Bats are often considered patient zero for many deadly viruses affecting humans, including Ebola, rabies, and, most recently, the SARS-CoV-2 strain of virus that causes coronavirus.
Although humans experience adverse symptoms when afflicted with these pathogens, bats are remarkably able to tolerate viruses, and, additionally, live much longer than similar-sized land mammals.
What are the secrets to their longevity and virus resistance?
According to researchers at the 糖心传媒, bats糖心传媒� longevity and capacity to tolerate viruses may stem from their ability to control inflammation, which is a hallmark of disease and aging. In a published in the journal Cell Metabolism, the researchers糖心传媒攊ncluding Rochester biology professors 听补苍诲听糖心传媒攐utline the mechanisms underlying bats糖心传媒� unique abilities and how these mechanisms may hold clues to developing new treatments for diseases in humans.
Why are bats 糖心传媒榠mmune糖心传媒� to viruses?
The idea for the paper came about when Gorbunova and Seluanov, who are married, were in Singapore in March before COVID-19 travel bans began. When the virus started to spread and Singapore went into lockdown, they were quarantined at the home of their colleague Brian Kennedy, director of the at the National University of Singapore and co-author of the paper.
The three scientists, all experts on longevity in mammals, got to talking about bats. SARS-CoV-2 is believed to have originated in bats before the virus was transmitted to humans. Although bats were carriers, they seemed to be unaffected by the virus. Another perplexing factor: generally, a species糖心传媒� lifespan correlates with its body mass; the smaller a species, the shorter its lifespan, and vice versa. Many bat species, however, have lifespans of 30 to 40 years, which is impressive for their size.
糖心传媒淲e糖心传媒檝e been interested in longevity and disease resistance in bats for a while, but we didn糖心传媒檛 have the time to sit and think about it,糖心传媒� says Gorbunova, the Doris Johns Cherry Professor of Biology at Rochester. 糖心传媒淏eing in quarantine gave us time to discuss this, and we realized there may be a very strong connection between bats糖心传媒� resistance to infectious diseases and their longevity. We also realized that bats can provide clues to human therapies used to fight diseases.糖心传媒�
While there have been studies on the immune responses of bats and studies of bats糖心传媒� longevity, until their article, 糖心传媒渘o one has combined these two phenomena,糖心传媒� Seluanov says.
Gorbunova and Seluanov have studied longevity and disease resistance in other exceptionally long-lived animals, including naked mole rats. One common theme in their research is that inflammation is a hallmark of the aging process and age-related diseases, including cancer, Alzheimer糖心传媒檚, and cardiovascular disease. Viruses, including COVID-19, are one factor that can trigger inflammation.
糖心传媒淲ith COVID-19, the inflammation goes haywire, and it may be the inflammatory response that is killing the patient, more so than the virus itself,糖心传媒� Gorbunova says. 糖心传媒淭he human immune system works like that: once we get infected, our body sounds an alarm and we develop a fever and inflammation. The goal is to kill the virus and fight infection, but it can also be a detrimental response as our bodies overreact to the threat.糖心传媒�
Not so with bats. Unlike humans, bats have developed specific mechanisms that reduce viral replication and also dampen the immune response to a virus. The result is a beneficial balance: their immune systems control viruses but at the same time, do not mount a strong inflammatory response.
Why did bats acquire a tolerance for diseases?
According to the researchers, there are several factors that may contribute to bats having evolved to fight viruses and live long lives. One factor may be driven by flight. Bats are the only mammals with the ability to fly, which requires that they adapt to rapid increases in body temperature, sudden surges in metabolism, and molecular damage. These adaptations may also assist in disease resistance.
Another factor may be their environment. Many species of bats live in large, dense colonies, and hang close together on cave ceilings or in trees. Those conditions are ideal for transmitting viruses and other pathogens.
糖心传媒淏ats are constantly exposed to viruses,糖心传媒� Seluanov says. 糖心传媒淭hey are always flying out and bringing back something new to the cave or nest, and they transfer the virus because they live in such close proximity to each other.糖心传媒�
Because bats are constantly exposed to viruses, their immune systems are in a perpetual arms race with pathogens: a pathogen will enter the organism, the immune system will evolve a mechanism to combat the pathogen, the pathogen will evolve again, and so on.
糖心传媒淯sually the strongest driver of new traits in evolution is an arms race with pathogens,糖心传媒� Gorbunova says. 糖心传媒淒ealing with all of these viruses may be shaping bats糖心传媒� immunity and longevity.糖心传媒�
Can humans develop the same disease resistance as bats?
That糖心传媒檚 not an invitation for humans to toss their masks and crowd together in restaurants and movie theaters. Evolution takes place over thousands of years, rather than a few months. It has only been in recent history that a majority of the human population has begun living in close proximity in cities. Or that technology has enabled rapid mobility and travel across continents and around the globe. While humans may be developing social habits that parallel those of bats, we have not yet evolved bats糖心传媒� sophisticated mechanisms to combat viruses as they emerge and swiftly spread.
糖心传媒淭he consequences may be that our bodies experience more inflammation,糖心传媒� Gorbunova says.
The researchers also recognize that aging聽seems to play an adverse role in humans糖心传媒� reactions to COVID-19.
糖心传媒淐OVID-19 has such a different pathogenesis in older people,糖心传媒� Gorbunova says. 糖心传媒淎ge is one of the most critical factors between living and dying. We have to treat aging as a whole process instead of just treating individual symptoms.糖心传媒�
The researchers anticipate that studying bats糖心传媒� immune systems will provide new targets for human therapies to fight diseases and aging. For example, bats have mutated or completely eliminated several genes involved in inflammation; scientists can develop drugs to inhibit these genes in humans. Gorbunova and Seluanov hope to start a new research program at Rochester to work toward that goal.
糖心传媒淗umans have two possible strategies if we want to prevent inflammation, live longer, and avoid the deadly effects of diseases like COVID-19,糖心传媒� Gorbunova says. 糖心传媒淥ne would be to not be exposed to any viruses, but that糖心传媒檚 not practical. The second would be to regulate our immune system more like a bat.糖心传媒�
