Views: 2 Author: Wei Tan, Yunyan Wang, Hongmei Dai, Junhui Deng, Zhifen Wu, Lirong Lin, and Jurong Yang Publish Time: 2022-10-11 Origin: Front. Pharmacol., 08 July 2022 Sec. Renal Pharmacology https://doi.org/10.3389/fphar.2022.932172
Renal fibrosis (RF) is a common outcome of various chronic kidney disease (CKD) processes and is the main pathological change in the progression of CKD to end-stage renal disease. It includes glomerulosclerosis (GS), renal interstitial fibrosis (RIF), as well as arteriosclerosis and perivascular fibrosis, and is histopathologically characterized by excessive deposition of extracellular matrix (ECM), tubular atrophy, inflammatory cell infiltration, and Loss of peritubular microvessels. Subsequent organ structural and functional impairment occurs, with scarring and hardening of the renal parenchyma. Cells involved in this event include tubular epithelial cells (TECs), endothelial cells (ECs), fibroblasts, pericytes, macrophages, and mast cells. Furthermore, cellular and molecular events such as inflammatory injury, oxidative stress, apoptosis, fibroblast activation, and epithelial-mesenchymal transition (EMT) are closely related to renal fibrosis. Despite significant progress in preclinical research on RF mechanisms and their therapeutic targets, clinical practice has yet to be proven, and effective treatments specifically targeting RF are still lacking.
Cordyceps is a fungus that parasitizes insect larvae. It has been used as a medicine in China, Japan and other Asian countries for centuries. It has several species, including Cordyceps sinensis, Cordyceps militaris, and Cordyceps sinensis. Cordyceps has a variety of medicinal properties or biologically active compounds, including nucleosides, polysaccharides, cyclic depsipeptides, sterols, alkaloids, and phenolic substances, which have immunomodulatory, antitumor, anti-inflammatory, antioxidant, and renal protection effects. Cordyceps has shown potential as a routine drug adjunct to lowering serum creatinine (Scr), increasing creatinine clearance, reducing proteinuria, and alleviating CKD-related complications. Based on the network pharmacology tool used to study the molecular mechanism of Cordyceps in treating diabetic nephropathy (DN), 7 active components were screened from Cordyceps, 293 putative target genes were identified, and 85 overlapping targets matching DN and potential therapeutic targets such as tumor necrosis factor (TNF), mitogen-activated protein kinase 1, epidermal growth factor receptor (EGFR), angiotensin-converting enzyme, and Caspase-9. Cordyceps participates in inflammatory response, apoptosis, oxidative stress, insulin resistance and other biological processes through these pathways.
1. Mechanisms of Cordyceps and related products against renal fibrosis
Cordyceps anti-inflammatory
Inflammation is the initiator of renal fibrosis, and persistent chronic inflammation is considered a hallmark feature of CKD. In response to causative factors, damaged renal tubular epithelial cell TECs recruit inflammatory cells to the renal interstitial region, and these inflammatory cells then produce large amounts of proinflammatory and profibrotic cytokines. Various active ingredients in Cordyceps have anti-inflammatory properties. Cordyceps extract alleviates renal histological changes, reduces serum creatinine Scr and blood urea nitrogen (BUN) levels, and reduces inflammatory factors in acute kidney injury (AKI), including renal ischemia/reperfusion injury and cisplatin-induced AKI . Cordyceps sinensis, Cordyceps sinensis polysaccharide (CCP) or N 6 -(2-hydroxyethyl) adenosine in renal fibrosis associated with streptozotocin (STZ) or alloxan monohydrate-induced diabetic nephropathy The active component of (HEA) is effective in reducing the expression of pro-inflammatory cell factors TNF-α, IL-1β and IL-6 in serum and kidneys and the expression of interstitial fibrosis-related proteins α-SMA and collagen I. In vitro, CCP also reduced lipopolysaccharide-induced proinflammatory factor release and TGF-β-induced fibroblast activation. Unilateral ureteral obstruction (UUO) is a classic model of RF, and Cordyceps extract HEA can reduce fibrosis-related proteins TGF-β1, α-SMA, collagen type I and fibronectin, and inflammatory factors in renal tissue 14 days after UUO TNF-α, IL-6 and IL-1β. The study initially explored the effect of HEA on inflammatory cells and found that HEA blocked the accumulation of M1 macrophages and induced the accumulation of M2 macrophages in the kidney, which was reflected in the positive detection of F4/80 antigen. The role of M2 macrophages in fibrosis is controversial, but the M1/M2 macrophage ratio is an important stage in the development of renal interstitial fibrosis.
