Cr(VI) promotes tight joint and oxidative damage by activating the Nrf2/ROS/Notch1 axis

This study aimed to investigate whether Cr(VI) induced tight joint and oxidative damage in the small intestine, as mediated by the nuclear factor erythroid 2-related factor 2 (Nrf2)/reactive oxygen species (ROS)/Notch1 axis crosstalk. Thirty-two ICR mice were obtained and subjected to Cr(VI) via intragastric administration daily for 5 days. Western blot (WB) analysis, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry (IHC) staining, and immunofluorescence (IF) staining were applied to detect small intestinal damage, Nrf2, Notch1, and respective downstream targets in this research. Results showed that Cr(VI) led to the tight joint and oxidative damage in the small intestine of mice. Nrf2 was stimulated, and Notch1 (Notch intracellular domain, NICD1) was activated to translocate into the nucleus and activate an antioxidant action. These findings were validated by WB analysis and IF staining. ROS levels increased as the Cr(VI) concentration increased. The colocalization analysis of Nrf2 and NICD1 implied that a crosstalk between Nrf2 and Notch1 existed. Therefore, this study indicated that the Nrf2/ROS/Notch1 axis crosstalk could aggravate the tight joint and oxidative damage in the small intestine after Cr(VI) treatment.     

Age-dependent differential crosstalk between alpha()-adrenergic and angiotensin receptors

BACKGROUND

Previous reports of crosstalk between alpha(1)-adrenergic receptors (α₁-AR) and angiotensin receptors (ATR) have pointed to the existence of physiological regulation between the sympathetic nervous system and the renin-angiotensin system at the receptor level. This regulation may have an important role in the control of blood pressure and may be modified in different cardiovascular pathologies. Aging is considered to be an independent cardiovascular risk factor. Nevertheless, neither the variation in physiological action or interaction of signal transduction between these two receptors as a result of aging has been established. To clarify these aspects, the interaction between α₁-AR and ATR was evaluated.

METHODS

The inotropic response of α₁-AR to agonists was assessed in the presence and absence of angiotensin II using the left atria of 3.5-, 12-, 18- and 24-month-old (young adult, middle aged, elderly and aged, respectively) male Wistar rats. In the four age groups of rat hearts, the activities of tyrosine kinase were measured when just the AT₁R subtype was activated, or when both α₁-AR and AT₁R were activated. The activities of cytosolic phospholipase A₂ and the levels of cyclic GMP were investigated when just the AT₂R subtype was activated, or when both α₁-AR and AT₂R were activated.

RESULTS

No effect was found on the cumulative concentration-response curve for phenylephrine when AT₁R was activated in 3.5- or 12-month-old rats. However, in 18- and 24-month-old rats, the maximum positive inotropic response and the negative logarithm of the effective 50% concentration increased markedly. No effect was found on the cumulative concentration-response curve induced by phenylephrine when AT₂R was activated. The activities of tyrosine kinase increased significantly in 3.5- and 12-month-old rats, but there was no difference in 18- and 24-month-old rats when α₁-AR and AT₁R were both activated compared with when just AT₁R was activated. Cytosolic phospholipase A₂ activity and cyclic GMP levels decreased significantly when both α₁-AR and AT₂R were activated compared with when just AT₂R was activated.

CONCLUSIONS

In the isolated left atria of elderly and aged rats, the activation of AT₁R enhanced the positive inotropic response induced by the activation of α₁-AR. The activation of AT₂R had no effect on the positive inotropic response induced by the activation of α₁-AR. The action of α₁-AR increased the signal transduction of AT₁R in young-adult and middle-aged rat hearts but had no effect in elderly and aged hearts. The action of α₁-AR had no effect on AT₂R signal transduction.     

Liver kidney crosstalk: Hepatorenal syndrome

The dying liver causes the suffocation of the kidneys, which is a simplified way of describing the pathophysiology of hepatorenal syndrome(HRS). HRS is characterized by reversible functional renal impairment due to reduced blood supply and glomerular filtration rate, secondary to increased vasodilators. Over the years, HRS has gained much attention and focus among hepatologists and nephrologists. HRS is a diagnosis of exclusion, and in some cases, it carries a poor prognosis. Different classifications have emerged to better understand, diagnose, and promptly treat this condition. This targeted review aims to provide substantial insight into the epidemiology, pathophysiology, diagnosis, and management of HRS, shed light on the various milestones of this condition, and add to our current understanding.     

