HK-2 Cells - Probing Kidney Function and Pathology with HK-2 Cells in Renal Research
HK-2 is an immortalized human kidney epithelial cell line commonly used in toxicology research. Researchers evaluate the effects of environmental toxins on these kidney cells. In addition, they also employ HK-2 cells to investigate kidney diseases and their underlying mechanisms.
This article will explain almost the essential information about HK-2 cells, including their general characteristics, cell culture conditions, research applications, and much more. You will learn the following:
- HK-2 cells: Origin and general characteristics
- HK-2 cell line: Culturing information
- Advantages & Limitations of HK-2 cells
- Applications of HK-2 cell line in research
- HK-2 cells: Research publications
- Resources for HK-2 cell line: Protocols, Videos, and More
1. HK-2 cells: Origin and general characteristics
The origin and general characteristics of a cell line are imperative to know for proper handling, maintenance, and use of a cell line. This section of the article will cover the following: What are HK-2 cells in human kidney 2? What is the role of HK2? What are HK2 cells? What is the origin of the HK-2 cell line? What are the HK-2 cell size and morphology?
- Human Kidney 2 (HK-2) cells are a type of proximal tubular cells originating from a European adult's normal kidney tissue. The HK-2 cell line was established by transfecting kidney cells with a recombinant retrovirus comprising the E6/E7 genes of human papillomavirus 16. This experiment caused the immortalization and establishment of a continuously growing HK-2 kidney epithelial cell line.
- HK-2 cells exhibit an epithelial morphology.
- The HK-2 cell size ranges between 17.4 -18.6 µm in diameter. The mean diameter is 18.2 µm [1].
2. HK-2 cell line: Culturing information
Information about the human kidney 2 cell line culturing can significantly help you before working with it. Imperative HK-2 cell culture information is mentioned in this section of the article. You will know: Are HK-2 cells adherent? What is the doubling time of HK-2 cells? What medium is used to culture HK-2 cells?
Key Points for Culturing HK-2 Cells
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Population Doubling Time: |
The doubling time for HK-2 cells ranges between 47.3 h and 61.7 h. |
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Adherent or in Suspension: |
HK-2 kidney epithelial cell line is adherent. |
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Sub-cultivation ratio: |
HK-2 cells are sub-cultivated at a ratio of 1:2 to 1:4. Adherent HK-2 cells are washed with 1 x PBS and incubated at ambient temperature for 8 to 10 minutes after adding Accutase solution. Culture media is added to the dissociated cells and centrifuged. Collected cells are carefully resuspended and poured into new flasks for culturing. |
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Growth Medium: |
Keratinocyte cell line medium containing 10% fetal bovine serum, 0.05 mg/ml bovine pituitary extract (BPE) & 5 ng/ml epidermal growth factor (EGF) is ideal HK-2 cell medium. Media should be replaced every 2 to 3 days a week. |
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Growth Conditions: |
Human kidney 2 cell line cultures are kept in a humidified incubator with a 5% CO2 supply at 37°C. |
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Storage: |
Frozen cells are stored in the vapour phase of liquid nitrogen or at below -150 °C temperature in an ultra-low temperature freezer. |
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Freezing Process and Medium: |
CM-1 or CM-ACF freezing media are ideal for HK-2 cell freezing. Briefly, a slow freezing method is opted allowing only 1 degree Celsius per minute drop in temperature and protecting cells from any shock. |
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Thawing Process: |
Frozen cells are thawed in a water bath set at 37 degrees Celsius temperature. These cells are added with fresh culture media and resuspended. Afterwards, cells are dispensed into a new flask containing growth media. After 24 hours media is replaced to remove freezing media components. |
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Biosafety Level: |
HK-2 cell cultures are maintained in biosafety level 1 laboratories. |
3. Advantages & Limitations of HK-2 cells
HK-2 is a widely used human proximal tubule epithelial cell line. Like other cell lines, it is also associated with some advantages and limitations. This section will discuss some key pros and cons of the human kidney 2 cell line.
Advantages
The main advantages of the HK-2 cell line include:
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Well-characterized |
The HK-2 cell line is extensively characterized in terms of its morphology, size, and genome. Numerous research studies have been conducted on these normal kidney cells. |
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Immortalized |
HK-2 is a continuous cell line with an extended life span, allowing it to be propagated through several passages. This feature ensures a continuous supply of cells for laboratory experiments. |
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Proximal tubule epithelial characteristics |
HK-2 cells exhibit a well-differentiated phenotype characteristic of proximal tubule cells (PTCs) found in the human kidney. This unique trait makes HK-2 cells a valuable in vitro model for studying renal physiology, cell processes, and responses to various stimuli. |
Limitations
Here are some limitations of the HK-2 cell line:
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In vitro model |
HK-2 serves as an in vitro model of normal kidney cells, particularly exhibiting characteristics of proximal tubule epithelial cells. However, it may not fully replicate the complexity of the human kidney tissue and the microenvironment found in vivo. |
4. Applications of HK-2 cell line in research
The HK-2 cell line has numerous applications in toxicology research. Here, we have discussed some specific and significant research uses of this human proximal tubular cell line.
