Analisis Bioinformatika dan Ekspresi Protein Rekombinan Hemagglutinin Domain Globular dari Virus H5N1 Indonesia pada Eschericia coli BL21 (DE3) sebagai Komponen Vaksin Subunit Influenza

Flu burung merupakan salah satu penyakit zoonosis yang patut diwaspadai di Indonesia, khususnya galur High Pathogenic Avian Influenza (HPAI) karena dapat mematikan jika menular kepada manusia. Penggunaan vaksin influenza pada unggas, merupakan langkah preventif terhadap evolusi virus yang berbahaya dan juga penyebarannya. Selama ini, Indonesia masih menggunakan seed vaksin impor yang berasal dari luar Indonesia. Namun, karena Indonesia merupakan negara yang berada di garis khatulistiwa, karakteristik virus bisa berbeda dengan virus dari nothern-hemispere maupun southern-hemispere. Mengingat hal tersebut, Indonesia harus mengembangkan vaksin influenza menggunakan galur virus lokal. Berbeda dengan vaksin whole virus, vaksin rekombinan memiliki keunggulan dari sisi kemurnian, kecepatan produksi, dan kesesuaian galur terhadap virus yang beredar saat diperlukan. Penelitian ini bertujuan untuk menganalisis sekuen hemagglutinin (HA) Indonesia dengan strain lainnya serta mengekspresikkan protein HA1 rekombinan pada Escherichia coli BL21 (DE3). Galur yang digunakan pada studi ini berasal dari virus H5N1 (A/Indonesia/05/05), khususnya bagian domain globular dari HA1. Sekuen HA1 bervariasi antara strain Indonesia dengan nothern-hemispere maupun southern-hemispere dan merupakan protein yang terpapar ke luar virus. Gen HA1 disisipkan pada vektor pET-28a, kemudian plasmid diisolasi menggunakan meoe manniatis, setelah itu diekspresikan dengan induksi 1 mM IPTG selama 4 jam. Protein HA1 telah berhasil diekspresikan secara intraseluler dan telah dikonfirmasi pada berat molekul 40 kDa menggunakan SDS-PAGE. Penelitian ini dapat digunakan untuk mengembangkan vaksin subunit yang lebih spesifik terhadap virus yang beredar di lapangan.

MARCH8 Inhibits Ebola Virus Glycoprotein, Human Immunodeficiency Virus Type 1 Envelope Glycoprotein, and Avian Influenza Virus H5N1 Hemagglutinin Maturation

ABSTRACT Membrane-associated RING-CH-type 8 (MARCH8) strongly blocks human immunodeficiency virus type 1 (HIV-1) envelope glycoprotein (Env) incorporation into virions by downregulating its cell surface expression, but the mechanism is still unclear. We now report that MARCH8 also blocks the Ebola virus (EBOV) glycoprotein (GP) incorporation via surface downregulation. To understand how these viral fusion proteins are downregulated, we investigated the effects of MARCH8 on EBOV GP maturation and externalization via the conventional secretion pathway. MARCH8 interacted with EBOV GP and furin when detected by immunoprecipitation and retained the GP/furin complex in the Golgi when their location was tracked by a bimolecular fluorescence complementation (BiFC) assay. MARCH8 did not reduce the GP expression or affect the GP modification by high-mannose N-glycans in the endoplasmic reticulum (ER), but it inhibited the formation of complex N-glycans on the GP in the Golgi. Additionally, the GP O-glycosylation and furin-mediated proteolytic cleavage were also inhibited. Moreover, we identified a novel furin cleavage site on EBOV GP and found that only those fully glycosylated GPs were processed by furin and incorporated into virions. Furthermore, the GP shedding and secretion were all blocked by MARCH8. MARCH8 also blocked the furin-mediated cleavage of HIV-1 Env (gp160) and the highly pathogenic avian influenza virus H5N1 hemagglutinin (HA). We conclude that MARCH8 has a very broad antiviral activity by prohibiting different viral fusion proteins from glycosylation and proteolytic cleavage in the Golgi, which inhibits their transport from the Golgi to the plasma membrane and incorporation into virions. IMPORTANCE Enveloped viruses express three classes of fusion proteins that are required for their entry into host cells via mediating virus and cell membrane fusion. Class I fusion proteins are produced from influenza viruses, retroviruses, Ebola viruses, and coronaviruses. They are first synthesized as a type I transmembrane polypeptide precursor that is subsequently glycosylated and oligomerized. Most of these precursors are cleaved en route to the plasma membrane by a cellular protease furin in the late secretory pathway, generating the trimeric N-terminal receptor-binding and C-terminal fusion subunits. Here, we show that a cellular protein, MARCH8, specifically inhibits the furin-mediated cleavage of EBOV GP, HIV-1 Env, and H5N1 HA. Further analyses uncovered that MARCH8 blocked the EBOV GP glycosylation in the Golgi and inhibited its transport from the Golgi to the plasma membrane. Thus, MARCH8 has a very broad antiviral activity by specifically inactivating different viral fusion proteins.

Bird flu in Nepal

Avian flu also known as bird flu is caused by deadly virus H5N1 which initially was found in birds and wild animals, however, later it was found in human beings causing severe respiratory related problems. This review article was performed to understand the epidemiology of outbreaks of H5N1 in different districts of Nepal. First outbreak of strain H5N1 was reported in 2009. Consequently, highest number of outbreaks i.e. 201 was noted in the year 2013. Till date only one human case was identified by NPHL which was later confirmed by genetic laboratory in Japan in collaborating with WHO.

The Novel coronavirus outbreak: A challenge beyond borders

Coronaviruses infect mammals and birds worldwide, and some of these viruses infect humans to cause mild to moderate lower-respiratory tract illnesses and rarely a severe illness. Like other viruses, coronaviruses evolved (change their genetic material and protein structure) and spread from animals to humans. The world has witnessed coronavirus evolving into severe acute respiratory syndrome coronavirus (SARS-CoV) in 2003 and the Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012. Other recent examples include Dengue, Ebola, Chikungunya, Influenza and Zika virus outbreaks. It may or may not be relevant to note that first cases of both SARS-CoV in 2003 avian influenza virus (H5N1) in 1997 were isolated and identified at the same hospital in Hong Kong where the first case of the current outbreak of the Wuhan coronavirus has been identified. The new virus has been named as the Novel coronavirus (2019 nCoV).

QSAR study of N-substituted oseltamivir derivatives as potent avian influenza virus H5N1 inhibitors using quantum chemical descriptors and statistical methods

In silico modelling studies were executed on thirty two N-substituted oseltamivir derivatives as inhibitors of influenza virus H5N1.