Interrogating the interplay of angiogenesis and immunity in metastatic colorectal cancer

Colon cancer is the third most common malignancy and the fifth most frequent cause of death from neoplastic disease worldwide. At the time of diagnosis, more than 20% of patients already have metastatic disease. In the last 20 years, the natural course of the disease has changed due to major changes in the management of metastatic disease such as the advent of novel surgical and local therapy approaches as well as the introduction of novel chemotherapy drugs and targeted agents such as anti-epidermal growth factor receptor, anti-BRAF and antiangiogenics. Angiogenesis is a complex biological process of new vessel formation from existing ones and is an integral component of tumor progression supporting cancer cells to grow, proliferate and metastasize. Many molecules are involved in this proangiogenic process, such as vascular endothelial growth factor and its receptors on endothelial cells. A well-standardized methodology that is applied to assess angiogenesis in the tumor microenvironment is microvascular density by using immunohistochemistry with antibodies against endothelial CD31, CD34 and CD105 antigens. Even smaller molecules, such as the microRNAs, which are small non-coding RNAs, are being studied for their usefulness as surrogate biomarkers of angiogenesis and prognosis. In this review, we will discuss recent advances regarding the investigation of angiogenesis, the crosstalk between elements of the immune microenvironment and angiogenesis and how a disorganized tumor vessel network affects the trafficking of CD8+ T cells in the tumor bed. Furthermore, we will present recent data from clinical trials that combine antiangiogenic therapies with immune checkpoint inhibitors in colorectal cancer.     

激素性骨质疏松症发病机制的研究进展

激素性骨质疏松症是临床使用糖皮质激素后常见的副作用,对于激素性骨质疏松的发病机制,从信号通路的层面研究来看,糖皮质激素可以通过抑制骨形成的Wnt/β-catenin、BMPs等信号通路和促进骨吸收的OPG/RANKL/RANK等信号通路引起骨质疏松。近年来对自噬通路和非编码RNA等通路调节因子的研究发现其对激素性骨质疏松的形成有着重要的作用,而且部分通路间的交联反应也被证实是激素性骨质疏松发生的介导因素,这为激素性骨质疏松发病机制的研究提供了新的方向。但是,我们目前的研究层面很可能只是这个复杂的调控网络中的冰山一角,许多通路和调节因子的研究仍处于起步阶段,具体机制很多未完全阐明,仍需要更多的基础和临床实验去完善这个调控网络。本文拟对激素性骨质疏松的发病信号通路及相关通路调节因子研究现状进行综述,为该疾病的靶向治疗提供新的研究方向。     

Suppression of cell adhesion through specific integrin crosstalk on mixed peptide-polysaccharide matrices

Crosstalk of different integrins, which bind to distinct types of extracellular matrix proteins, promotes specific functions. This crosstalk has not been investigated in depth. Previously, we demonstrated that integrin-syndecan crosstalk accelerated cell adhesion. Here, we evaluated the crosstalk of two different integrins using mixed peptide-polysaccharide (chitosan or alginate) matrices. Two different integrin binding peptides, FIB1 (integrin αvβ3), EF1zz (integrin α2β1), and 531 (integrin α3β1), were mixed in various molar ratios (9:1, 4:1, 1:1) and conjugated on a polysaccharide matrix. The mixture of FIB1/EF1zz- and FIB1/531-polysaccharide matrices did not show any difference in human dermal fibroblast (HDF) adhesion against the mono polysaccharide matrices. Interestingly, the EF1zz/531-polysaccharide matrix (molar ratio = 1:4) exhibited significantly decreased cell adhesion, but other EF1zz/531-polysaccharide matrices did not show any difference. When we examined the signal transduction of the EF1zz/531(1:4), Y397 phosphorylation of FAK significantly decreased but Y514 phosphorylation of Src did not exhibit any differences. Further investigation revealed that this suppression was mediated by PI3K signaling through the activation of integrin, and PKA signaling modulated suppression of HDF attachment. These findings suggest that a mixed peptide-polysaccharide matrix using receptor specific ligands can regulate cellular functions through receptor-specific crosstalk and is a useful approach to understand receptor specific crosstalk.     

Crosstalk of vascular 5-HT1 receptors with other receptors: clinical implications

Blood vessels may either constrict or dilate in response to 5-HT, the response being dependent on the species, the vascular bed studied and the condition (healthy or diseased) of the subject studied. Vasoconstriction may be mediated by 5-HT_2A, but, in a variable proportion, also by 5-HT_1B receptors. The expression and function of 5-HT_1B receptors is likely to be increased in disease states such as hypertension, cerebrovascular disease and variant angina pectoris. Contractile responses mediated by 5-HT_1B receptors may be increased in blood vessels with damaged endothelium, but may also be augmented in the presence of low concentrations of other vasoconstrictors such as thromboxane A₂, endothelin-1, prostaglandin F_2α, angiotensin II, histamine, noradrenaline, phenylephrine or KCl. Such an augmentation, however, is not a generalized phenomenon, since it does not occur in all vascular beds and is not always induced by all substances mentioned above. Whereas the augmentation seems to depend on increased levels of the second messengers involved, the exact mechanism is not yet completely clear. The augmentation of 5-HT_1B receptor-mediated contractions may be of relevance in pathophysiological conditions such as variant angina and preeclampsia, where the development of 5-HT_1B receptors seems to be expedited. Further, augmentation of 5-HT_1B receptor-mediated contractions may be an important determinant in the case of chest symptoms experienced as a side effect of antimigraine drugs.