Occludin Regulates HIV-1 Infection by Modulation of the Interferon Stimulated OAS Gene Family

Characterization and expression profiling of buffalo IFN-lambda family

Interferon lambda (IFN-λ) is an important type III interferon triggered mainly by viral infection. IFN-λ binds to their heterodimeric receptors and signals through JAK-STAT pathways similar to type I IFN. In this study, we deduced the buffalo IFN-λ sequences through the polymerase chain reaction, and then studied IFN-λ's expression patterns in different tissues, and post induction with poly I:C and live MRSA using RT-qPCR. The full-length sequences of buffalo IFN-λ3, IFN-λ receptors, and a transcript variant of IFN-λ4 were determined. IFN-λ1 is identified as a pseudogene. Virus response elements and a recombination hotspot factor was observed in the regulatory region of IFN-λ. The IFN-λ3 expressed highest in lungs and monocytes but IFN-λ4 did not. The expression of Interferon Lambda Receptor 1 was tissue specific, while Interleukin 10 Receptor subunit beta was ubiquitous. Following poly I:C induction, IFN-λ3 expression was primarily observed in epithelial cells as opposed to fibroblasts, displaying cell type-dependent expression. The cytosolic RNA sensors were expressed highest in endometrial epithelial cells, whereas the endosomal receptor was higher in fibroblasts. 2',5'-oligoadenylate synthetase expressed higher in fibroblasts, myxoma resistance protein 1 and IFN-stimulated gene 56 in epithelial cells, displaying cell-specific antiviral response of the interferon stimulated genes (ISGs). The endometrial epithelial cells expressed IFN-λ3 after live S. aureus infection indicating its importance in bacterial infection. The induction of IFN-λ3 was S. aureus isolate specific at the same multiplicity of infection (MOI). This study elucidates the IFN-λ sequences, diverse expression patterns revealing tissue specificity, and specificity in response to poly I:C and bacterial stimuli, emphasising its crucial role in innate immune response modulation.

Targeting HIV persistence in the tissue

PURPOSE OF REVIEW

The complex nature and distribution of the HIV reservoir in tissue of people with HIV remains one of the major obstacles to achieve the elimination of HIV persistence. Challenges include the tissue-specific states of latency and viral persistence, which translates into high levels of reservoir heterogeneity. Moreover, the best strategies to reach and eliminate these reservoirs may differ based on the intrinsic characteristics of the cellular and anatomical reservoir to reach.

RECENT FINDINGS

While major focus has been undertaken for lymphoid tissues and follicular T helper cells, evidence of viral persistence in HIV and non-HIV antigen-specific CD4 + T cells and macrophages resident in multiple tissues providing long-term protection presents new challenges in the quest for an HIV cure. Considering the microenvironments where these cellular reservoirs persist opens new venues for the delivery of drugs and immunotherapies to target these niches. New tools, such as single-cell RNA sequencing, CRISPR screenings, mRNA technology or tissue organoids are quickly developing and providing detailed information about the complex nature of the tissue reservoirs.

SUMMARY

Targeting persistence in tissue reservoirs represents a complex but essential step towards achieving HIV cure. Combinatorial strategies, particularly during the early phases of infection to impact initial reservoirs, capable of reaching and reactivating multiple long-lived reservoirs in the body may lead the path.