Summary:
Chronic Kidney Disease and Focal Segmental Glomerulosclerosis are affecting humans all over the globe. Apolipoprotein L1 is the cause of kidney diseases, especially in African ancestry. Through CRISPR and Chinese Medication, kidney disease can be cured or controlled. CRISPR can target the risk variant and eliminate the high risk genotype from the variant. Chinese Medication can also be effective in targeting kidney disease.
Introduction:
One of the top causes of death in the world, is Chronic kidney disease (CKD). People of African origin are found with a higher variability and chance of suscepting to chronic kidney disease. Often found in correlation with the protein and risk variant, Apolipoprotein L1. The goal of this project is to find possible solutions to cure or rid Apolipoprotein L1 from causing CKD. If permanent solution are not available, we are to come up with the next best form of gene therapy that can ease the amount of diagnosed CKD across the world.
Background:
Apolipoprotein L1 is a protein that in humans is encoded by the APOL1 gene. APOL1 kidney risk variants is a cause of high rates of kidney disease in African ancestry. Risk variants are common and appear to have beneficial properties. Certain pathogens are protected against especially the trypanosomes (causing African sleeping sickness) through risk variants. APOL1 is localized in kidney cells, the G1 and G2 variants do not change APOL1 localization but alter its function(O’Toole 2014). Genetic variants affect the capacity to handle oxidative stress and alter APOL1 function and renal injury. The presence of two APOL1 risk variants is not sufficient enough to cause kidney disease. It is very likely that other genetic and environmental factors contribute to the modification of penetrance and expressivity of the APOL1 genotype. The likelihood that this genotype is present in the body is highly dependent on the individual’s ancestry. Neither skin color nor generalization of ancestry are good predictors of whether or not an individual patient may have kidney disease(Friedman 2011).
In regards to renal physiology and APOL 1’s function, the gene is inside the endosomal compartment (discontinuous closed membrane systems) and the presence of APOL1 risk variants leads to altered vesicular transport which transports materials between cellular compartments and between a cell and its environment. It also decreases autophagic flux, which is a destructive mechanism that disassembles unnecessary or dysfunctional components in the cell. It then shifts cells to inflammatory cell death pathway which is a cell death caused by inflammation.
When APOL 1 was first diagnosed in 2010 it was only believed to prevent African sleeping sickness. The beneficial properties of the APOL 1 led to an increase in its protein production. With more and more APOL1 risk variants appearing into the body, the risk variant no longer became a single protection against the sleeping sickness, but led to a homozygosity, the state of possessing two alike forms of a gene, and kidney disease (Friedman 2017).
Plan:
1. The benefits and proposed evolutionary origins of APOL1 and any role they can play in designing therapy.
Benefits/Role:
● Protect kidney cells against renal cell carcinoma (RCC) (Hu 2012).
○ Without an abundance of APOL 1, it proves to be helpful in preventing certain negative selections on cells and has not had a negative effect. Will have a negative effect if there are too much of the same protein/cell.
● protects human beings from infection by some trypanosomal parasites (O’Toole 2017)
○ Using information regarding the protection of humans from some trypanosomal parasites, can make plans to introduce a form of therapy where we have the weakness of the trypanosomal parasites.
2. The mechanism of APOL1 variants in immunity to trypansomal infection.
In order to expand, trypanosomes have evolved different mechanisms to block the trigger of the APOL1 lethal weapon: T.b. rhodesiense. It evolved a SRA glycoprotein, a molecule that is made up of a carbohydrate and a protein, that binds to APOL1 within the lysosome to rescind its toxicity, whereas T.b. gambiense– a specific glycoprotein (TgsGP) forms hydrophobic β-sheets that stiffen the endolysosomal membrane to prevent APOL1 membrane insertion and toxicity. In addition, to fully evade APOL1-mediated trypanolysis, APOL1 uptake is limited and APOL1 degradation is enhanced in T.b. gambiense. The APOL1 G1 and G2 renal risk alleles restore APOL1 mediated protection against T.b rhodesiense to prevent acute trypanosomiasis in humans. The G1 and G2 isoforms tend to induce cell death and tissue injury but at different levels of intoxicity but only G1 can kill trypanosome in vivo (Limou 2015).
3. The physiology of the kidney in osmotic regulation in the human body, and the medical implications of FSGS.
Kidneys regulate the osmotic pressure of blood through extensive filtration and purification also known as osmoregulation. Kidneys filter the blood, urine is the filtrate that eliminates waste from the body and into the bladder. The kidneys are surrounded by three layers, the renal fascia (the tough connective tissue layer), perirenal fat capsule(holds kidneys in place), and the renal capsule. FSGS is a rare disease that attacks the kidney’s filtering system (glomeruli) which causes serious scarring and leads to permanent kidney damage and failure. FSGS is most common in people of African American and Asian descent. FSGS is not caused by a single disease but rather scarring may happen because of an infection, drug, or disease that affects the entire body i.e diabetes, HIV, or sickle cell disease. FSGS are distinguished in two types, primary and secondary. Primary FSGS is when the disease happens on its own without a known cause. Secondary FSGS is when the disease is caused by another disease or drug.
