London: Scientists have analysed the presence throughout the human body of a protein which the novel coronavirus uses to enter host cells, and have found that it is produced only at "very low levels, if at all," in the respiratory system, an advance which highlights the need for further studies to reassess the biological mechanisms responsible for COVID-19.

The study, published in the journal Molecular Systems Biology, presented a systematic evaluation of the production of ACE2 -- the 'coronavirus entry gate' protein -- in more than 150 cell types in the human body.

It noted that the protein expression was consistently high in the intestines, kidney, gallbladder, heart, male reproductive organs, placenta, eye and vascular tissues, while it was limited in the respiratory system.

"Previous studies have indicated that ACE2 protein is highly expressed in the human lung. But these expression profiles have not been reliably presented along with tissues and organs from the entire human body, or based on several different datasets," said study senior author Cecilia Lindskog from Uppsala University in Sweden.

"Here, in contrast to previous studies, we were able to confidently show that no ACE2 protein is present, or that it occurs at only very low levels, in the normal respiratory system," Lindskog said.Earlier studies had suggested that the novel coronavirus SARS-CoV-2 employs ACE2 for host cell entry, and that penetration of the virus via this receptor would explain the severe clinical manifestations observed in various tissues and organs, including the respiratory system.

"Considering the clinical manifestations of COVID-19, with acute respiratory distress syndrome and extensive damage to the lung parenchyma, the results highlight the need for further study of the biological mechanisms responsible for COVID-19 infection and disease progression," Lindskog said.

"Further studies addressing the dynamic regulation of ACE2, and to confirm whether the low ACE2 expression in the human respiratory system is sufficient for SARS-CoV-2 infection, or whether other factors are needed for host cell entry, are urgently needed," she added.



 

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Gurugram (PTI): A petrol pump worker died after an SUV rammed into his motorcycle in the Sushant Lok area here, police said on Thursday.

The accused driver fled the scene, leaving the vehicle after the accident. An FIR has been registered at the Sushant Lok police station, they said.

According to police, the accident occurred on Wednesday afternoon when Mukesh was travelling from Sector 44 to Sushant Lok on Vyapar Kendra Road for some work.

Near Vyapar Kendra, a white Thar coming from the wrong side at high speed hit his motorcycle head-on, leaving him critically injured, they said.

The driver fled the scene, leaving the vehicle behind, police added.

Eyewitnesses claimed the vehicle had no number plates either at the front or rear.

Locals took Mukesh to a private hospital, where he died during treatment, police said. He was a resident of Rohta Patti in Palwal and worked at a petrol pump in Sector 44.

An FIR was registered against the unidentified driver, based on a complaint lodged by his brother Ashok. The body was handed over to the family after a post-mortem on Thursday, police said.

“The Thar vehicle has been seized from the spot. CCTV footage from the area is being examined, and the driver will be arrested soon,” a Gurugram police spokesperson said.