- Renal physiology: HK-2 cells are commonly used to study normal renal physiology and functions. Researchers employ these proximal tubule epithelial cells to investigate ion channels, transport processes, and other cellular mechanisms regulating kidney homeostasis. Such as, researchers studied the role of Transient Receptor Potential Channel 6 (TRPC6) channels in (+)-Conocarpan (CNCP), a neolignan, induced cell death in kidney epithelial cells, HK-2 [2].
- Kidney diseases: The human kidney 2 cell line is utilized to investigate different kidney diseases, i.e., acute kidney injury and diabetic nephropathy, and their underlying cell and molecular mechanisms. Such as research found that klotho protein methylation levels are linked to renal damage. Decreasing the methylation of the Klotho gene promoter can enhance its expression and alleviate renal damage induced in diabetic db/db mice models and high glucose treated HK-2 cells [3].
- Toxicology studies: HK-2 cells are a great research tool for evaluating the potential effects of various drugs, chemicals, and environmental pollutants. The studies may help researchers evaluate drug safety and side effects on kidney cells. Such as a study published in 2022 evaluated the potential effects of a natural herb Polygonatumkingianum (PK) polysaccharides and aqueous extract on uranium-induced nephrotoxicity in HK-2 cells. They found that PK exerts protective effects and prevents uranium poisoning in kidney cells [4].
5. HK-2 cells: Research publications
The following are some interesting research publications featuring HK-2 kidney epithelial cells.
This study in Diabetes, Metabolic Syndrome, and Obesity (2022) proposed that circular RNA HIPK3 can diminish the HK-2 cell proliferation inhibition caused by high glucose toxicity. In addition, it can inhibit cell death by regulating miR-326/miR-487a-3p/SIRT1 cascade.
This research publication in Nanomedicine (2020) assessed different toxicity mechanisms of gold nanoparticles (AuNPs) in 786-0 cancer cells and HK-2 proximal tubule epithelial cells.
High-glucose induced toxicity in HK-2 cells can be alleviated by inhibition of miRNA-320c
This article was published in Renal Failure (2022). The findings state that microRNA-320c can reduce the high glucose-induced toxicity in kidney cells (HK-2) by targeting PTEN and inhibiting the PI3K/AKT signalling.
Mesenchymal Stem Cell-Derived Exosomes Attenuate Epithelial–Mesenchymal Transition of HK-2 Cells
This study in Tissue Engineering Part A (2022) proposed that exosomes derived from mesenchymal stem cells prevent the epithelial-to-mesenchymal transition of HK-2 kidney cells.
The Journal of Pharmacy and Pharmacology (2019) article states that lncRNA TapSAKI enhances HK-2 inflammation response and cell death by regulating the microRNA-22/PTEN/TLR4/NF-κB signalling pathway.
6. Resources for HK-2 cell line: Protocols, Videos, and More
HK-2 is a famous cell line. Here are some resources describing the HK-2 cell culture protocol.
- HK-2 cell culture: This website is enriched with HK-2 cell culture information. Such as it provides HK-2 cell medium recipe, passaging protocol, and protocol for handling and maintaining proliferative and cryopreserved cultures.
- Cell passaging: This video will help you learn a general splitting or passaging protocol for adherent cell lines.
References
- Handl, J., et al., The effect of repeated passaging on the susceptibility of human proximal tubular HK-2 cells to toxic compounds. Physiological Research, 2020. 69(4): p. 731.
- Yang, G., et al., Activation of TRPC6 channels contributes to (+)-conocarpan-induced apoptotic cell death in HK-2 cells. Food and Chemical Toxicology, 2019. 129: p. 281-290.
- Yang, X.H., et al., EGCG attenuates renal damage via reversing klotho hypermethylation in diabetic db/db mice and HK-2 cells. Oxidative Medicine and Cellular Longevity, 2020. 2020.
- Li, W., et al., Protective effects of Polygonatum kingianum polysaccharides and aqueous extract on uranium-induced toxicity in human kidney (HK-2) cells. International Journal of Biological Macromolecules, 2022. 202: p. 68-79.