The Blockade of TACE-Dependent EGF Receptor Activation by Losartan-Erlotinib Combination Attenuates Renal Fibrosis Formation in 5/6-Nephrectomized Rats Under Vitamin D Deficiency

Abstract

Chronic kidney disease (CKD) has been considered a major public health issue. In addition to cardiovascular diseases and infections, hypovitaminosis D has been considered a non-traditional aggravating factor for CKD progression. Interstitial fibrosis is a hallmark of CKD strongly correlated with deterioration of renal function. Transforming growth factor β (TGF-β) is the major regulatory profibrotic cytokine in CKD. Many injurious stimuli converge on the TGF-β pathway, which has context-dependent pleiotropic effects and interacts with several related renal fibrosis formation (RFF) pathways. Epidermal growth factor receptor (EGFR) is critically involved in CKD progression, exerting a pathogenic role in RFF associated with TGF-β-related fibrogenesis. Among others, EGFR pathway can be activated by a disintegrin and a metalloproteinase known as tumor necrosis factor α-converting enzyme (TACE). Currently no effective therapy is available to completely arrest RFF and slow the progression of CKD. Therefore, we investigated the effects of a double treatment with losartan potassium (L), an AT1R antagonist, and the tyrosine kinase inhibitor erlotinib (E) on the alternative pathway of RFF related to TACE-dependent EGFR activation in 5/6-nephrectomized rats under vitamin D deficiency (D). During the 90-day protocol, male Wistar rats under D, were submitted to 5/6 nephrectomy (N) on day 30 and randomized into four groups: N+D, no treatment; N+D+L, received losartan (50 mg/kg/day); N+D+E, received erlotinib (6 mg/kg/day); N+D+L+E received losartan+erlotinib treatment. N+D+L+E data demonstrated that the double treatment with losartan+erlotinib not only blocked the TACE-dependent EGF receptor activation but also prevented the expression of TGF-β, protecting against RFF. This renoprotection by losartan+erlotinib was corroborated by a lower expression of ECM proteins and markers of phenotypic alteration as well as a lesser inflammatory cell infiltrate. Although erlotinib alone has been emerging as a renoprotective drug, its association with losartan should be considered as a potential therapeutic strategy on the modulation of RFF.

The association between obesity and vitamin D deficiency modifies the progression of kidney disease after ischemia/reperfusion injury

“…Corroborating our results, Decleves et al also observed increased renal and urinary expression of MCP-1 in mice fed a high-fat diet ( 35 ). In the present study, we also observed similar results concerning the renal expression of MCP-1, CD3+, and CD68+ cells in the VDD group, reinforcing the immunomodulatory effect of vitamin D ( 1 , 7 , 77 ). Of note, we found a higher renal expression of MCP-1, CD3+, and CD68+ cells in the HFDV group compared to all the other groups, demonstrating a synergistic effect of adipose tissue and vitamin D deficiency regarding the inflammatory process.…”

“…Inflammatory cells including macrophages and T cells play a key role in tissue homeostasis and immune responses, especially in the course of kidney diseases ( 7 , 77 ). Moreover, an exacerbated inflammatory response is usually associated with a growing RFF ( 7 , 77 ).…”

“…Inflammatory cells including macrophages and T cells play a key role in tissue homeostasis and immune responses, especially in the course of kidney diseases ( 7 , 77 ). Moreover, an exacerbated inflammatory response is usually associated with a growing RFF ( 7 , 77 ). This process involves several steps, including the stimulation of cell division and the production of chemokines to recruit cells to the site of injury ( 78 ).…”

“…Macrophage activation and function are heterogeneous and regulated by the microenvironment and stage of tissue injury, reflecting in different phenotypes ( 1 , 77 , 79 ). In general, macrophages are classified into two subtypes: (a) M1 macrophages, classically activated and considered pro-inflammatory due to their ability to produce and release pro-inflammatory cytokines, such as IL-1, IL-6, IL-12, IL- 23, and TNF-α; and (b) M2 macrophages, which are known to have anti-inflammatory and immunomodulatory functions ( 79 , 80 ).…”

“…Although not significant, we noticed a lower renal expression of CD206+ cells (M2 macrophages) in relation to the total amount of CD68+ cells in the HFDV group. It is reported that the balance between M1/M2 macrophages is related to the renal microenvironment and may influence the progression of renal disease ( 1 , 77 , 80 ). In previous studies, we demonstrated that vitamin D deficiency contributed to the extension of the active state of inflammation, reinforcing the role of vitamin D in the modulation of inflammatory cells ( 1 , 7 , 77 ).…”