Cordyceps reduces oxidative stress
The kidney is a highly metabolically active organ, and mitochondria are rich in oxidative reactions and are susceptible to oxidative stress damage. The interaction of oxidative stress and inflammation plays a key role in renal tissue destruction, irreversible loss of renal function, and progression of renal fibrosis. Antioxidant enzymes, such as superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px), protect cells from damage caused by oxygen free radicals. Malondialdehyde (MDA), one of the products of the reaction of lipids with oxygen free radicals, accumulates during oxidative stress. Cordyceps improves the redox properties of CKD by affecting the levels of NO, SOD and MDA in serum. In rat models of DN and membranous nephropathy, both Cordyceps militaris and HEA exhibited excellent ability to reduce oxidative stress, increase SOD and GSH, and decrease MDA levels. Using diclofenac or meloxicam to induce oxidative stress, HEA intervention significantly reduced ROS levels in human proximal renal tubular cells (HK-2). In adenine-induced chronic renal failure rats, Cordyceps cicadae and Paecilomyces cicadae effectively reduced serum urea and creatinine levels, improved renal histopathology, inhibited oxidative stress, and enhanced antioxidant capacity. In the CKD mouse model established by adenine gavage, Cordyceps sinensis polysaccharide increased SOD and GSH-PX, decreased ROS and MDA, improved histopathological staining, and decreased fibrosis-related proteins TGF-β1, α-SMA and type I collagen. Cordyceps and its related products are beneficial to reduce oxidative stress, but the mechanism is unclear.
Cordyceps can inhibit apoptosis
A variety of renal injury factors may trigger apoptosis, including ischemia/reperfusion injury, cisplatin-induced renal injury, and diabetic nephropathy. Apoptosis (programmed cell death) of glomerular endothelial cells, podocytes and TECs is closely related to RF. Inhibition of apoptosis as a therapeutic target can alleviate fibrosis. Cordyceps down-regulates apoptosis in ischemia/reperfusion injury and cyclosporine A-induced renal tubular dysfunction. Apoptosis is also considered to be an important mechanism of contrast-induced nephropathy (CIN). Cordyceps sinensis prevented CIN in diabetic rats by reducing the expression of apoptosis-related proteins Caspase-3 and Bax and increasing the expression of anti-apoptotic protein Bcl-2. The mechanism is to decrease the expression of JNK protein and increase the expression of ERK protein. Tubulointerstitial fibrosis is a typical pathological feature of hypertensive renal injury. In a spontaneously hypertensive rat model, Cicada flower reduced interstitial fiber deposition, α-SMA expression, apoptosis and Caspase-3 activity by regulating SIRT1/p53 signaling pathway. In vitro, the major renal injury caused by HBV infection is hepatitis B virus X (HBx)-induced apoptosis of renal TECs, which is associated with increased Caspase-3 and Caspase-9 activity and increased PI3K/Akt pathway activity. Cordyceps at least partially attenuated all of these HBx-induced responses by inhibiting the PI3K/Akt signaling pathway. Cordyceps and its related products have been shown to inhibit apoptosis in vivo and in vitro, but their mechanisms have not been unified.
