Hydrodynamic Renal Pelvis Injection for Non-viral Expression of Proteins in the Kidney

Summary

This protocol describes a method to inject plasmid DNA into the mouse kidney via the renal pelvis to produce transgene expression specifically in the kidney.

Abstract

Hydrodynamic injection creates a local, high-pressure environment to transfect various tissues with plasmid DNA and other substances. Hydrodynamic tail vein injection, for example, is a well-established method by which the liver can be transfected. This manuscript describes an application of hydrodynamic principles by injection of the mouse kidney directly with plasmid DNA for kidney-specific gene expression. Mice are anesthetized and the kidney is exposed by a flank incision followed by a fast injection of a plasmid DNA-containing solution directly into the renal pelvis. The needle is kept in place for ten seconds and the incision site is sutured. The following day, live animal imaging, Western blot, or immunohistochemistry may be used to assay gene expression, or other assays suited to the transgene of choice are used for detection of the protein of interest. Published methods to prolong gene expression include transposon-mediated transgene integration and cyclophosphamide treatment to inhibit the immune response to the transgene.

Introduction

The hydrodynamic tail vein injection technique has become a commonly used way to achieve high levels of gene expression in mouse liver^1,2. The kidneys are also transfected by this technique at a much lower level, approximately 100-fold less³. The hydrodynamic renal pelvis injection described here provides a simple way to control the specificity of organ expression through physical means using the same hydrodynamic principles that have been established previously in liver^4,5, muscle⁶, and other organs

Protocol

All methods described here have been approved by the Institutional Animal Care and Use Committees (IACUCs) of Baylor College of Medicine and Vanderbilt University Medical Center.

1. Prepare the DNA solution for injection

1. Select the plasmid(s) to express the transgene(s) carefully to maximize the desirable characteristics to improve transfection efficiency and transgene expression.
   NOTE: Hydrodynamic renal pelvis injection of plasmids to express the fluorescent marker TdTomato, the hormone erythropoietin (Epo), and firefly luciferase have been previously described¹¹. If there is not a well-developed a....

Results

The surgery and injection technique are simple to perform once mastered, requiring no major equipment or expensive materials. If new to flank-incision kidney surgery, one training day on several mice scheduled for euthanasia should be allowed in which the mice are not recovered following surgery because the first attempt at this surgery may take much longer than normal. Alternatively, investigators familiar with similar techniques may find it quite simple. Carefully follow the illustratio.......

Discussion

In this protocol a robust method for achieving reproducible gene expression specifically in the kidney is described. In the hands of a moderately experienced surgeon we have found the percentage of mice transfected by this technique to be in the range of 50-100%, depending on mouse age and the sensitivity of the readout of the transgene. The level of luciferase gene expression was above background for several months in mice receiving piggyBac transposons and completely maintained for several weeks in immunocompr.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
AnaSed Xylazine	Patterson Veterinary	07-808-1947	Anesthetic - Not controlled substance
BD Insulin Syringe 0.5 mL 29G 1/2 Inch	Cardinal Health	309306	Required syringes
Buprenex	Pharmacist/Veterinarian		Analgesia - Controlled Substance
Dynarex Disposable Towel Drape	Thermo Fisher Scientific	19-310-671	Place over heat pad
EndoFree Plasmid Maxi Kit	Qiagen	12362	Use only endotoxin-free plasmid DNA
Endosafe Gel-Clot LAL Rapid Positive Control	Charles River	PC200	Positive control for endotoxin test
Endosafe Gel-Clot LAL Rapid Single Test Vial	Charles River	R13500	Endotoxin test
Extra Fine Micro Dissecting Scissors	Roboz Surgical Instrument	RS-5882	Surgical tool
Fisherbrand Instant Sealing Sterilization Pouch - 9"	Thermo Fisher Scientific	01-812-51	For autoclaving surgical tools
Gaymar Heat Pump	Paragon Medical	TP-700	Water-circulating heat pump
Germinator 500	Roboz Surgical Instrument	DS-401	To reuse surgical tools during surgery
Graefe Forceps	Roboz Surgical Instrument	RS-5136	Surgical tool
Graefe Tissue Forceps	Roboz Surgical Instrument	RS-5153	Surgical tool
Halsey Needle Holder, 5" Length	Roboz Surgical Instrument	RS-7841	Surgical tool
Heat pads - 15" x 21" - need at least 3	Paragon Medical	TP22G	For use with Gaymar Heat Pump
IsoFlo (Isoflurane, USP)	Abbott Animal Health	5260-04-05	For imaging and euthanasia
Isotec Isoflurane Delivery System Vaporizor	Smiths Medical	VCT3K2	For imaging and euthanasia
Ketamine	Pharmacist/Veterinarian		Anesthetic - Controlled Substance
Kimwipes	Kimberly-Clark Professional	34120	Laboratory tissues
Living Image software	Caliper Life Sciences		For live animal imaging
Luciferin	Perkin Elmer	122796	For live animal imaging
Nanodrop 2000	Thermo Scientific	ND-2000-US-CAN	Spectrophotometer for DNA measurement
Prevantics Swabs	Thermo Fisher Scientific	23-100-110	For skin surgery prep
Prolene 5-0 sutures Taper 30"	Thermo Fisher Scientific	NC0256891	Non-absorbable sutures for skin
Puralube Brand Opthalmic Ointment	Patterson Veterinary	07-888-2572	To keep eyes moist during surgery
Trans IT - QR Hydrodynamic Delivery Solution	Mirus Bio	MIR-5240	Hydrodynamic delivery buffer for diluting DNA
Vicryl 5-0 Sutures J303H	Thermo Fisher Scientific	NC9816710	Absorbable sutures for muscle layer
Wahl Mini Arco Clipper	Med-Vet International	8787-1550	Shaver for skin prep
Xenogen IVIS 200	Caliper Life Sciences		For live animal imaging