4. Genetic mechanisms of APOL1 in inducing susceptibility to kidney disease. (Note this is poorly understood).
● APOL 1 is often found in the African ancestry, and most people assume it’s the main cause for an increase in chronic kidney disease. This not the case, however. Although APOL 1 does play a role in the progression of Chronic Kidney disease, it is not an intentional stimulator. Only an increase in homozygosity led to the deleterious effects of APOL 1 towards the kidney. APOL 1 originally protects humans/primates against the African sleeping sickness. And also becasue of this protein, humans are more resistant to T brucei, a type of trypanosome infection, than one of our closest primate relatives – chimpanzees (they lost the APOL 1 gene) (Pollak 2012)
● APOL 1 is a common (risk) variant and due to pathogen resistance, APOL 1 variants have higher allele frequencies. This high frequency causes the APOL 1 to act as a stimulant to the kidney disease.
● Using background information as well as understanding how APOL 1 induces susceptibility to kidney disease, will make it easier to come up with possible gene variants, mutations, or other forms of medication that can act as possible solutions to kidney disease.
5. Gene therapy approaches to target APOL1 to possibly cure associated renal disease.
Techniques of gene therapy have not been extensively applied to renal pathologies but have great potential to treat kidney disease at the cellular level and improve patient quality of life (Phillips 2008). CRISPR mechanism works to protect bacteria from repeated viral attacks which may possibly cure associated renal disease. CRISPR has already been successfully used to target important genes in many cell lines and organisms.
Solution/cure:
Propose a gene therapy, including molecular details of construction, how it will be delivered, and how it will be expressed. Be specific (must include information about the specific gene, any primers you use, techniques you will use like CRISPR – CAS9, etc). But remember – Your goal is to solve the problem, not to explain how much you know. So feel free to summarize basic procedures, as long as it’s clear you understood it.
1) CRISPR-CAS9, an engineering technique that targets changes in genomes and makes changes.
Treating CKD/FSGS with CRISPR:
1. Adaptation
a. Make a separate strand of DNA for the Apolipoprotein L1 gene and separate the high risk and low risk genotypes.
b. The strand of DNA without high risk genotypes, should be the “original”. The “other” strand will contain normal high and low risk genotypes of the Apolipoprotein L1.
c. The other strand will act as an invading virus that becomes processed into short segments (added to CRISPR sequence as spacers).
2. Production of the CRISPR RNA
a. The translation of the CRISPR RNA repeats while the new DNA undergoes transcription. It will produce a single-chain molecule and will be cut to CRISPR RNA short segments.
3. Targeting zealous material from the transcripted single chain molecule.
a. The CRISPR will then recognize and eliminate the unwanted high risk genotypes from the gene variant of Apolipoprotein L1.
4. Implement the new strand into a human of African origin until it adapts and forms many alleles.
2) Implementation of Chinese Medicine
The practice of traditional Chinese Medicine has long been used since empirical times. Its overall principle is to uphold the balance (Yin and Yang) of a person. You see, the Yin is the dark and negative energy, while Yang is the light and positive energy. These contrary forces complement each other in the world, and if one is off, it will affect the balance (health) of a person.
In terms of chronic kidney disease, herbal medications are commonly used in conjunction with western pharmacotherapy. In recent in vitro and animal studies, the therapeutic effects of traditional Chinese Herbal Medicine in regards to CKD has been effective. In order to heal CKD, the goal of traditional Chinese medicine is “replenishing vital energy and nourishing blood” (Zhong 2013).
Treating CKD/FSGS with Traditional Chinese Medicine:
1. Prescribe decoctions of multiple herbs
a. Effects of the herbs are in regards to “anti-inflammation, anti-oxidative, anti-fibrosis, regulation of immune system, anticoagulation, and improvement of metabolic disturbance” (Zhong 2013)
b. Herbal medicine such as Cordyceps sinensis and astragalus can help with kidney disease
2. Promote self healing and balance
a. Eating and exercising to maintain the yin and yang of one’s self
Risks:
Not all herbs and prescriptions have been tested. There is a possibility of the medicine not working and only giving the illusion that it works, (a placebo).
References
- Friedman DJ. A Brief History of APOL1 : A Gene Evolving. Seminars in Nephrology. 2017;37(6):508–513.
- Higashijima Yoshiki, Hirano Seiichi, Nangaku Masaomi, Nureki Osamu. “Applications of the CRISPR-Cas9 system in kidney research.” Kidney International. 2017; 92, 324-335.
- Hu C-AA, Klopfer EI, Ray PE. Human apolipoprotein L1 (ApoL1) in cancer and chronic kidney disease. FEBS Letters. 2012;586(7):947–955.
- Limou S., et al. “APOL1 Toxin, innate, immunity and kidney injury.” Kidney International. 2015; 88(1)”: 28-34
- O’Toole John F., et al. “Kidney disease: new technologies translate mechanisms to cure”. The Journal of Clinical Investigation . 2014;124(6):2294–2298.
- Pollak MR. Introduction: APOL1-Associated Kidney Disease. Seminars in Nephrology. 2017;37(6):489.
- Zhong Y, Deng Y, Chen Y, Chuang PY, He JC. Therapeutic use of traditional Chinese herbal medications for chronic kidney diseases. Kidney International. 2013;84(6):1108–1118.
Originally published 15.10.2019