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Zhe Han

$3 million NIH grant to study APOL1 and HIV synergy

Zhe Han

Zhe Han, Ph.D., (pictured) and Patricio E. Ray, M.D., have received a $3 million, five-year grant from the National Institutes of Health to study the mechanisms behind APOL1 and HIV nephropathies in children, using a combination of Drosophila models, cultured human podocytes and a preclinical model.

Two Children’s researchers have received a $3 million, five-year grant from the National Institutes of Health (NIH) to study the mechanisms of APOL1 and HIV nephropathies in children, using a combination of Drosophila models, cultured human podocytes and a preclinical model.

The APOL1 genetic variants G1 and G2, found almost exclusively in people of African ancestry, lead to a four-fold higher risk of end-stage kidney disease. HIV infection alone also increases the risk of kidney disease but not significantly. However, HIV-positive people who also carry the APOL1 risk alleles G1 or G2 are about 30 times more likely to develop HIV-nephropathy (HIVAN) and chronic kidney disease.

For more than 25 years, Children’s pediatric nephrology program has studied HIV/renal diseases and recently developed Drosophila APOL1-G0 and G1 transgenic lines. That pioneering research suggests that HIV-1 acts as a “second hit,” precipitating HIV-renal disease in children by infecting podocytes through a mechanism that increases expression of the APOL1-RA beyond toxic thresholds.

With this new infusion of NIH funding, labs led by Zhe Han, Ph.D., and Patricio E. Ray, M.D., will determine the phenotype of Drosophila Tg lines that express APOL1-G0/G1/G2 and four HIV genes in nephrocytes to assess how they affect structure and function. The teams also will determine whether APOL1-RA precipitates the death of nephrocytes expressing HIV genes by affecting autophagic flux.

“Our work will close a critical gap in understanding about how HIV-1 interacts with the APOL1 risk variants in renal cells to trigger chronic kidney disease, and we will develop the first APOL1/HIV transgenic fly model to explore these genetic interactions in order to screen new drugs to treat these renal diseases,” says Dr. Ray, a Children’s nephrologist.

While a large number of people from Africa have two copies of APOL1 risk alleles, they do not necessarily develop kidney disease. However, if a patient has two copies of APOL1 risk alleles and is HIV-positive, they almost certainly will develop kidney disease.

Patricio Ray

“Our work will close a critical gap in understanding about how HIV-1 interacts with the APOL1 risk variants in renal cells to trigger chronic kidney disease, and we will develop the first APOL1/HIV transgenic fly model to explore these genetic interactions in order to screen new drugs to treat these renal diseases,” says Dr. Ray, a Children’s nephrologist.

“Many teams want to solve the puzzle of how APOL1 and HIV synergize to cause kidney failure,” says Han, associate professor in Children’s Center for Genetic Medicine Research. “We are in the unique position of combining a powerful new kidney disease model system, Drosophila, with long-standing human podocyte and HIVAN studies.”

The team hypothesizes that even as an active HIV infection is held in check by powerful new medicines, preventing the virus from proliferating or infecting new cells, HIV can act as a Trojan horse by making the human cells it infects express HIV protein.

To investigate this hypothesis, the team will create a series of fly models, each expressing a major HIV protein, and will test the genetic interaction between these HIV genes with APOL1. Similar studies also will be performed using cultured human podocytes. Identified synergy will be studied further using biochemical and transcription profile analyses.

Drosophila is a basic model system, but it has been used to make fundamental discoveries, including genetic control of how the body axes is determined and how the biological clock works – two studies that led to Nobel prizes,” Han adds. “I want to use the fly model to do something close to human disease. That is where my research passion lies.”

Lawrence D'Angelo

Being a young parent while also HIV positive

Lawrence D'Angelo

“We realize that at some point in time, these patients will have to transition their care to an adult setting, and they will confront a different kind of health system,” says Lawrence D’Angelo, M.D., M.P.H. “We want to make sure all of their providers will be able to help them advocate for themselves and for their children.”

By the time the human immunodeficiency virus (HIV) – the virus that causes AIDS – first came to the public consciousness in the 1980s, it was clear that infected pregnant mothers readily pass it to their babies. For those infected babies to eventually have their own children was inconceivable then, says Lawrence J. D’Angelo, M.D., M.P.H., adolescent medicine specialist at Children’s National Health System. Before the advent of antiretroviral therapy, AIDS was universally fatal.

Now, about 22 percent of young adults with HIV have lived with this disease their entire lives. And like many people this age, they’re exploring romantic relationships, sex and – for some – parenthood. This unexpected turn of events, Dr. D’Angelo explains, has left many health care providers unprepared.

“We never expected that these individuals would live to reach early adulthood, so we certainly didn’t expect them to be involved in parenting,” he says. “We have no real knowledge of what to expect from them or how best to support them because we don’t understand what they’re going through.”

To learn more about these young parents living with perinatally acquired HIV (PHIV), Dr. D’Angelo worked with Cynthia Fair, professor of human services studies and public health studies coordinator at Elon University. The two conducted a qualitative assessment of parents with PHIV. After recruiting 17 individuals who fit this description directly from Dr. D’Angelo’s practice, interviewers on the research team sat down with study participants to have a conversation about what it was like to parent while also being HIV positive. They asked standard questions, such as: What do you think makes a good parent? And, describe your relationship with your parents or caregivers. How does this relate, if at all, to your views on parenthood?

The team then transcribed these interviews and fed the text into a qualitative analysis program. With the aid of this software, and their own manual analysis, the researchers found several themes emerge from the conversations.

About 90 percent of the interviews focused on challenges universal to nearly every parent: Worries about a baby taking a bottle or sleeping through the night, struggles with discipline, concerns about money. “For the most part, these are young parents with a chronic illness just trying to be good parents,” says Fair, lead author of the study published Nov. 1, 2017 in AIDS Patient Care and STDs.

However, she adds, HIV inserts an added layer of complexity. Many of the parents said they felt deprived of the opportunity to enjoy lives as long and healthy as their peers. Consequently, having a child carried a sense of pressure to accomplish more in life for their children and to leave a positive legacy. Some worried that their own HIV status would stigmatize their children and that people outside their families would automatically assume their children were HIV positive when they weren’t.

All but one parent in the study had a child who was HIV negative, but even those children require regular testing to make sure they maintain that status. Parents with infants prescribed preventive protocols spoke about the exhaustion of having to deliver prophylactic medicines around the clock. The sole parent in the study with an HIV-positive child was separated from the baby’s father; she talked about the stress of not knowing whether her baby was receiving the necessary medicines to stay healthy when the child wasn’t with her.

These young parents also spoke with interviewers about the role their own pediatric care providers played in helping them make the transition to parenthood. For example, social workers on one study participant’s care team stepped in when she had nowhere to live, finding her an appropriate shelter. Another talked about how her desire to be a good parent was strongly influenced by the care she was given by her medical providers growing up. Many of the study participants had lost one or both parents to HIV or had absentee parents due to incarceration or other causes, says Fair, making their relationships with their medical team one of the few constants they could count on.

That’s why helping care providers develop a deep understanding of the perspectives of PHIV parents is even more important, particularly as these individuals move from pediatric to adult care settings, says Dr. D’Angelo, the study’s senior author and director of the Youth Pride and Burgess Clinics at Children’s National.

“We realize that at some point in time, these patients will have to transition their care to an adult setting, and they will confront a different kind of health system,” he says. “We want to make sure all of their providers will be able to help them advocate for themselves and for their children.”