TMT-Based Plasma Proteomics Reveals Dyslipidemia Among Lowlanders During Prolonged Stay at High Altitudes

Identification of Suitable Reference Genes for Lowlanders Exposed to High Altitude and Ladakhi Highlanders

Sharma, Vandana, Rajeev Varshney, and Niroj Kumar Sethy. Identification of suitable reference genes for lowlanders exposed to high altitude and Ladakhi highlanders. High Alt Med Biol. 23:319-329, 2022. Background: Identifying a stable and reliable reference gene (RG) is a prerequisite for the unbiased and unambiguous analysis of gene expression data. It has become evident that conventionally used housekeeping genes such as beta-actin (ACTB), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and peptidylprolyl Isomerase A (PPIA) exhibit varied expression patterns under hypoxia. Hence, the identification of stable RGs for humans exposed to hypobaric hypoxia can enhance the accuracy of gene expression studies by limiting the negligent use of random housekeeping genes. Methods: Using TaqMan™ array-based quantitative real-time quantitative polymerase chain reaction, we evaluated the expression of 32 commonly used human RGs among lowlanders at Delhi (altitude 216 m, SL), lowlanders at Leh (altitude 3,524 m) after 1 day (HA-D1) and 7 days (HA-D7), as well as indigenous Ladakhi highlanders at the same altitude. The expression stability of the RGs was evaluated using geNorm, NormFinder, BestKeeper, Delta CT method, and RefFinder algorithms. Results: Our studies identify TATA-box binding protein (TBP), proteasome 26S subunit, ATPase 4 (PSMC4), and tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ) as the most stable human RGs for normalizing human gene expression under hypobaric hypoxia. In addition, we report the combination of TBP and cyclin-dependent kinase inhibitor 1B (CDKN1B) as the most stable RG for studying lowlander gene expression during high-altitude exposure. In contrast, RPL30 and 18S exhibited maximum variation across study groups and were identified as the least stable RGs.

Physical and mental health at high altitude of individuals doing yogic practices

Objectives

There is an increase trend in the past few years, in the number of people traveling to high altitude for recreational activities such as pilgrims, mountaineering, and climbing and for occupational purposes such as defense and mining which have resulted in increasing in hypoxia conditions and anxiety-related medical problems at high altitude. As it is known that mental stress affects brain and heart functions, a recent research performed on Sudarshan Kriya Yoga (SKY) further validated the effectiveness of SKY on participants (practicing SKY) as compared to control after quantifying mental stress. To study the physiological effect of SKY advance breathing technique when immediately ascends to high altitude, we wanted to study the level of stress and mental well-being of lowlanders at high altitude.

Materials and Methods

It is an interventional study performed at high altitudes, with low landers as participants where their biochemical and psychological parameters are being assessed.

Results

The result for biochemical parameter cholesterol, triglycerides, low-density lipoproteins (LDLs), high-density lipoproteins (HDLs), very low-density lipoproteins, LDL-HDL ratio, and cholesterol-HDL ratio showed a significant decrease in the pre- and post-analyses values with P ≤ 0.001. Acute mountain sickness (AMS), Warwick-Edinburgh Mental Well-being Scale, and State and Trait Anxiety Inventory (STAI) also show a decreasing trend with significant result in AMS, mental well-being, and non-significant in STAI p value is P = 0.016, P = 0.055, and P = 0.125, respectively.

Conclusion

We observed positive outcome both in for biochemical and stress-related parameters with SKY advance program practitioners who have rapidly ascend to high altitude.

Human adaptation to high altitude: a review of convergence between genomic and proteomic signatures

Both genomics- and proteomics-based investigations have identified several essential genes, proteins, and pathways that may facilitate human adaptive genotype/phenotype in a population-specific manner. This comprehensive review provides an up-to-date list of genes and proteins identified for human adaptive responses to high altitudes. Genomics studies for indigenous high-altitude populations like Tibetans, Andeans, Ethiopians, and Sherpas have identified 169 genes under positive natural selection. Similarly, global proteomics studies have identified 258 proteins (± 1.2-fold or more) for Tibetan, Sherpa, and Ladakhi highlanders. The primary biological processes identified for genetic signatures include hypoxia-inducible factor (HIF)-mediated oxygen sensing, angiogenesis, and erythropoiesis. In contrast, major biological processes identified for proteomics signatures include 14–3-3 mediated sirtuin signaling, integrin-linked kinase (ILK), phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT), and integrin signaling. Comparing genetic and protein signatures, we identified 7 common genes/proteins (HBB/hemoglobin subunit beta, TF/serotransferrin, ANGPTL4/angiopoietin-related protein 4, CDC42/cell division control protein 42 homolog, GC/vitamin D-binding protein, IGFBP1/insulin-like growth factor-binding protein 1, and IGFBP2/insulin-like growth factor-binding protein 2) involved in crucial molecular functions like IGF-1 signaling, LXR/RXR activation, ferroptosis signaling, iron homeostasis signaling and regulation of cell cycle. Our combined multi-omics analysis identifies common molecular targets and pathways for human adaptation to high altitude. These observations further corroborate convergent positive selection of hypoxia-responsive molecular pathways in humans and advocate using multi-omics techniques for deciphering human adaptive responses to high altitude.