteoglycans (PGs) in the stroma of diabetic rat cornea.

METHODS

Diabetes was induced in female Wistar rats (n = 5) by streptozotocin (STZ) injection (55 mg/kg). Treatment with a selective inhibitor of EGFR tyrosine kinase, AG1478, was started on the same day as the induction of diabetes and administered every other day for 4 weeks. Corneas were fixed in 4% paraformaldehyde at 4 degrees to allow for analysis of CF diameters and in 2.5% glutaraldehyde in sodium acetate buffer containing cuprolinic blue to enable the study of PG distribution. AnalySIS soft imaging software was used to analyse CFs and PGs.

RESULTS

Epithelial thickness, and median diameter and area fraction of CF in corneal stroma were decreased in diabetic rat cornea compared with normal cornea (p < 0.001), whereas the median PG area and area fractions were significantly increased (p < 0.001). Treatment with AG1478, although it had no action on normal cornea, prevented these diameter and area fraction changes in CFs and PGs. The cornea of AG1478-treated diabetic rats showed a slight increase in CF diameter and area fraction and a decreased number density.

CONCLUSIONS

These data show that the distribution of corneal stroma CFs and PGs was altered after 4 weeks of diabetes and that, furthermore, treatment with an EGFR signalling inhibitor normalized these abnormalities. The data suggest that EGFR plays an important role in the development of diabetes-induced corneal remodelling.

Early inhibition of EGFR signaling prevents diabetes-induced up-regulation of multiple gene pathways in the mesenteric vasculature

Diabetes mellitus is associated with vascular complications including an impairment of vascular function and alterations in the reactivity of blood vessels to vasoactive hormones. However, the signaling mechanisms leading to vascular dysfunction in diabetes are not fully understood. This microarray-based study was designed to identify differential gene expression between the normal and diabetic mesenteric vasculature and to investigate the effect of inhibiting epidermal growth factor receptor (EGFR) signaling on global gene expression in the mesenteric bed of streptozotocin (STZ)-induced diabetic rats. Transcriptome analysis was performed in triplicate using oligonucleotide microarrays housing 10,000 rat genes on the mesenteric bed of normal, diabetic, and diabetic rats treated with AG1478, a selective inhibitor of EGFR. Four weeks of diabetes led to a profound alteration in gene expression within the mesenteric bed with 1167 of the 3074 annotated genes being up-regulated and 141 genes down-regulated by at least 2-fold. The up-regulated gene ontologies included receptor tyrosine kinases, G-protein coupled receptors and ion channel activity. In particular, significant overexpressions of colipase, phospholipase A2, carboxypeptidases, and receptor tyrosine kinases such as EGFR, erbB2 and fibroblast growth factor receptor were observed in diabetes mesenteric vasculature. A 4-week intraperitoneal treatment of diabetic animals with AG1478 (1.2 mg/kg/alt diem) beginning on the same day as STZ injection prevented up-regulation of the majority (approximately 95%) of the genes associated with STZ diabetes including those apparently "unrelated" to the known EGFR pathway without correction of hyperglycemia. These results suggest that activation of EGFR signaling is a key initiating step that leads to induction of multiple signaling pathways in the development of diabetes-induced vascular dysfunction. Thus, therapeutic targeting of EGFR may represent a novel strategy for the prevention and/or treatment of vascular dysfunction in diabetes.

Role of 20-hydroxyeicosatetraenoic acid in altering vascular reactivity in diabetes

1 This study examined the role of 20-hydroxyeicosatetraenoic (20-HETE) in altering vascular function in streptozotocin (STZ)-induced diabetic rats. 2 The expression of CYP4A protein and the formation of 20-HETE were elevated in the kidney, but not in the renal or mesenteric vasculature, of diabetic animals. The vasoconstrictor responses to norepinephrine (NE), endothelin-1 (ET-1), and angiotensin II (Ang II) were significantly enhanced in the isolated perfused mesenteric vascular bed and renal artery segments of diabetic rats. Chronic treatment of the diabetic rats with 1-aminobenzotriazole (ABT, 50 mg kg(-1) alt(-1) diem) or N-hydroxy-N'-(4-butyl-2-methylphenyl) formamidine (HET0016, 2.5 mg kg(-1) day(-1)) attenuated the responses to these vasoconstrictors in both vascular beds. 3 The synthesis of 20-HETE in renal microsomes was reduced by >80% confirming that the doses of ABT and HET0016 were sufficient to achieve system blockade. Addition of HET0016 (1 microM) in vitro also normalized the enhanced vascular responsiveness of renal and mesenteric vessels obtained from diabetic animals to NE and inhibited the formation of 20-HETE by >90% while having no effect on the formation of epoxides. Vasodilator responses to carbachol and histamine were reduced in the mesenteric vasculature, but not in renal arteries, of diabetic rats. Treatment of the diabetic animals with HET0016 improved vasodilator responses in both vascular beds. Vascular sensitivity to exogenous 20-HETE was elevated in the mesenteric bed of diabetic animals compared to controls. 4 These results suggest that 20-HETE contributes to the elevation in vascular reactivity in diabetic animals. This effect is not due to increased vascular expression of CYP4A but may be related to either enhanced agonist-induced release of substrate (arachidonic acid) by the CaMKII/Ras-GTPase system and/or elevated vascular responsiveness to 20-HETE by the CaMKII/Ras-GTPase system and/or elevated vascular responsiveness to 20-HETE.

