Electrically‐stimulated acupuncture improves muscle function and increases renal blood flow through exosomes‐carried miR‐181
Authors: Zhang Aiqing H , Klein Janet D. , Wang Xiaonan H 
Published: June 2021

Introduction

our previous study found that acupuncture with low frequency electrical stimulation (Acu/LFES) can prevent muscle atrophy by increasing muscle protein anabolism in mouse models of chronic kidney disease, diabetes and denervation. Previous other studies have found that Acu/LFES improves renal blood flow and GFR in nephropathy patients and animals. We hypothesized that Acu/LFES benefits both skeletal muscle and kidney possibly through exosome carried microRNA.

Methods

Normal C57BL6 mice were awake without any anesthesia and appeared to be comfortable throughout the Acu/LFES. Acupuncture points selected were according to the WHO Standard Acupuncture guidelines. The mice were treated with Acu/LFES (anode: Yang Ling Quan, GB34 and cathode: Zu San Li, ST36) daily for 15 days. Renal plasma flow was measured by p‐Aminohippuric acid infusion. Glomerular filtration rate was determined using inulin infusion and measured with a FIT‐GFR kit. Exosomes were isolated by serial centrifugations. A miR deep sequencing assay and qPCR were used to identify microRNA expression in exosomes.

Results

Skeletal muscle grip function and muscle regeneration markers were increased after Acu/LFES treatment. Acu/LFES increased muscle cross‐sectional area in normal mice vs. sham Acu‐LFES mice. The abundance of Pax7, MyoD, myogenin and embryo myosin heavy chain was significantly increased by Acu‐LFES in soleus, extensor digitorum longus (EDL) and gastrocnemius muscle. The number of central nuclei was increased in Acu‐LFES treated muscle fibers. Interestingly, PAH clearance was increased by 45% in the mice after 15 minutes of muscle Acu/LFES versus mice with sham Acu/LFES (sham 6.1 ± 1.3 vs. Acu/LFES 8.9 ± 2.7 ml/min/g BW, P = 0.009, n=8/group). Inulin clearance was increased 39.8% (sham 65.9 ± 16.3 vs. Acu/LFES108.9 ± 19.7 ul/min/BW, P = 0.014). We found that Acu/LFES increases serum exosome abundance. When exosome secretion was blocked using GW4869, the Acu/LFES‐induced increase in renal blood flow and GFR were limited. To identify how exosomes regulate renal blood flow, we performed microRNA deep sequencing of exosomes isolated from mouse serum and found that 34 microRNAs were altered by Acu/LFES. Notably, miR‐181d‐5p, a microRNA that is involved in regulating translation of renin, was significantly increased in the serum exosomes of Acu/LFES treated mice. Using a luciferase reporter assay, we demonstrated that miR‐181 directly inhibits angiotensinogen, which provides potential evidence of Acu/LFES regulation of renal blood flow.

Conclusions

Acu/LFES not only improves muscle function, but also increases miR‐181 in serum exosomes and increases renal blood flow, suggesting that miR181 may regulate renal blood flow possibly by influencing the renin‐angiotensin system. This study provides new insights about the mechanism(s) of muscle‐organ cross talk through exosome‐delivered microRNA.

Support or Funding Information

NIH R01 AR060268 and AHA 17IBDG33780000

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.