Proteomic Investigation of Falciparum and Vivax Malaria for Identification of Surrogate Protein Markers

Abstract

This study was conducted to analyze alterations in the human serum proteome as a consequence of infection by malaria parasites Plasmodium falciparum and P. vivax to obtain mechanistic insights about disease pathogenesis, host immune response, and identification of potential protein markers. Serum samples from patients diagnosed with falciparum malaria (FM) (n = 20), vivax malaria (VM) (n = 17) and healthy controls (HC) (n = 20) were investigated using multiple proteomic techniques and results were validated by employing immunoassay-based approaches. Specificity of the identified malaria related serum markers was evaluated by means of analysis of leptospirosis as a febrile control (FC). Compared to HC, 30 and 31 differentially expressed and statistically significant (p<0.05) serum proteins were identified in FM and VM respectively, and almost half (46.2%) of these proteins were commonly modulated due to both of the plasmodial infections. 13 proteins were found to be differentially expressed in FM compared to VM. Functional pathway analysis involving the identified proteins revealed the modulation of different vital physiological pathways, including acute phase response signaling, chemokine and cytokine signaling, complement cascades and blood coagulation in malaria. A panel of identified proteins consists of six candidates; serum amyloid A, hemopexin, apolipoprotein E, haptoglobin, retinol-binding protein and apolipoprotein A-I was used to build statistical sample class prediction models. By employing PLS-DA and other classification methods the clinical phenotypic classes (FM, VM, FC and HC) were predicted with over 95% prediction accuracy. Individual performance of three classifier proteins; haptoglobin, apolipoprotein A-I and retinol-binding protein in diagnosis of malaria was analyzed using receiver operating characteristic (ROC) curves. The discrimination of FM, VM, FC and HC groups on the basis of differentially expressed serum proteins demonstrates the potential of this analytical approach for the detection of malaria as well as other human diseases.

Multifaceted Role of Heme during Severe Plasmodium falciparum Infections in India

“…Interestingly, there is a negative correlation between total heme and hemopexin levels in malaria, suggesting that during infection, mainly unbound heme is found in plasma. Hemopexin is a positive acute-phase protein, and previous studies have reported an increase in the circulating levels of hemopexin and its precursor during sepsis or in MM (23,24). However, decreased levels of hemopexin during severe sepsis also were associated with a low survival prognosis, highlighting the importance of hemopexin in the scavenging of free heme (23,25).…”

Proteomic analysis of Plasmodium falciparum induced alterations in humans from different endemic regions of India to decipher malaria pathogenesis and identify surrogate markers of severity

“…Patients co-infected with any other infectious diseases or other plasmodial infections such as vivax malaria or mixed infections (infected with both P. falciparum and P. vivax) were excluded from this study. Sample collection, serum separation, and storage were performed following the same protocol as reported earlier [13]. Serum samples were stored as multiple aliquots and uniformity was maintained in terms of number of freeze/thaw cycles while selection of the test (NSFM/SFM) and control (HC) samples for the comparative proteomic analysis to minimize the pre-analytical variables.…”

“…However, there is a dearth of similar proteomic analysis of severe falciparum malaria in Indian populations. In an earlier study we have reported the modulations in human serum proteome and various physiological pathways in uncomplicated non-severe falciparum malaria in an adult population from India [13]. In this study, serum samples from adult severe and non-severe falciparum malaria (SFM and NSFM) patients along with healthy community controls from three different endemic regions of India were investigated using 2D-DIGE and iTRAQbased quantitative proteomics in combination with ESI-Q-TOF and QExactive mass spectrometry.…”

Host-Based Diagnostics for Detection and Prognosis of Infectious Diseases

“…Proteomic analyses have identified signatures that distinguish Plasmodium falciparum malaria, Plasmodium vivax malaria, healthy controls, and leptospirosis with 95% accuracy (Ray et al, 2012). Thirty serum proteins distinguished P. falciparum from healthy controls, 31 proteins distinguished P. vivax from healthy controls, and 13 were differentially expressed when comparing the two malarial subtypes.…”