Transcriptomics in placentas of women with sickle cell disease

Author(s)

Letícia de Carvalho Baptista

• Document type: Doctoral Thesis
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2019-07-12

Examining board members

Mônica Barbosa de Melo; Nicola Amanda Conran Zorzetto; Cláudia Vianna Maurer Morelli; Daniela Sanchez Bassères

• Advisor: Maria Laura Costa do Nascimento; Mônica Barbosa de Melo

Abstract

Sickle cell diseases (SCD) are a group of genetic pathologies that have as common characteristic the presence of hemoglobin (Hb) S. The clinical manifestation of this disease is very heterogeneous, so that different patients may present significantly different clinical evolutions. Almost all organs can be affected, including the placenta, which can have structural and functional abnormalities. The pregnancy in women with SCD presents risks to the mother and fetus, such as: increased maternal mortality and morbidity, preeclampsia (PE), preterm birth, fetal growth restriction and perinatal mortality. In addition, the pregnancy is accompanied by increased incidence of episodes of pain, infections, pulmonary complications and thromboembolic events. Specialized prenatal follow-up and clinical, laboratory, and serial transfusion procedures have had a major impact on reducing maternal and neonatal mortality; however, the morbidity associated with SCD is still high and the mechanisms responsible for triggering these complications and the pathophysiology involved are not well explored. The main objective of this investigation was to evaluate the gene expression profile in placentas of women with SCD by means of RNA sequencing. For this, we proposed a case-control study, with three groups: pregnant women with sickle cell anemia (HbSS, n=10), pregnant women with SC hemoglobinopathy (HbSC, n=15), and group of pregnant women without SCD (HbAA, n = 21). The results showed differences in expression in some genes such as NOS2 (fold change = 4.52; FDR = 0.003), HLAG (fold change = 5.56; FDR = 6x10-7), ASCL2 (fold change = 3.61; FDR = 0.005), CXCL10 (fold change = -3.66; FDR = 0.020) and IL1R2 (fold change = 3.92; FDR = 0.0002) for the HbSC group and S100A8 (fold change = -3.82; FDR = 0.013), CPXM2 (fold change = 4.57; FDR = 0.020), CXCL10 (fold change = -4.59; FDR = 0.013), CXCL11 (fold change = -3.72; FDR = 0.024) and CAMP (fold change = -4.55; FDR = 0.020) for the HbSS group. Differentially expressed genes are mainly associated with migration, trophoblast differentiation and inflammation. The causes leading to altered gene expression in placentas of sickle cell patients are not fully understood, but the presence of heme and vaso-occlusion, with cycles of ischemia and reperfusion, may contribute to the emergence of an environment improper for placental physiology, altering nutrient supply and metabolic exchange for fetal growth. Most of the patients in our study were undergoing regular prophylactic transfusion after 28 weeks in order to reduce the amount of HbS below 30% and thus reduce sickling attacks. However, only with prophylactic transfusion in the third trimester is it not possible to completely prevent complications. Knowledge of pathways that may be altered with increased free Hb and heme in placentas may potentially contribute to a better understanding of clinical complications and therapy for women with SCD in the future (AU)

• FAPESP's process: 15/08330-5 - Transcriptomics in placentas of women carrier of sickle cell disease.
• Grantee: Letícia de Carvalho Baptista
• Support Opportunities: Scholarships in Brazil - Doctorate