Cordyceps regulates autophagy
Autophagy is a "self-depleting" cell death pathway that degrades most cytoplasmic components through the formation of autophagosomes and autolysosomes. Basic autophagy in the kidney is critical for maintaining renal homeostasis, structure, and function. That is, basal autophagy removes potentially dysfunctional organelles and long-lived proteins to maintain cellular homeostasis. Autophagy may be an adaptive response that ensures cell survival in response to environmental and intracellular stress. However, autophagy may also play a role in cellular dysfunction and organ pathology, such as AKI, AKI-CKD and DN. The role of autophagy in RF is controversial. It has been reported that persistent activation of autophagy in renal tubular cells promotes interstitial fibrosis, and inhibition of autophagy with chloroquine or selective deletion of Atg7 in proximal tubules alleviates RF in UUO mice. Several studies have also reported anti-fibrotic effects of autophagy, and in the UUO rat model, inhibition of autophagy by 3-methyladenine exacerbates RF, suggesting that autophagy may play an anti-fibrotic role by attenuating tubular cell damage. chemical effect. In STZ-induced DN mice, Cordyceps militaris polysaccharide (CMP) reduced renal collagen deposition and increased autophagy rate; promoted the expression of autophagy-specific proteins Atg5, Beclin1 and LC3; and decreased the expression of p62 protein in the kidney. This indicates that CMP can significantly enhance autophagy. Cordyceps cicadae may attenuate the expression of fiber-related proteins in a hypertensive nephropathy model. By down-regulating autophagy-related proteins LC3II and Beclin-1, it significantly inhibited autophagic vesicles, alleviated autophagic stress, and improved RF induced by hypertension. This effect may be attributed to the regulation of autophagy stress mediated by the SIRT1 pathway, which is achieved by regulating the autophagy regulator forkhead box-like O3a (FOXO3a) and oxidative stress. The role of Cordyceps in regulating autophagy is unquestionable, but autophagy itself is diverse and can be divided into microautophagy, chaperone-mediated autophagy, and macroautophagy, and macroautophagy is selective according to whether the substrate is It can be further divided into non-selective autophagy and selective autophagy. Since autophagy is dependent on the environment and may play different roles in different stages of the disease, different cell types respond inconsistently to autophagy activation, leading to a bidirectional effect of autophagy on the RF process. The regulatory role of autophagy in fibrosis remains to be further investigated.
Cordyceps reduces extracellular matrix deposition and fibroblast activation
Aberrant activation and proliferation of fibroblasts is considered a key cause of RF progression. Activated fibroblasts promote the production and release of ECM collagens I, III, IV and fibronectin and are the main source of ECM during scar tissue formation. Myofibroblasts in RF can be derived from mesenchymal fibroblasts, bone marrow-derived fibroblasts, renal TECs, ECs, pericytes, and macrophages. TEC can generate matrix to fibroblasts and myofibroblasts by EMT. In this process, TGF-β is the main driver. TGF-β promotes fibrosis by inducing fibroblast activation and proliferation as well as excessive synthesis and accumulation of ECM through downstream signaling pathways, such as SMAD, BMMP-7, and CTGF. Targeted inhibition of TGF-β and its downstream signaling pathways can delay fibrosis. Cordyceps nucleoside/base-rich extract increases the expression of E-cadherin; α-SMA, fibronectin and type I collagen in STZ-induced diabetic mice and high glucose-exposed HK-2 cells Decreased expression; inhibited EMT and ECM deposition; improved fibrotic morphology of tissues and cells. Cordyceps extract can effectively inhibit the phosphorylation of p38 and ERK without affecting the phosphorylation level of JNK, and has a synergistic effect on fibrosis with p38 or ERK inhibitors. Ergosterol peroxide in Cordyceps cicadae ameliorates TGF-β1-induced renal fibroblast activation via mitogen-activated protein kinase signaling pathway. In DN C57BL/6J mice and 5/6 nephrectomized rats, Cordyceps militaris and Cordyceps sinensis antagonize RF and reduce the expression of fibrosis-related proteins by inhibiting the TGF-β1 pathway. To further explore the downstream mechanism, 3′-deoxyadenosine interferes with TGF-β and bone morphogenetic protein signaling by downregulating Smad at the transcriptional level. In this way, it induces a reduction in collagen type I and α-SMA, mesenchymal myofibroblast numbers and fibrotic areas. Cordyceps and its extracts are potential therapeutic strategies against fibrosis through TGF-β/Smad and other pathways.
