Author Correction: Atg9 is a lipid scramblase that mediates autophagosomal membrane expansion

Human WIPI β-propeller function in autophagy and neurodegeneration

The four human WIPI β-propellers, WIPI1 through WIPI4, belong to the ancient PROPPIN family and fulfill scaffold functions in the control of autophagy. In this context, WIPI β-propellers function as PI3P effectors during autophagosome formation and loss of WIPI function negatively impacts autophagy and contributes to neurodegeneration. Of particular interest are mutations in WDR45, the human gene that encodes WIPI4. Sporadic WDR45 mutations are the cause of a rare human neurodegenerative disease called BPAN, hallmarked by high brain iron accumulation. Here, we discuss the current understanding of the functions of human WIPI β-propellers and address unanswered questions with a particular focus on the role of WIPI4 in autophagy and BPAN.

H1Innovative approaches to combat anti-cancer drug resistance: Targeting lncRNA and autophagy

BACKGROUND

To date, standardizing clinical predictive biomarkers for assessing the response to immunotherapy remains challenging due to variations in personal genetic signatures, tumour microenvironment complexities and epigenetic onco-mechanisms.

MAIN BODY

Early monitoring of key non-coding RNA (ncRNA) biomarkers may help in predicting the clinical efficacy of cancer immunotherapy and come up with standard predictive ncRNA biomarkers. For instance, reduced miR-125b-5p level in the plasma of non-small cell lung cancer patients treated with anti-PD-1 predicts a positive outcome. The level of miR-153 in the plasma of colorectal cancer patients treated with chimeric antigen receptor T lymphocyte (CAR-T) cell therapy may indicate the activation of T-cell killing activity. miR-148a-3p and miR-375 levels may forecast favourable responses to CAR-T-cell therapy in B-cell acute lymphoblastic leukaemia. In cancer patients treated with the GPC3 peptide vaccine, serum levels of miR-1228-5p, miR-193a-5p and miR-375-3p were reported as predictive biomarkers of good response and improved overall survival. Therefore, there is a critical need for further studies to elaborate on the key ncRNA biomarkers that have the potential to predict early clinical responses to immunotherapy.

CONCLUSIONS

This review summarises important predictive ncRNA biomarkers that were reported in cancer patients treated with different immunotherapeutic modalities including monoclonal antibodies, small molecule inhibitors, cancer vaccines and CAR-T cells. In addition, a concise discussion on forthcoming perspectives is provided, outlining technical approaches for the optimal utilisation of immune-modulatory ncRNA biomarkers as predictive tools and therapeutic targets.

ATG9A supports Chlamydia trachomatis infection via autophagy-independent mechanisms

Chlamydia trachomatis infection can be regulated by autophagy-related (ATG) genes. Here, we found that the depletion of ATG9A, one of the core ATG genes, in HeLa cells suppressed C. trachomatis growth in the inclusion. The growth was restored by re-expressing ATG9A or an ATG9A mutant impairing lipid scramblase activity in ATG9A-knockout (KO) cells. Moreover, the depletion of lipid transfer proteins ATG2A/B, responsible for isolation membrane expansion together with ATG9A, did not significantly alter the growth, suggesting that the non-autophagic function of ATG9A supports C. trachomatis infection. ATG9A-KO cells showed no infection-induced redistribution of the Golgi from the perinuclear region to inclusion, which was restored by re-expressing the mutant but not the ATG9A mutant lacking an N-terminal adapter protein-binding domain. Re-expression of the N-terminal deletion mutant in ATG9A-KO cells did not rescue C. trachomatis growth, suggesting the importance of this domain for its growth. Although ATG9A-KO cells showed enhanced TBK1 activation, interferon (IFN)-β was not significantly increased, excluding the possibility that upregulation of stimulator of IFN genes (STING) signaling suppressed bacterial growth. Taken together, these findings suggest that the proper trafficking, rather than the isolation membrane expansion function, of ATG9A assists C. trachomatis growth in the inclusion. IMPORTANCE ATG9A is an autophagy-related gene that functions during the isolation membrane expansion process to form autophagosomes, but it also has other functions independent of autophagy. In this study, we employed ATG9A-deficient HeLa cells and found that the absence of ATG9A negatively impacted proliferation of Chlamydia trachomatis in inclusions. Furthermore, rescue experiments using ATG9A mutants revealed that this action was mediated not by its autophagic function but by its binding ability to clathrin adapter proteins. These findings suggest that the proper trafficking of ATG9A assists C. trachomatis growth in the inclusion.

The Macroautophagy Machinery in MHC Restricted Antigen Presentation

Autophagy-related (ATG) gene products regulate macroautophagy, LC3-associated phagocytosis (LAP) and LC3-dependent extracellular vesicle loading and secretion (LDELS). These processes also influence antigen processing for presentation on major histocompatibility complex (MHC) molecules to T cells. Here, I summarize how these different pathways use the macroautophagy machinery, contribute to MHC class I and II restricted antigen presentation and influence autoimmunity, tumor immunology and immune control of infectious diseases. Targeting these different pathways should allow the regulation of intracellular and extracellular antigen presentation to T cells to modulate protective and pathological immune responses.

"VTT"-domain proteins VMP1 and TMEM41B function in lipid homeostasis globally and locally as ER scramblases

Recent studies have identified the metazoan ER-resident proteins, TMEM41B and VMP1, and so structurally related VTT-domain proteins, as glycerolipid scramblases.