Phosphoinositide 3-kinase contributes to diabetes-induced abnormal vascular reactivity in rat perfused mesenteric bed

Phosphatidylinositol 3-kinase (PI3K) is a signaling enzyme that plays key roles in vascular growth, proliferation, and cellular apoptosis and is implicated in modulating vascular smooth muscle contractility. The aim of this study was to determine whether PI3K contributes to development of diabetes-induced abnormal vascular reactivity to selected vasoactive agonists. The effect of 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002), a selective PI3K inhibitor, on isolated perfused mesenteric vascular bed from streptozotocin (STZ)-diabetic rats was investigated. Changes in perfusion pressure, which reflected peripheral resistance, were measured using isolated perfused mesenteric vascular beds. Our results showed that STZ treatment produced an increase in the vasoconstrictor response to norepinephrine (NE), angiotensin II (Ang II) and endothelin-1 (ET-1), and an attenuated vasodilator response to carbachol and histamine in the isolated perfused mesenteric vascular bed from STZ-diabetic animals. Chronic inhibition of PI3K with LY294002 resulted in prevention of diabetes-induced abnormal vascular reactivity to the vasoactive agonists. However, the high blood glucose levels were not normalized. Results of this study indicate that selective inhibition of PI3K can attenuate the development of diabetes-induced abnormal vascular responsiveness in the isolated perfused mesenteric vascular bed.

Signal transduction through Ras-GTPase and Ca2+/ calmodulin-dependent protein kinase II contributes to development of diabetes-induced renal vascular dysfunction

This study examined the role of Ca2+/calmodulin-dependent protein kinase II (CaMKII) and Ras-GTPase in the development of abnormal reactivity to vasoactive agents in the renal artery of diabetic rats. The vasoconstrictor response induced by norepinephrine (NE), endothelin-1 (ET-1) or angiotensin II (Ang II) was significantly increased whereas vasodilator response to carbachol, histamine or sodium nitroprusside (SNP) was not altered in the renal artery segments of the streptozotocin (STZ)-diabetic rats. Chronic intraperitoneal administration of KN-93 (5 mg/kg/ alt diem), an inhibitor of CaMKII or FPTIII (1.5 mg/kg/ alt diem), an inhibitor of Ras-GTPase, produced significant normalization of the altered agonist-induced vasoconstrictor responses without affecting blood glucose levels. All the inhibitors were administered for four weeks starting from day one of diabetes induction. Inhibition of Ras-GTPase or CaMKII did not affect the agonist-induced vasoconstrictor and vasodilator responses in the non-diabetic control animals. These data suggest that inhibition of signal transduction involving CaMKII and Ras-GTPase can prevent development of diabetes-induced abnormal vascular reactivity in the renal artery.

Phosphoinositide 3-kinase mediated signalling contributes to development of diabetes-induced abnormal vascular reactivity of rat carotid artery

Diabetes mellitus is associated with vascular complications, including an impairment of vascular function and alterations in the reactivity of blood vessels to vasoactive agents. Phosphatidylinositol 3-kinase (PI3K) is a signalling enzyme that plays key roles in vascular growth, proliferation and cellular apoptosis and is implicated in modulating vascular smooth muscle contractility. The aim of this study was to determine whether PI3K plays a role in development of diabetes-induced altered vascular reactivity to selected vasoconstrictors and vasodilators. The effect of 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one (LY294002), a selective PI3K inhibitor, on isolated segments of carotid arteries from streptozotocin (STZ)-diabetic rats was investigated. Ring segments of the isolated carotid arteries were mounted in organ baths to measure changes in isometric tension. Our results showed that STZ treatment produced an increase in the vasoconstrictor response to norepinephrine (NE), angiotensin II (Ang II) and endothelin-1 (ET-1) and an attenuated vasodilator response to carbachol and histamine in the isolated carotid arteries from STZ-diabetic animals. Diabetes-induced impaired vascular responsiveness to the vasoactive agonists was prevented by chronic inhibition of PI3K by LY294002 even though blood glucose levels remained high. This is the first study to show that selective inhibition of PI3K can attenuate the development of diabetes-induced abnormal vascular reactivity in the isolated carotid arteries of diabetic rats.

Effect of des-aspartate-angiotensin I on the actions of angiotensin II in the isolated renal and mesenteric vasculature of hypertensive and STZ-induced diabetic rats

The present study investigated the action of des-aspartate-angiotensin I (DAA-I) on the pressor action of angiotensin II in the renal and mesenteric vasculature of WKY, SHR and streptozotocin (STZ)-induced diabetic rats. Angiotensin II-induced a dose-dependent pressor response in the renal vasculature. Compared to the WKY, the pressor response was enhanced in the SHR and reduced in the STZ-induced diabetic rat. DAA-I attenuated the angiotensin II pressor action in renal vasculature of WKY and SHR. The attenuation was observed for DAA-I concentration as low as 10(-18) M and was more prominent in SHR. However, the ability of DAA-I to reduce angiotensin II response was lost in the STZ-induced diabetic kidney. Instead, enhancement of angiotensin II pressor response was seen at the lower doses of the octapeptide. The effect of DAA-I was not inhibited by PD123319, an AT2 receptor antagonist, and indomethacin, a cyclo-oxygenase inhibitor in both WKY and SHR, indicating that its action was not mediated by angiotensin AT2 receptor and prostaglandins. The pressor responses to angiotensin II in mesenteric vascular bed were also dose-dependent but smaller in magnitude compared to the renal vasculature. The responses were significantly smaller in SHR but no significant difference was observed between STZ-induced diabetic and WKY rat. Similarly, PD123319 and indomethacin had no effect on the action of DAA-I. The findings reiterate a regulatory role for DAA-I in vascular bed of the kidney and mesentery. By being active at circulating level, DAA-I subserves a physiological role. This function appears to be present in animals with diseased state of hypertension and diabetes. It is likely that DAA-I functions are modified to accommodate the ongoing vascular remodeling.