2. Clinical study of Cordyceps and its related products in the treatment of chronic kidney disease
One study enrolled 98 patients with CKD3 or CKD4 and randomly assigned them to a Cordyceps sinensis group (COG, patients taking 100 mg of Cordyceps militaris daily) and a control group (CG, patients taking a daily placebo of air-dried chickweed). After 3 months of treatment, Cordyceps militaris improved the inflammatory state and glomerular filtration membrane thickness of kidney tissue. Compared with CG group, COG group had lower CKD biomarkers (p<0.05); higher EGFR (p<0.05); decreased serum Cys-C, MPO and MDA levels; higher NO and SOD levels (p<0.05) ). Cordyceps sinensis reduced the protein and mRNA levels of TLR4/NF-κB signaling pathway (p<0.05). This suggests that Cordyceps militaris improves chronic kidney disease by affecting the TLR4/NF-κB redox signaling pathway.
In order to evaluate the efficacy of Cordyceps sinensis preparation Bailing Capsules combined with Losartan in the treatment of diabetic GS, 160 diabetic GS patients were randomly divided into an observation group and a control group; the observation group was treated with losartan and Bailing Capsules, and the control group was treated with Losartan Tan treatment. The total effective rate of the observation group was higher than that of the control group (p<0.05). After treatment, the levels of DBP, SBP, Scr, 24h UP, BUN, mALB and β2-MG in the observation group were lower than those in the control group, and GFR was higher than that in the control group (p<0.01). The TCM symptom scores in the observation group were lower than those in the control group (p<0.01). The serum SOD level of the observation group was also higher than that of the control group, and the levels of ROS, 8-OHdG, hs-CRP, TGF-β1 and SAA were also lower than those of the control group (p<0.01). Bailing Capsules combined with losartan can improve the curative effect; improve the biochemical indicators of hematuria, renal function and clinical symptoms; and reduce oxidative stress. However, this study has disadvantages of small sample size, short follow-up time and case selection bias.
In addition to single drugs or extracts, there are many compound preparations of traditional Chinese medicine, and some compound cordyceps also have the effect of protecting the kidneys. WH30+ is a Chinese herbal medicine preparation composed of rhubarb, salvia, cordyceps sinensis, motherwort, epimedium, astragalus, and Codonopsis. It has nephroprotective effects on both glycerol-induced acute renal failure and adenine-induced chronic renal failure in rats. The novel JY5 formula, CGA formula, and Fuzheng Huayu formula all have good efficacy in liver fibrosis, suggesting that these formulas may also be potential novel drugs for the treatment of RF.
3. Conclusion and Outlook
This study found that Cordyceps and its related products can attenuate RF through multiple pathways and targets, but the mechanisms are not independent of each other. Targeting TLR4 can reduce inflammation and oxidative stress through NF-κB, or activate the downstream TGF-β/Smad signaling pathway to promote ECM deposition and fibroblast activation. Acting on SIRT1 is important in regulating autophagy, oxidative stress, energy homeostasis and apoptosis. While multi-target targeting has certain advantages, it can also have more side effects. Existing clinical studies support the possibility of Cordyceps and its related products as adjuvants for conventional drugs to bring benefits to patients with chronic kidney disease. However, the existing clinical studies are limited by low quality and significant heterogeneity. RCTs with good methodological quality, favorable experimental design and large sample size are needed to evaluate the efficacy and safety of Cordyceps.
